Yin Chiao Chieh Tu Pien [Discontinued] by Plum Flower

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there is interest in using topical burdock for acne, there is insufficient reliable information about the clinical effects of burdock for this purpose.
• Aging skin. It is unclear if topical burdock is beneficial for reducing wrinkles. Details: A very small study in females aged 39-65 years shows that applying an emulsion containing burdock fruit extract 1.2% to the face twice daily for 4 weeks slightly reduces skin wrinkles around the eyes when compared with placebo (37420).
• Atopic dermatitis (eczema). Although there is interest in using topical burdock for eczema, there is insufficient reliable information about the clinical effects of burdock for this condition.
• Breast cancer. Oral burdock root has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Population research in breast cancer patients has found that using a specific product containing burdock root, sheep sorrel, slippery elm bark, and Indian rhubarb (Essiac, Resperin Canada Limited) is not associated with improved quality of life when compared with no intervention (37419).
• Common cold. Although there is interest in using oral burdock for symptoms of the common cold, there is insufficient reliable information about the clinical effects of burdock for this condition.
• Diabetes. Although there is interest in using oral burdock for diabetes, there is insufficient reliable information about the clinical effects of burdock for this condition.
• Diverticulitis. It is unclear if oral burdock is beneficial in patients with diverticulitis. Details: A small open-label clinical study in patients with colonic diverticulitis shows that taking burdock tea (Ajikan, Co., Ltd.) providing 1.5 grams three times daily for a median of 26 months is associated with an acute diverticulitis recurrence rate of 11%, compared with 32% of those not taking burdock tea. Furthermore, the recurrence-free duration was increased by about 14 months. However, taking burdock tea for a median of 16 months does not prevent colonic diverticular bleeding recurrence (102696).
• Dry skin. Although there is interest in using topical burdock for dry skin, there is insufficient reliable information about the clinical effects of burdock for this purpose.
• Gout. Although there is interest in using oral burdock for gout, there is insufficient reliable information about the clinical effects of burdock for this condition.
• Hepatitis. Although there is interest in using oral burdock for hepatitis, there is insufficient reliable information about the clinical effects of burdock for this condition.
• Metabolic syndrome. It is unclear if oral burdock is beneficial in patients with metabolic syndrome. Details: A very small clinical study in patients with metabolic syndrome shows that drinking burdock extract 100 mL three times daily after meals for 16 weeks does not reduce body weight, abdominal fat, blood pressure, lipid levels, or glucose when compared with baseline or control (105667).
• Obesity. Although there is interest in using oral burdock for obesity, there is insufficient reliable information about the clinical effects of burdock for this condition.
• Urinary tract infections (UTIs). Although there is interest in using oral burdock for UTI, there is insufficient reliable information about the clinical effects of burdock for this condition.
• Vaginitis. Topical burdock has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Observational research in adults and children with vaginitis has found that applying a specific solution containing burdock, chamomile, and aloe (Zelesse, ITF Research Pharma S.L.U., Alcobendas) to the vaginal area once or twice daily for 5-20 days is associated with moderate improvements in symptoms such as pruritus, erythema, and discharge when compared with baseline (102695,102697). The validity of this finding is limited by its observational nature and the lack of a control group. More evidence is needed to rate burdock for these uses.

(Read more about BURDOCK)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Bronchiolitis. Preliminary clinical research suggests a combination of forsythia, honeysuckle, and Baikal skullcap given intravenously might decrease the duration of symptoms of bronchiolitis in children with respiratory syncytial virus infection (12613). More evidence is needed to rate forsythia for this use.

(Read more about FORSYTHIA)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related cognitive decline. It is unclear if oral honeysuckle extract is beneficial in patients with age-related cognitive decline. Details: A small clinical study in elderly adults shows that taking honeysuckle (Lonicera caerulea) berry extract 200-400 mg, 90 minutes prior to a cognitive test, improves episodic memory, but not working memory or executive function tasks, when compared with placebo (103876). The long-term effects of honeysuckle on cognitive decline are unclear.
• Atopic dermatitis (eczema). Although there has been interest in using topical honeysuckle for atopic dermatitis, there is insufficient reliable information about the clinical effects of honeysuckle for this purpose.
• Bronchiolitis. Intravenous honeysuckle has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in children with respiratory syncytial virus (RSV) infection shows that intravenous administration of a combination of honeysuckle, Baikal skullcap, and forsythia might decrease the duration of symptoms of bronchiolitis when compared with a control group (12613). It is unclear if these findings are due to honeysuckle, other ingredients, or the combination.
• Diabetes. Although there has been interest in using oral honeysuckle for diabetes, there is insufficient reliable information about the clinical effects of honeysuckle for this purpose.
• Dyspepsia. It is unclear if oral honeysuckle flower bud extract is beneficial in patients with dyspepsia. Details: A small clinical study in patients with functional dyspepsia shows that taking honeysuckle (Lonicera japonica) flower bud extract 125 mg twice daily for 8 weeks improves gastrointestinal symptom scores when compared with placebo (103877).
• Postoperative infection. Topical honeysuckle has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large open-label trial in adults with obstructive sleep apnea recovering from uvulopalatopharyngoplasty shows that gargling with honeysuckle in combination with numerous other herbs 25 mL for 5 minutes 4 times daily for 2 weeks does not reduce post-operative wound infection when compared with saline placebo (112867). The interpretation of this study is limited by the unclear dose of honeysuckle.
• Postoperative pain. Topical honeysuckle has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large open-label trial in adults with obstructive sleep apnea recovering from uvulopalatopharyngoplasty shows that gargling with honeysuckle in combination with numerous other herbs 25 mL for 5 minutes 4 times daily for 2 weeks improves post-operative resting, swallowing throat pain, and patient comfort when compared with saline placebo (112867). It is unclear if this effect is due to honeysuckle, other ingredients, or the combination. The interpretation of this study is also limited by the unclear dose of honeysuckle.
• Pruritus. Although there has been interest in using topical honeysuckle for pruritus, there is insufficient reliable information about the clinical effects of honeysuckle for this purpose.
• Respiratory tract infections. Although there has been interest in using oral honeysuckle for various respiratory tract infections, including bronchitis, the common cold, influenza, and pneumonia, there is insufficient reliable information about the clinical effects of honeysuckle for these conditions.
• Rheumatoid arthritis (RA). Although there has been interest in using oral honeysuckle for RA, there is insufficient reliable information about the clinical effects of honeysuckle for this purpose.
• Urinary tract infections (UTIs). Although there has been interest in using oral honeysuckle for UTIs, there is insufficient reliable information about the clinical effects of honeysuckle for this purpose.
• Wound healing. Although there has been interest in using topical honeysuckle for wound healing, there is insufficient reliable information about the clinical effects of honeysuckle for this purpose. More evidence is needed to rate honeysuckle for these uses.

(Read more about HONEYSUCKLE)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Bronchitis. Although there has been interest in using inhaled Japanese mint for bronchitis, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Cancer. Although there has been interest in using oral Japanese mint for cancer, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Common cold. Although there has been interest in using oral Japanese mint for common cold, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Cough. Although there has been interest in using oral Japanese mint for cough, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Diarrhea. Although there has been interest in using oral Japanese mint for diarrhea, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Dyspepsia. Although there has been interest in using oral Japanese mint for dyspepsia, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Flatulence. Although there has been interest in using oral Japanese mint for flatulence, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Headache. Although there has been interest in using oral Japanese mint for headache, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Irritable bowel syndrome (IBS). Although there has been interest in using oral Japanese mint for IBS, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Joint pain. Although there has been interest in using topical Japanese mint for joint pain, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Myalgia. Although there has been interest in using topical Japanese mint for myalgia, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Neuropathic pain. Although there has been interest in using topical Japanese mint for neuropathic pain, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Sore throat. Although there has been interest in using oral Japanese mint for sore throat, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Toothache. Although there has been interest in using oral Japanese mint for toothache, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose.
• Urticaria. Although there has been interest in using topical Japanese mint for urticaria, there is insufficient reliable information about the clinical effects of Japanese mint for this purpose. More evidence is needed to rate Japanese mint for these uses.

(Read more about JAPANESE MINT)

POSSIBLY EFFECTIVE

• Atopic dermatitis (eczema). Some clinical research suggests that topical licorice seems to improve symptoms of atopic dermatitis. Details: Applying gel formulations containing 1% or 2% licorice root extract three times daily for 2 weeks seems to reduce erythema by 35% to 61%, edema by 57% to 84%, and itching by 44% to 73%. The 2% gel seems to be more effective than the 1% gel (59732).
• Canker sores. Some clinical research suggests that topical licorice patches and mouth rinses seems to reduce ulcer size and pain in patients with recurrent aphthous stomatitis. Details: Clinical research shows that applying an oral patch containing licorice 0.015-0.229 mg/kg for 16 hours each day for 8 days does not affect ulcer healing time, but reduces ulcer size and post-stimulus pain, when compared with placebo (59769). A small clinical study also shows that applying bioadhesive hydrogel patches containing 1% licorice extract reduces the pain, as well as the diameter of necrosis and inflammatory halo of recurrent canker sores, when compared to baseline (59781). Mouth rinses containing licorice have also been used. One clinical study shows that swishing a diphenhydramine and 5% licorice extract solution around the mouth for about 3 minutes four times daily until the sores have healed reduces the average time to healing by 1.5 days when compared to a solution containing diphenhydramine alone. Pain was reduced by up to 69% more in those using licorice extract (104564). Another small clinical study shows that gargling with licorice extract four times daily for 2 days has a large beneficial effect on pain and ulcer size when compared with using a placebo gargle. The licorice extract was made by boiling licorice root 40 grams in one liter of water for 30 minutes and cooled (110319). In addition, preliminary clinical research shows that gargling with warm water containing deglycyrrhizinated licorice powder 200 mg four times daily for 7 days improves pain in 75% of patients by day one and results in complete healing in 75% of patients by day three (59857).
• Endotracheal intubation-related adverse effects. Some clinical research suggests that using licorice as a gargle or lozenge prior to endotracheal intubation can reduce adverse effects like sore throat and cough. Details: A meta-analysis of 5 clinical trials in patients undergoing elective surgical procedures shows that topical use of licorice, either as a gargle or lozenge, prior to endotracheal intubation reduces the risk for sore throat by 56% and reduces the risk for cough by 39% when compared with a control group at 24 hours post-extubation (100985). One clinical study included in this analysis shows that sucking on a single lozenge (Sualin, Hamdard Pharma) containing licorice extract 97 mg beginning 30 minutes prior to intubation reduces the risk for cough immediately after extubation by 56% when compared with a sugar candy lozenge. However, it doesn't seem to reduce cough at 30 minutes, 12 hours, or 24 hours post-extubation. This lozenge also appears to reduce the risk for sore throat by about 32% at 12 and 24 hours post-extubation, but not immediately or 30 minutes after extubation (25670). Additional clinical studies included in the meta-analysis show that gargling with fluid prepared with licorice 0.5 grams for at least one minute beginning 5 minutes prior to endotracheal intubation reduces the incidence and severity of post-extubation sore throat and coughing when compared with a water control (26464,59793).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Topical licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in patients with mild to moderate acne associated with mask wearing shows that topical application of a combination of licorice root extract 0.3%, calendula 4%, and snail secretion filtrate 40% (AI complex) to the face twice daily for 12 weeks modestly reduces inflammatory, but not non-inflammatory or total, acne lesions when compared with placebo. There was no difference in overall treatment success, defined as at least almost clear skin or a large improvement (110322). It is unclear if any benefits are due to licorice, other ingredients, or the combination.
• Addison disease. Although there has been interest in using oral licorice for Addison disease, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Adrenal insufficiency. Although there has been interest in using oral licorice for adrenal insufficiency, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Allergic rhinitis (hay fever). It is unclear if using a licorice-containing nasal irrigation suspension improves symptoms in patients with allergic rhinitis. Details: A clinical study in patients with allergic rhinitis shows that using a nasal irrigation suspension containing licorice extract 900 mg daily for 1 month improves symptoms such as nasal blockage, rhinorrhea, sneezing, postnasal discharge, and olfactory disturbance when compared with baseline (108569). Although the study also utilized mometasone 2 mg nasal spray and isotonic saline nasal irrigation as comparators, symptom improvement was observed in all three groups, and there was no statistical comparison of outcomes between groups.
• Antipsychotic-induced hyperprolactinemia. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in females with risperidone-induced hyperprolactinemia shows that taking a combination of licorice and peony (Peony-Glycyrrhiza Decoction; PGD) 45 grams daily for 4 weeks reduces prolactin levels to a similar extent as bromocriptine (59775). However, another study shows that taking the same product at the same dose for 16 weeks has no effect on prolactin levels in females with antipsychotic-induced hyperprolactinemia when compared with placebo. Although the prolactin-related adverse event questionnaire total score was moderately improved, there was no effect on clinically meaningful symptoms or menstrual resumption (97219). Both studies show no effect on psychotic symptoms (59775,97219). Preliminary clinical research in male patients with antipsychotic-induced hyperprolactinemia shows that taking an herbal extract containing licorice and peony (shakuyaku-kanzo-to) 2.5 grams three times daily reduces prolactin levels after 4 weeks, but does not have a significant effect on prolactin levels 4 weeks after treatment cessation (59907).
• Asthma. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study conducted in Iran in children and adolescents aged 6-18 years old with mild-to-moderate asthma shows that taking a combination of licorice, sweet violet, and jalap (Anti-Asthma, Sinafaravar) twice daily for a month in addition to standard therapy reduces cough severity but does not change shortness of breath frequency or severity, rescue inhaler use, respiratory indices, or perceptions of asthma severity when compared with placebo (113569). It is unclear whether this effect is due to licorice, other ingredients, or the combination.
• Bleeding. Topical licorice might reduce bleeding when used in combination with other ingredients; its effect when used alone is unclear. Details: Some preliminary clinical research shows that topically applying 4 mL of a specific product (Ankaferd Blood Stopper, Mefar Ilaç Sanayi A.S.) containing licorice, Alpinia, thyme, stinging nettle, and common grape vine reduces bleeding, but does not improve the surgical time for episiotomy repair, when compared with saline (31010). Other preliminary clinical research shows that ampules of this same product placed in empty alveolus for up to 20 minutes reduces bleeding in postsurgical dental patients with increased bleeding tendency (31002).
• Cancer-related pain. It is unclear if oral licorice is beneficial for pain in patients with cancer. Details: Preliminary clinical research shows that taking a 1:1 combination of licorice root and peony root, along with a Taiwanese tonic vegetable soup comprised of lily bulb, lotus seed, and jujube fruit, reduces pain levels in terminal cancer patients when compared with patients consuming only the soup or the regular hospital diet (59770).
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral licorice for CFS, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Colic. Although there has been interest in using oral licorice for colic, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Coronavirus disease 2019 (COVID-19). It is unclear whether oral licorice is beneficial for COVID-19. Details: A small open-label study in adults in Iran with moderate COVID-19 shows that taking licorice (D-Reglis, Irandarouk Pharmaceutical Company) 760 mg three times daily for 7 days in addition to standard treatment with hydroxychloroquine 200 mg twice daily for 7 days does not improve oxygen saturation, temperature, respiratory rate, clinical symptoms, length of hospital stay, or mortality, when compared with standard treatment alone (113633). As part of a combination treatment, a small clinical study in patients hospitalized in Egypt with moderate COVID-19 shows that administering oral licorice extract 300 mg (standardized to contain glycyrrhizin 60 mg) once daily and Boswellia serrata extract 300 mg twice daily for 14 days, along with following an institution-based COVID-19 treatment protocol, may modestly improve mortality and time to recovery when compared with patients receiving the standard protocol alone. The standard treatment protocol included acetaminophen, azithromycin, vitamin C, zinc, and enoxaparin (108579). It is unclear if any effect is due to licorice, Boswellia serrata, or the combination.
• Dental caries. It is unclear if oral licorice is beneficial for the prevention of dental caries. Details: One clinical study in adults shows that swishing 15 mL of a solution containing licorice extract 1% once nightly before bed for 5 days may reduce the acid production of cavity-causing bacteria, which may modestly reduce cavity risk, when compared with using a saline solution (108567). The validity of this study is limited by the short duration of treatment and follow-up.
• Dental plaque. It is unclear if licorice toothpaste or mouthwash is beneficial for reducing plaque. Details: Preliminary clinical research shows that using 0.25% or 0.50% glycyrrhizin-containing toothpaste twice daily does not reduce the amount of plaque, gingivitis, or bleeding in patients with proper dental hygienic measures when compared with the same toothpaste without glycyrrhizin (59812). Also, other preliminary clinical research shows that using glycyrrhizin-containing mouthwash for 3 days does not significantly reduce plaque levels (59855).
• Depression. It is unclear if adding oral licorice to standard treatment is beneficial for improving depression. Details: A very small, nonblinded clinical study in hospitalized adults with major depressive disorder shows that adding licorice extract 1400 mg daily, standardized to glycyrrhizin 7% to 8%, to standard treatment for 2 weeks improves depression rating scores when compared with baseline, although these improvements were numerically similar to those seen with standard treatment alone. Patients in the treatment group also took oral magnesium citrate 300 mg daily to prevent magnesium depletion. The validity of this finding is limited due to the small size of the study, short duration of treatment, and unclear reporting (108575).
• Diabetes. Although there has been interest in using oral licorice for diabetes, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Dry mouth. It is unclear if rinsing the mouth with licorice is beneficial for dry mouth in people on hemodialysis. Details: Preliminary clinical research in hemodialysis patients with dry mouth shows that rinsing with a licorice mouthwash containing 8.34 grams of licorice concentrate per 500 mL of water with every meal for 10 days does not affect salivary flow rate, but reduces subjective feelings of dry mouth by about 28%, when compared with a water-based mouthwash and control group (97220).
• Dysmenorrhea. It is unclear if oral licorice is beneficial for reducing pain. Details: Preliminary clinical research shows that taking a syrup providing licorice extract 750 mg twice daily for the first 5 days of the menstrual cycle reduces pain as effectively as ibuprofen 400 mg every 8 hours in patients with moderate or severe dysmenorrhea (104558).
• Dyspepsia. Oral licorice might improve symptoms of dyspepsia when used in combination with other ingredients; its effect when used alone is unclear. Details: Various combination products manufactured by Steigerwald Arzneimittelwerk GmbH have been evaluated for dyspepsia. Two specific combination products containing licorice root (Iberogast; STW-5-S) seem to improve symptoms of dyspepsia. The combinations include licorice plus milk thistle, peppermint leaf, German chamomile, caraway, celandine, angelica, and lemon balm either with (Iberogast) or without clown's mustard plant (STW-5-S) 1 mL three times daily for 4 weeks (19532). A meta-analysis of studies using the Iberogast product shows that taking 1 mL orally three times daily over a period of 4 weeks reduces severity of acid reflux, epigastric pain, cramping, nausea, and vomiting when compared with placebo (13089). Also, using a preparation containing clown's mustard plant, German chamomile, peppermint, caraway, licorice, and lemon balm (STW 5-II) 1 mL three times daily for up to 12 weeks improves dyspepsia symptoms in 40% more patients when compared with placebo (12724).
• Familial Mediterranean fever. It is unclear if oral licorice is beneficial for familial Mediterranean fever. Details: Preliminary clinical research shows that taking a combination of licorice, andrographis, Siberian ginseng, and schisandra (ImmunoGuard, Inspired Nutritionals) four tablets three times daily for one month reduces the duration, frequency, and severity of attacks of familial Mediterranean fever in children when compared with placebo (12382). It is unclear if these effects are due to licorice, other ingredients, or the combination.
• Helicobacter pylori. It is unclear if oral licorice is beneficial for Helicobacter pylori eradication. Details: Some preliminary clinical research shows that adding licorice (D-Reglis, Iran Darouk Pharmaceutical Co.) 380 mg twice daily to conventional clarithromycin-based triple therapy for 14 days improves eradication rate by an additional 21% when compared with conventional treatment alone. However, any additional benefit might be limited to patients with peptic ulcer disease (97221). Other preliminary clinical research shows that taking a combination of licorice extract 100 mg and Lactobacillus paracasei HP7 in 150 mL of fermented milk daily for 8 weeks does not increase eradication rates when compared with fermented milk alone, although it may improve gastrointestinal symptom scores, decrease the gastric load of Helicobacter pylori, and improve some measures of inflammation when compared to baseline (100984).
• Hepatitis. Evidence for the use of intravenous licorice in the management of hepatitis B and C is mixed. Details: In some preliminary clinical research, a specific glycyrrhizin-containing intravenous preparation (Stronger Neominophagen C, Minophagen Pharmaceutical Co. Ltd.) appears to reduce mortality due to viral hepatitis by about 50% (3250). Other clinical research suggests that this same product reduces serum alanine aminotransferase (ALT) in hepatitis C patients but does not improve hepatitis C virus (HCV)-RNA levels (3247,59712,59721,59920). When used long-term, this preparation seems to reduce the risk of hepatocellular carcinoma in hepatitis C patients when compared to long-term use of other supplements, such as vitamin K (59905). This product has been used in various doses: 40 or 100 mL, containing 2 mg glycyrrhizin, 1 mg cysteine, and 20 mg of glycine per mL of solution, administered daily for 4-8 weeks, followed by 40 or 100 mL 2-7 times weekly for 2-16 weeks, has been used (3250,59905,59915); 40-120 mL diluted in 100 mL of 5% glucose solution and administered three times weekly for 4 weeks (59712,59721); 100 mL, which contained 200 mg glycyrrhizin, administered undiluted six times weekly for 4 weeks (59721); or 60 mL administered three times weekly for 16 weeks (59920). Other research shows that this preparation reduces ALT, aspartate aminotransferase (AST), and gamma-glutamyl transpeptidase (GGT) in patients with hepatitis B virus (59915). Oral licorice has not been evaluated for this purpose.
• Hypercholesterolemia. It is unclear if oral licorice is beneficial for improving cholesterol. Details: Preliminary clinical research shows that taking licorice root extract 0.1 grams daily for one month reduces plasma total cholesterol levels by 5%, plasma low-density lipoprotein (LDL) cholesterol levels by 9%, and plasma triglyceride levels by 14% when compared with baseline in patients with moderate hypercholesterolemia (59725). The validity of these findings is limited by the lack of a comparator group.
• Hyperkalemia. It is unclear if oral licorice is beneficial for reducing potassium levels. Details: Some clinical research in adults with diabetes and hypoaldosteronism suggests that taking glycyrrhizin 150 mg daily decreases potassium levels when compared with calcium polystyrene sulfonate (59897). Also, one very small clinical study in patients with anuria shows that taking glycyrrhetinic acid 1 gram daily for 2 weeks seems to decrease plasma potassium, but does not improve blood pressure, when compared with placebo (59723).
• IgA vasculitis. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small retrospective study in patients aged 5-36 years with newly diagnosed IgA vasculitis shows that taking compound glycyrrhizin (Eisai Pharmaceutical Co, Ltd) three times daily along with loratadine, calcium, vitamin C, rutin, and other unspecified conventional treatments is associated with an improvement in cutaneous purpura symptoms and time to symptom regression when compared with placebo. After 1 month, the rate of complete resolution and time to regression in the treatment group was 82% and 5 days, respectively, compared with 65% and 8 days, respectively, in the placebo group. Compound glycyrrhizin contained glycyrrhizin, glycine, and methionine and was dosed by age, with a dose of 25 mg daily in those 12 years or younger and 50 mg daily in those over 12 years (108580).
• Irritable bowel syndrome (IBS). Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that a formulation containing licorice root, slippery elm bark, lactulose, and oat bran daily for 2 weeks improves stool consistency and increases bowel movement frequency by 20% in individuals with constipation-predominant IBS when compared to baseline. Symptoms of abdominal pain, bloating, straining, and global severity might also be reduced (35462). The validity of these findings is limited by the lack of a comparator group. Additionally, it is unclear if any benefits are due to licorice, other ingredients, or the combination.
• Lichen planus. It is unclear if intravenous licorice is beneficial for lichen planus. Details: A very small clinical study shows that intravenous administration of 0.2% glycyrrhizin solution, 40 mL daily for 4 weeks, improves clinical symptoms of oral lichen planus in a greater percentage of patients with chronic hepatitis C when compared with dental cleaning (59903). There is no evidence suggesting that oral licorice is beneficial.
• Liver cancer. Although there has been interest in using oral or intravenous licorice preparations for liver cancer, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Melasma. Topical licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that applying a topical cream (Clariderm Clear, Stiefel Laboratories Inc.) containing 7% licorice, emblica, and belides twice daily for 60 days is as effective as a cream containing 2% hydroquinone for lightening the skin in patients with melasma (59824). It is unclear if this effect is due to licorice, other ingredients, or the combination.
• Menopausal symptoms. It is unclear if oral licorice is beneficial for reducing hot flash frequency or severity. Details: In one preliminary clinical study, taking licorice root extract 330 mg orally three times daily for 8 weeks modestly reduces the frequency of hot flashes by about 1.3 per day and the severity of hot flashes by about 40% when compared with placebo (94659). However, another preliminary clinical study shows that taking a specific licorice root extract (D-Reglis, Iran Darouk Pharmaceutical Co.) 650 mg orally daily for 90 days does not reduce the number or severity of hot flashes when compared to baseline (25694).
• Muscle cramps. It is unclear if oral licorice is beneficial for muscle cramps due to cirrhosis or hemodialysis. Details: Preliminary clinical research shows that taking a specific combination of licorice and peony (shakuyaku-kanzo-to) might reduce muscle cramps in patients with hepatic cirrhosis or in patients undergoing hemodialysis when compared to baseline (13550,13551,13552). This combination was taken as 6-7.5 grams daily in up to three divided doses for 2-4 weeks in two studies (13550,13552). In a third study, the combination was taken as 2.5 grams during hemodialysis with self-administration at the onset of muscle cramping (13551).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral licorice is beneficial for NAFLD. Details: A small clinical trial in females with NAFLD shows that taking licorice extract (Shirin Darou Company, Shiraz, Iran) 500 mg twice daily for 12 weeks improves some measures of liver health and glycemic control when compared with placebo. Modest improvements occurred in levels of alanine aminotransferase, as well as in measures of insulin resistance and severity of liver steatosis based on ultrasonographic evaluation. There were no effects on body mass index (BMI), plasma lipids, fasting blood glucose, or other liver enzymes. All patients were also given weight loss and healthy lifestyle advice (110320). Preliminary clinical research shows that taking licorice root extract 2 grams daily for 2 months reduces liver function enzyme levels in patients with NAFLD when compared to pre-treatment (59841). It is unclear if this reduction is clinically significant.
• Obesity. It is unclear if oral licorice is beneficial for weight loss. Details: Preliminary clinical research shows that taking a specific licorice flavonoid oil (Glavonoid) 300 mg daily for 8 weeks has no effect on weight or body fat when compared with placebo in obese patients (17727).
• Oral mucositis. It is unclear if oral or topical licorice is beneficial for the prevention or treatment of chemotherapy- or radiation-induced oral mucositis. Details: In patients with head and neck cancer undergoing chemoradiation, preliminary clinical research shows that using oral and topical licorice powder twice daily in addition to conventional treatments for 6 weeks reduces the overall incidence of mucositis and also reduces the risk of developing severe oral mucositis to 15.5%, compared with 20% in those using topical honey and 43% in those using conventional treatments alone. Licorice treatment consisted of yastimadhu powder 5 grams mixed in honey for topical application in the mouth, as well as yastimadhu capsule 500 mg twice daily orally (104562). A small clinical trial in patients with head and neck cancer and oral mucositis currently undergoing radiation therapy shows that applying a mucoadhesive film containing licorice to the upper lip mucosal surface four times daily for 4 weeks, in conjunction with standard oral care, improves pain scores, mucositis grading, and ulcer size when compared with placebo film (108572). The validity of this finding is limited due to the short duration of treatment and exclusion of patients with severe mucositis.
• Osteoarthritis. Although there has been interest in using oral licorice for osteoarthritis, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Osteoporosis. Although there has been interest in using oral licorice for osteoporosis, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Parkinson disease. It is unclear if oral licorice is beneficial for improving Parkinson disease symptoms. Details: A small clinical study in patients with Parkinson disease shows that taking licorice extract 136 mg (containing glycyrrhizin 12.14 mg, polyphenols 136 mcg, and flavonoids 2.6 mcg) in a 5 mL syrup twice daily for 6 months improves Parkinson symptoms, tremor, and overall daily activities when compared with placebo (102961).
• Peptic ulcers. Evidence for the use of oral licorice for peptic ulcers is mixed. Details: There is some evidence that taking 6-12 tablets each containing deglycyrrhizinated licorice 380 mg, bismuth subnitrate 100 mg, aluminum hydroxide gel 100 mg, magnesium carbonate 200 mg, sodium bicarbonate 100 mg, and powdered alder buckthorn bark 30 mg (Caved-S, Cedona) in up to three divided doses daily for 4-16 weeks might accelerate the healing of peptic ulcers (11312,11313). Some clinical research also shows that this product is as effective as carbenoxolone sodium (Biogastrone) when taken at doses of two tablets three times daily after meals for 4 weeks (59871). In contrast, taking deglycyrrhizinated licorice (Ulcedal, Cedona, and others) 450-1000 mg three to five times daily for 4-8 weeks or glycyrrhizinic acid-reduced licorice 760 mg three times daily for 6 weeks does not seem to reduce the need for medication, pain, burning, or other discomfort in patients with peptic ulcers when compared with placebo (59864,59865,59873,59874).
• Physical performance. It is unclear if oral licorice is beneficial for improving physical performance in older females. Details: A small clinical trial in healthy females 59 years and older shows that taking licorice flavonoid oil 300 mg orally daily for 16 weeks in addition to strength training does not improve walking speed or other measures of functional mobility when compared with strength training alone (102960).
• Polycystic ovary syndrome (PCOS). Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking licorice root extract 2250 mg daily along with Ceylon cinnamon, levant berry, St. John's Wort, peony, and tribulus for 3 months with lifestyle modification improves symptoms of PCOS, including a reduction in oligomenorrhea/amenorrhea by 33% and the number of days between menstrual cycles by 43 days when compared with lifestyle modification alone. Although conception rate increased 4-fold in the intervention group, live birth rate was similar between groups (97216). The effect of licorice alone for the treatment of PCOS is unknown.
• Prostate cancer. Although there has been interest in using oral licorice for prostate cancer, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Psoriasis. It is unclear if topical licorice is beneficial for improving psoriasis symptoms. Details: Preliminary clinical research shows that using a topical cream containing licorice extract and milk proteins twice daily for 4 weeks does not reduce the duration of corticosteroid cream therapy in patients with palmar and/or plantar psoriasis, but may improve skin peeling, the area of skin affected, and some subjective symptoms, when compared with corticosteroid cream alone (59823).
• Smoking cessation. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in adults in India with a history of smoking 5 or more cigarettes daily for at least 3 years shows that taking a specific combination product containing licorice 200 mg, ashwagandha, cowhage, ginger, turmeric, and other herbal extracts (Smotect, Smotect India) twice daily for 3 months reduces the number of cigarettes smoked daily and levels of alveolar carbon monoxide and carboxyhemoglobin but does not improve lung capacity when compared with placebo (112115). It is unclear if these effects are due to licorice, other ingredients, or the combination.
• Systemic lupus erythematosus (SLE). Although there has been interest in using oral licorice for SLE, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Tuberculosis. Although there has been interest in using oral licorice for tuberculosis, there is insufficient reliable information about the clinical effects of licorice for this condition.
• Urticaria. Oral licorice has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of clinical research in adults with chronic urticaria shows that taking compound glycyrrhizin, containing glycyrrhizin, N-acetyl cysteine, and glycine, as 50-75 mg three times daily along with desloratadine 5-8.8 mg daily for 4 weeks improves response rate, cure rate, and recurrence rate when compared with desloratadine alone (108571). Another meta-analysis of clinical research in pediatric and adult patients with chronic urticaria shows that taking compound glycyrrhizin 25-75 mg 2-3 times daily improves efficacy rate of symptom reduction, increases cure rate, and decreases recurrence rate when compared with second-generation antihistamine monotherapy (113634). However, most studies included in the meta-analyses were low quality, and all studies were conducted in China. Higher quality studies in other geographic locations are needed to confirm these findings.
• Vitiligo. It is unclear if the licorice constituent compound glycyrrhizin is beneficial for vitiligo. Details: A meta-analysis of 14 clinical studies in patients aged 3-68 years old with vitiligo shows that taking licorice constituent compound glycyrrhizin 25-75 mg 3 times daily for 2-6 months with standard treatment improves effectiveness, cure rate, and immune-mediated inflammatory markers when compared with standard treatment alone (112232). Additionally, a meta-analysis of clinical studies conducted in China in adults with vitiligo suggests that taking oral or intramuscular compound glycyrrhizin for 10 weeks to 6 months in combination with conventional therapies, including phototherapy, immunosuppressants, or traditional Chinese medicine, increases the percentage of patients with more than 50% regimentation when compared with conventional treatments alone (113635). More evidence is needed to rate licorice for these uses.

(Read more about LICORICE)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Atopic dermatitis (eczema). A specific combination product (Zemaphyte, Phytopharm Plc) containing schizonepeta has been evaluated for atopic dermatitis. Although some preliminary clinical research shows that taking this combination product for 8 weeks to 12 months reduces skin lesions when compared to baseline (12627,12628,103902,103903), higher quality clinical research has not supported this finding (12630). In one high-quality, randomized, crossover study in Chinese patients aged 8-52 years, taking this combination product daily for 4 weeks, then twice weekly for 4 weeks, did not improve clinical symptoms when compared with placebo (12630). The combination product evaluated in these studies (Zemaphyte, Phytopharm Plc) contains undisclosed quantities of schizonepeta, Ledeboureilla seseloides, Potentilla chinensis, Aebia clematidis, rehmannia, peony, Lophatherum gracile, Dictamnus dasycarpus, tribulus, and licorice.br> More evidence is needed to rate schizonepeta for this use.

(Read more about SCHIZONEPETA)

POSSIBLY EFFECTIVE

• Breast cancer. High dietary intake of soy might be beneficial for the prevention of breast cancer and breast cancer recurrence in some patients. However, soy supplements do not seem to be beneficial. Details: For prevention, most population research has found that higher dietary intake of soy is associated with up to a 26% reduced odds of developing breast cancer when compared with a lower intake (7335,7336,11038,11807,75377,75587,90955,108251). One meta-analysis of population research found that patients who consumed more than 15 mg soy isoflavones daily made up about 25% of all cases of breast cancer, compared with 75% of cases in the group of patients consuming less than 15 mg daily (108251). The effects appear to vary depending on the ethnicity of the patient. Population research has consistently found that a high-soy diet in Asian and Asian-American females is associated with a significantly reduced risk of breast cancer (7335,7336,11038,11807,75377,75587,90955). However, the amount of soy consumed in a Western diet, even among those who consume the highest amounts of soy, was not found to have a preventative effect (11391,17109,90955,90967). The reason for the disparate findings are unknown but may be related to genetic differences or differences in quantification of soy intake (7663,94153). Also, the prophylactic benefit seems to apply regardless of whether high amounts of soy are consumed during adolescence or later in life (7335,7336,9674). Limited population research has also found that consuming a diet high in soy is associated with up to a 25% reduced risk of breast cancer recurrence; however, it is unclear whether there is an association with reduced mortality in breast cancer patients (90956,90969,94154). The effect appears to be greater for certain subgroups of breast cancer patients. Increased dietary soy intake is associated with a 28% to 36% risk reduction in patients with estrogen receptor (ER)-negative tumors, a 30% risk reduction in patients with ER-positive/progesterone receptor (PR)-positive tumors, and a 25% to 36% risk reduction in postmenopausal patients (90956). Some small clinical studies have also evaluated the use of soy isoflavone extract . One small clinical study in patients with breast cancer shows that taking a soy isoflavone extract 200 mg daily for 2 weeks prior to surgery does not seem to affect cancer cell growth when compared with a historical control (11042). Another small clinical study in patients at high risk for breast cancer or with a history of breast cancer shows that taking a soy tablet containing 50 mg soy isoflavones (Novasoy, Archer Daniels Midland Co.) daily for 12 months does not alter mammographic or breast tissue density when compared with placebo (95999).
• Chronic kidney disease (CKD). Oral soy protein seems to improve some measures of disease severity in patients with CKD. Details: Clinical research shows that consuming soy protein seems to reduce proteinuria in people with kidney disease (2286,2287,2288,75249,75634). Also, a meta-analysis of clinical research in patients with CKD who are not on dialysis shows that soy protein intake reduces serum levels of creatinine by 0.07 mg/dL, phosphorus by 2.5 mg/dL, and triglyceride by 18 mg/dL when compared with placebo or control (90989).
• Diabetes. Diets high in soy seem to reduce the risk of type 2 diabetes. Also, oral soy protein, but not soy isoflavones, seems to modestly improve glycemic indices. It is unclear if soy is beneficial for lowering blood lipid levels or reducing cardiovascular (CVD) mortality risk in adults with type 2 diabetes. Details: A meta-analysis of observational studies has found that higher dietary intake of tofu, soy protein, or soy isoflavones is associated with an 8% to 16% lower risk of developing diabetes when compared with a lower dietary intake (105608). In menopausal patients without diabetes, a meta-analysis of clinical research shows that intake of soy isoflavones 40-161 mg daily seems to improve glycemic indices when compared with control (96423). Some research shows that soy can modestly improve glycemic indices in patients with diabetes. A meta-analysis of small low-quality clinical studies in patients with diabetes or metabolic syndrome shows that taking various formulations of soy protein modestly reduces fasting plasma glucose and insulin levels, as well as insulin resistance, when compared with control (96001). An older meta-analysis assessing both healthy patients and patients with diabetes shows that a whole soy diet reduces fasting blood glucose by about 4 mg/dL when compared with control (75493). Small clinical studies also suggest that an extract of the fermented soybean product, Touchi, acts as an alpha-glucosidase inhibitor. It seems to modestly lower blood glucose, glycated hemoglobin (HbA1c), and triglycerides in patients with type 2 diabetes (11762,75205). However, some conflicting evidence exists. A meta-analysis of small, low-quality clinical studies in patients with type 2 diabetes shows that taking soy isoflavones does not improve glycemic indices when compared with control (105610). Also, another meta-analysis of clinical research in patients with type 2 diabetes shows that taking soy protein and/or soy isoflavones for 6-12 weeks does not improve glycemic indices when compared with either soy protein without isoflavones, other protein, or placebo (105610). Reasons for these conflicting results are unclear but may relate to differences in baseline blood glucose levels, the formulation of soy, or the duration of treatment. Some research shows that soy may modestly improve the lipid profile in patients with diabetes. A meta-analysis of clinical research in patients with diabetes shows that taking soy protein and/or soy isoflavones for 6-12 weeks modestly reduces levels of total and low-density lipoprotein (LDL) cholesterol, but not high-density lipoprotein (HDL) cholesterol or triglycerides, when compared with control (105610). Consuming soy foods might reduce the risk of mortality related to CVD in patients with diabetes. Population research suggests that consuming soy foods at least four days each week is associated with a 23% reduced risk of CVD mortality when compared with never consuming soy foods. Consuming soy foods less than four times weekly is not associated with CVD mortality risk (108242). Soy is also of interest in the prevention or treatment of gestational diabetes. Population research has found that consumption of less than 40 grams of soy daily in the second trimester is associated with a 2.1-fold increased risk of gestational diabetes when compared with daily soy intake of 40 grams or more (108241). Also, a small clinical trial in patients with gestational diabetes shows that consuming a diet containing about 0.3 grams/kg soy protein for 6 weeks, beginning at 24-28 weeks' gestation, reduces blood glucose levels, insulin resistance, and triglyceride levels when compared with consuming a non-soy control diet (95993).
• Diarrhea. Oral soy fiber seems to reduce acute diarrhea in infants, although it may not be beneficial in adults. Details: Giving soy fiber-supplemented formula orally, either alone or in combination with oral rehydration solution, seems to reduce the duration of acute diarrhea in infants when compared with cow's milk formula or oral rehydration solution alone (2291,2292,75474,75517,75523,75531,75572). However, in some studies, a reduction in the duration of acute diarrhea was not observed when compared with cow's milk formula (75522,75542). In adult patients receiving nutrition via intubation, preliminary clinical research suggests that treatment with soy-polysaccharide fiber does not improve the incidence of diarrhea when compared to control (75508).
• Galactosemia. Oral soy protein can be used in infant formula to prevent symptoms of galactosemia. Details: Soy does not contain the sugar galactose. Some research suggests that giving oral isolated soy protein-based formula in place of milk-based formula to infants seems to be helpful for preventing symptoms of galactosemia (3400).
• Hyperlipidemia. Oral soy protein seems to modestly reduce lipid levels. However, purified soy isoflavone may not have the same benefit. Details: Consuming soy protein orally, in place of other dietary protein, seems to modestly reduce total cholesterol and low-density lipoprotein (LDL) cholesterol by about 3% to 4% when compared with control (842,2293,2294,2296,2585,3402,4755,6412,7346,7803)(8530,10459,42059,75356,105598,105604). Additionally, some research shows that soy protein might be more effective in patients with more severe hyperlipidemia (75497). The FDA has approved labeling for specific soy products that states that they may be used for cholesterol reduction in combination with a diet low in saturated fat and cholesterol. To be eligible for this labeling, soy products must provide at least 6.25 grams of soy protein per serving, which is 25% of the effective daily intake (3977). However, not all evidence is positive. Some studies have shown no benefit of soy protein or isoflavones on LDL cholesterol levels when compared to control (8521,9679,12034,17105,53771,75236)(75242,75274,75276). Furthermore, although a few clinical trials have shown significant decreases in triglycerides following supplementation with soy or soy protein isolate (75258,75365), most studies suggest that soy protein does not decrease triglycerides when compared to control (2293,6412,8530,12034,17105). The effect of soy protein on high-density lipoprotein (HDL) cholesterol is inconsistent. Most studies suggest that it does not increase HDL levels (2293,6412,8530,12034,75286)(75524), although some analyses of clinical research suggest that soy might increase HDL cholesterol levels by up to 4% when compared to control (75480,75497). Doses of soy protein have ranged from 25-135 grams daily, providing 40-318 mg daily of isoflavones; however, higher doses do not seem to be more effective (17106,105598). Some evidence suggests that soy protein providing more isoflavones, or supplemented with isoflavones, might be more effective (3402,6413,10459), but this has not been consistently found in studies (3402). Most studies evaluating soy protein products containing little to no isoflavones suggest that these products are not effective (3402,7346,9679); however, purified soy isoflavone supplements alone do not seem to decrease LDL cholesterol (851,4738,7345,8502,10459,14066). In addition to soy protein, limited evidence suggests that soy fiber alone might reduce total cholesterol, LDL cholesterol, and triglyceride levels when compared with placebo (75686,75689). There is also some evidence that ultra-high temperature (UHT) treatment of soy milk destroys any cholesterol-lowering activity (17106).
• Hypertension. Oral soy seems to modestly reduce blood pressure in some patients. Details: A meta-analysis of the available clinical research shows that consuming soy products modestly lowers systolic and diastolic blood pressure by an average of 1.6 mmHg and 1.2 mmHg, respectively, when compared with control (105605). This analysis is limited by high risk of bias and the lack of a dose-response relationship. An older meta-analysis, as well as individual clinical studies, in patients with prehypertension or mild hypertension show that consuming soy protein 18-40 grams, providing 118-143 mg of isoflavones, daily or black soy peptide 4.5 grams daily for 8 weeks reduces systolic blood pressure by about 4-8 mmHg and diastolic blood pressure by about 3-5 mmHg when compared with control (1313990962,90965). In normotensive patients, soy protein does not seem to reduce systolic or diastolic blood pressure (90965).
• Lactose intolerance. Oral soy protein can be used in infant formula to prevent symptoms of lactose intolerance. Details: Providing isolated soy protein-based formula orally to infants is an acceptable alternative to milk-based formulas, especially for infants with symptoms of lactose intolerance (3400).
• Menopausal symptoms. Oral soy seems to reduce hot flashes in patients with menopausal symptoms. Details: Consuming soy protein 15-60 grams, providing 34-100 mg of isoflavones, daily seems to modestly decrease the frequency and severity of hot flashes in some menopausal adults. Improvement seems to be greater in those with a higher frequency of hot flashes at baseline (2296,2297,3978,3986,3987,7653,9917,11805,15220,17110,75478)(75486,75649,92661,95997). Taking concentrated soy isoflavone extracts, providing 35-200 mg of isoflavones, daily seems to have similar effects (4751,6455,7802,9916,10460,11805,11993,11994,13209,15220)(15850,75478,90950,90979,92661). Higher doses of 100-200 mg of isoflavones daily and higher frequency of dosing intervals seem to have greater benefit (90950). Furthermore, the amount of the specific isoflavone genistein contained in a soy product may influence outcomes. According to one analysis, studies using products that provide at least 15 mg of genistein daily consistently show positive outcomes. Studies using products containing a lower concentration of genistein have produced inconsistent findings (15133). Not all research has found that soy extracts reduce hot flashes (7801,11806,14062,15038,15851,16762); some experts speculate that this is due to a high placebo response (9916). Some clinical research has compared soy isoflavone extracts to conventional estrogen replacement. In one study, a concentrated soy isoflavone extract of genistein 54 mg daily reduced hot flashes by 22% to 29%, compared to 54% in those taking 17beta-estradiol as 1 mg daily plus norethisterone acetate 0.5 mg daily (11994). Additional preliminary research suggests that taking a soy isoflavone extract providing 60 mg isoflavones twice daily is comparable in efficacy to conjugated estrogens 0.625 daily for reducing menopausal symptoms. Conjugated estrogens seem to work more quickly; it seems to take up to 2 months to achieve the full effect of soy isoflavones (13209). One clinical trial compared soy isoflavones 10-40 mg daily to S-equol, a soy isoflavone metabolite. Soy isoflavones were less effective for reducing hot flash frequency when compared with S-equol (90960). This has led to some speculation that the effectiveness of soy in relieving hot flashes is influenced by a patient's ability to convert daidzen, a soy isoflavone, to S-equol (90950). It is theorized that patients who are S-equol producers are more likely to achieve symptom relief from soy. However, observational and clinical research does not support this theory (90990,94162). Soy has also been evaluated for the management of other symptoms of menopause. Some clinical research in menopausal patients with depression suggests that taking soy 100 mg, providing 50 mg of soy isoflavones, in combination with sertraline 50 mg daily for three months improves depression severity when compared with sertraline or soy alone (90958). An analysis of two small clinical trials shows that supplemental soy providing 50-118 mg of isoflavones can reduce vaginal dryness scores by 0.26 when compared with control (92661). Also, an open-label study suggests that drinking a specific beverage (ViveSoy) containing soy protein 15 grams and soy isoflavones 50 mg orally daily for 12 weeks reduces overall urogenital symptoms when compared with a control group (95997). However, one small clinical study in perimenopausal patients shows that a soy-rich diet does not relieve urogenital symptoms, including vaginal dryness, itching, and urinary incontinence, when compared with a soy-free diet (75285).
• Metabolic syndrome. Oral soy protein seems to improve glycemic control and other markers of metabolic syndrome. Details: A meta-analysis of clinical research in patients with diabetes or metabolic syndrome shows that following a diet high in soy protein can decrease fasting plasma glucose and insulin levels, as well as insulin resistance, when compared with a control diet. Furthermore, dietary intake of soy protein modestly decreases diastolic blood pressure and low-density lipoprotein (LDL) cholesterol by a small amount in this population, although there is no effect on systolic blood pressure, high-density lipoprotein (HDL) cholesterol, or triglycerides (96001). Other clinical research shows that consuming a soy nut diet or a soy protein diet reduces fasting plasma glucose and LDL cholesterol levels when compared to baseline in postmenopausal adults with metabolic syndrome; however, the soy nut diet seems to more beneficial than either the soy protein diet or a Dietary Approaches to Stop Hypertension (DASH) diet (75378).
• Muscle strength. Oral soy protein seems to increase muscle strength. Details: Overall, soy protein combined with resistance training seems to increase muscle strength when compared with placebo (16748,75246,96942,98871). A meta-analysis of three clinical studies shows that consuming soy protein in addition to resistance training improves strength and lean body mass in untrained athletes (98871). Other clinical research shows that soy also improves muscle strength in trained athletes and postmenopausal adults (75246,96942). One study in Olympic endurance athletes shows that consuming isolated soy protein (Supro) 1.5 grams/kg daily for 8 weeks increases body mass and strength indices and reduces fatigue when compared with no protein supplementation (75246). Clinical research in postmenopausal adults undergoing resistance training 3 days weekly shows that taking soy protein 25 grams daily in skim milk for 16 weeks increases the maximum amount of weight lifted in one repetition by over 80% for both bench press and knee extension when compared to a maltodextrin placebo (96942). Soy protein has also been compared with other protein supplements. A meta-analysis of preliminary clinical studies and other clinical research show that soy protein seems to work as well as whey, beef, and dairy (casein and whey) protein for improving muscle strength (75404,85941,98871,105591). However, the validity of these findings is limited by the small size and high heterogeneity of the studies.
• Osteoporosis. Oral soy isoflavones seem to improve bone density and reduce the risk of osteoporosis in post-menopausal adults. Details: Most clinical research suggests that soy protein or soy extract containing 75-90 mg of isoflavones can increase bone mineral density (BMD), or slow BMD loss, and improve biochemical markers of bone turnover in peri- and postmenopausal adults when compared with control (842,4951,6449,9775,11082,90972,90980). Lower doses of isoflavones do not seem to be as beneficial. However, some observational research in postmenopausal Japanese adults and Chinese females aged 30-40 years has found that consuming about 50 mg dietary soy isoflavones daily is associated with a higher BMD when compared with lower soy isoflavone intake (7342,11081). An observational study in postmenopausal Asian patients has found that consuming higher dietary soy protein is associated with a lower risk of developing fractures when compared with lower amounts (13181). However, not all research has been positive. Some conflicting evidence suggests that soy protein does not improve BMD in some postmenopausal adults. The discrepancy in findings may be due to differences in soy formulations, concomitant treatments, or variable patient populations (4952,12034,14064,90978). For example, most evidence shows that soy does not affect BMD in premenopausal patients or bone turnover in adolescents (7660,8532,9684,11086). It is theorized that only people who can convert daidzein, a soy isoflavone, to S-equol might obtain benefits from soy (4952). However, clinical research suggests that there is no difference in bone calcium retention between equol producers and nonproducers (95995).

POSSIBLY INEFFECTIVE

• Benign prostatic hyperplasia (BPH). Oral soy does not seem to reduce BPH symptoms. Details: Clinical research in patients with BPH shows that taking soy isoflavones 40 mg (Soylife 40, Acatris) daily for 12 months does not improve peak urine flow rate, residual urine volume, symptoms of BPH, or general quality of life when compared with placebo (90983).
• Breast cancer-related hot flashes. Oral soy does not seem to reduce the risk for breast cancer-related hot flashes. Details: Clinical research shows that consuming a soy beverage providing soy isoflavones 90 mg daily or taking a soy extract providing soy isoflavones 50 mg three times daily does not reduce hot flashes in breast cancer survivors (3991,7658,8499). Observational research in breast cancer survivors has also found no association between hot flash incidence and soy isoflavone consumption (105602).
• Colorectal cancer. Oral soy does not seem to reduce the risk for colorectal cancer. Details: Some observational research from China and Japan has found that intake of soy protein or soy isoflavone is not associated with the risk of developing colorectal cancer (105601). Furthermore, some clinical research shows that soy protein powder 58 grams containing isoflavones 83 mg, taken daily for 12 months, does not reduce the proliferation of colorectal epithelial cells in patients with adenomatous polyps when compared to control (75282).
• Exercise-induced muscle soreness. Oral soy does not seem to reduce muscle soreness after exercise. Details: Some clinical research shows that taking soy isoflavone extract 120 mg orally for 30 days prior to exercise doesn't ameliorate muscle soreness caused by exercise when compared with placebo (8524).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alzheimer disease. It is unclear if oral soy improves cognition in patients with Alzheimer disease. Details: Preliminary clinical research in patients with Alzheimer disease shows that taking soy isoflavones (Novasoy, Archer Daniels Midland Co.) 100 mg daily for 6 months does not improve cognition when compared with placebo (96424).
• Androgen deprivation therapy (ADT)-associated hot flashes. One small clinical study in patients with prostate cancer receiving ADT shows that taking soy protein powder 20 grams, providing 160 mg of isoflavones, alone or along with venlafaxine 75 mg, once daily for 12 weeks does not improve the severity of hot flash symptoms when compared with milk protein, with or without venlafaxine (90981).
• Asthma. It is unclear if oral soy reduces asthma symptoms. Details: One population study has found that people with asthma who consume soy foods providing more than 250 mcg of genistein for every 1000 kcal consumed (e.g., 500 mcg/day for 2000 kcal diet) daily have increased lung function, as measured by FEV1 scores, when compared to those who consume less (11084). However, clinical research in adult and pediatric patients with poorly controlled asthma shows that taking soy isoflavones 50 mg twice daily for 24 weeks does not improve FEV1 scores, reduce the number of asthma episodes, or improve asthma symptoms when compared with placebo (90977).
• Cardiovascular disease (CVD). It is unclear if soy consumption reduces the risk for CVD or CVD-related mortality. More research is needed to determine whether certain populations may benefit from increased soy intake. Details: Due to mixed findings, it is unclear if consuming soy is associated with a reduced risk of CVD events. One population study has found that consuming at least 60 grams of soy daily over a 12-month period is associated with a 14% reduced risk of having a CVD event over the next 5 years, as well as a reduced risk of stroke, when compared with consuming less than 15 grams daily (108253). A study in Japan has found that consuming soy five or more times per week over a 10-year period is associated with fewer adverse cardiovascular outcomes in only a certain subset of patients when compared with consuming soy twice a week or less. Postmenopausal adults with the highest consumption had a 36% lower risk of stroke, a 45% lower risk of myocardial infarction, and a 65% lower risk of CVD mortality. However, risk was not significantly reduced in males or premenopausal adults (17108). In contrast, a study in Korea has found that consuming a median of 16.5 servings of soy per week is associated with a 64% reduced risk of CVD incidence in premenopausal, but not postmenopausal, adults when compared with a median of 4.7 servings per week. A subgroup analysis has found that the highest intake of tofu, but not soybeans, fermented soy paste, or soy milk, is associated with a reduced incidence of CVD (108243). Additionally, higher dietary intake of soy does not seem to be associated with a reduced risk of cardiovascular events in Western females (13040). The amount of phytoestrogens typically consumed in Western diets is significantly lower than the amount typically consumed in Asian diets. The form of soy food and isoflavone content might play a role in these discrepancies. Any association between consumption of soy-containing foods and CVD mortality is also unclear. A meta-analysis of observational studies conducted in China or Japan has found that the highest intake of soy-containing foods is not associated with a lower risk of CVD-related mortality when compared with the lowest intake (96941). A population study in patients with or without a prior history of CVD has also found that soy-containing food consumption is not associated with a lower risk of CVD-related mortality when compared with the lowest intake (108244). However, some research has found a positive effect of soy consumption on CVD mortality risk. A subgroup analysis of a meta-analysis has found that the highest intake of fermented soy products is associated with a 16% reduced risk of CVD mortality; higher intake of non-fermented soy is not associated with CVD mortality (96941). Population research in patients without a prior history of CVD has found that soy-containing food consumption is associated with a lower risk of myocardial infarction-related mortality when compared with the lowest intake (108244). Also, one population study in adults with type 2 diabetes has found that consuming soy-containing foods at least four days each week is associated with a 23% reduced risk of CVD mortality when compared with never consuming soy foods. Consuming soy foods less than four times weekly is not associated with CVD-related mortality (108242).
• Cervical cancer. It is unclear if oral soy reduces the risk for cervical cancer. Details: Population research has found that the highest dietary intake of soy over approximately 17 years is associated with a 57% decreased risk of cervical cancer when compared to the lowest intake of soy in females who also drank green tea. However, neither soy intake nor green tea intake alone was associated with a decreased risk of cervical cancer. Additionally, other population research has not confirmed an association between soy intake and cervical cancer (101800).
• Child growth. It is unclear if oral soy protein enhances child growth. Details: Preliminary clinical research in Colombian children 2-7 years of age shows that consuming a soy protein supplement dissolved in fruit juice on 6 days of every week for 1 year does not improve body mass index, body composition, weight, or height when compared with consuming fruit juice and whole milk. A sub-analysis shows that children consuming the soy protein supplement had an increase in weight-for-age when compared with the control group, indicating that the supplement may be beneficial for ensuring adequate weight and nutritional status during prepubertal growth (100320). However, the children in this study had normal or below average weight-for-age at baseline, limiting the applicability of these findings to other patient populations.
• Cognitive function. It is unclear if oral soy improves cognitive function; research is conflicting. Details: Some research shows that college students who increase consumption of soy foods providing isoflavones 100 mg daily have improved short- and long-term memory (9671). Postmenopausal patients aged 50-65 years who take a soy extract supplement providing isoflavones 60 mg daily also seem to have some improvement in some measures of cognitive function (12048). There is also evidence in postmenopausal patients aged 55-75 years that taking a soy extract supplement providing isoflavones 110 mg daily might improve verbal memory scores (12040). However, another study in this population shows that consuming 25.6 grams daily of soy protein providing 99 mg of isoflavones does not improve cognitive function (12034). Similarly, population research in females aged 42-52 years has found that increasing dietary intake of the isoflavones genistein and daidzein is not associated with improved measures of cognitive function (15042). These differing findings might be explained by variations in study design and soy formulations.
• Cognitive impairment. Oral soy has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults 55 years of age and older with mild cognitive impairment shows that taking a specific combination product (DW2009) containing fermented soybean powder and Lactobacillus plantarum daily for 12 weeks modestly improves composite cognitive function when compared with placebo (100319). It is not clear if this effect is due to soy, lactobacillus, or the combination.
• Colic. It is unclear if oral soy is beneficial in infants with colic. Details: Preliminary clinical research shows that consuming soy-based formula might reduce the duration of colic symptoms in infants with cows' milk intolerance (75509,75543). However, other clinical research shows that consuming soy-based formula does not improve crying in infants with colic when compared with dicyclomine hydrochloride 3 mg/kg daily (75573). Also, a meta-analysis of only high quality clinical research shows that soy milk formula does not improve the persistence of colic or the duration of crying in infants with colic when compared with control (75611).
• Crohn disease. It is unclear if oral soy improves symptoms of Crohn disease. Details: A small observational study in patients with inactive Crohn disease has found that taking oral soy-derived protein in combination with enteral treatment for 4 weeks is associated with increased bowel movements, improved symptoms such as fatigue and mental strain, and increased body weight when compared with standard enteral treatment alone (75175).
• Diabetic nephropathy. It is unclear if oral soy improves kidney function in patients with diabetic nephropathy. Details: A meta-analysis of small clinical trials in patients with diabetic nephropathy shows that consuming soy products, such as soy protein and soy milk, modestly reduces proteinuria and blood urea nitrogen (BUN), as well as levels of total and low-density lipoprotein (LDL) cholesterol, triglycerides, and fasting blood glucose, when compared with animal protein or cow's milk. However, there was no effect on any measures of kidney function (108247). Some individual small clinical trials show that replacing dietary animal protein with soy protein reduces urinary albumin excretion in patients with diabetic nephropathy (7348,12555,12556). However, one small clinical study shows that consuming soy milk 240 mL daily for 4 weeks does not affect urinary creatinine, blood urea nitrogen, proteinuria, or glomerular filtration rate in patients with diabetic nephropathy (90966).
• Dyspepsia. Oral soy protein has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in adults with mild or moderate dyspepsia shows that consuming 1 gram of toasted soy flour fermented with Lactobacillus delbrueckii up to three times daily for 3 weeks does not improve heartburn severity or frequency when compared with placebo (105599).
• Endometrial cancer. It is unclear if oral soy protein reduces the risk for endometrial cancer. Details: Most epidemiological research has found that increased soy intake is associated with a lower risk of endometrial cancer. Endometrial cancer incidence is lower in Japan, China, and other Asian countries where the typical diet is low in calories and high in soy, whole grain foods, vegetables, and fruits (7338,11036,90954). Also, a large meta-analysis of population research has found that the highest total and fermented soy intake is associated with a 17% to 19% reduced risk of developing endometrial cancer when compared to the lowest intakes in postmenopausal adults (96002). However, one clinical study shows that taking soy protein 25 grams daily providing 91 mg of aglycon equivalents of isoflavones and glycosides for three years does not reduce the risk of endometrial hyperplasia or cancer when compared with placebo in postmenopausal adults. However, this study may not have been adequately powered to detect small differences in the low rates of endometrial hyperplasia (90971).
• Fibromyalgia. It is unclear if oral soy reduces fibromyalgia symptoms. Details: Clinical research shows that consuming a shake containing soy protein 20 grams and soy isoflavone 160 mg once daily for 6 weeks does not improve physical functioning or symptoms of depression in patients with fibromyalgia when compared with placebo (75451).
• Gastric cancer. It is unclear if oral soy reduces the risk for gastric cancer. Details: Meta-analyses of population research have found that the highest intake of soy-containing foods and nonfermented soy products is associated with a 21% to 37% decreased risk of gastric cancer when compared with the lowest intake (95998,108246). Intake of at least 100 grams daily of nonfermented soy foods was found to be the most protective (95998). However, a high intake of fermented soy products is associated with an increased risk of gastric cancer, and intake of 1-5 cups daily of the fermented soy product miso soup is associated with an increased risk of gastric cancer in males (95998,108246).
• Hepatitis C. It is unclear if oral soy is beneficial for hepatitis C. Details: Preliminary clinical research in patients with hepatitis C shows that taking soy protein 32 grams daily for 12 weeks reduces the number of cases of steatosis by 47% and reduces alanine aminotransferase (ALT) levels by 13% when compared to baseline. However, it is no different than taking casein protein (90970).
• Irritable bowel syndrome (IBS). A small study suggests that oral soy isoflavones might reduce IBS symptoms. Details: A small clinical study in females with IBS shows that taking soy isoflavones 40 mg daily for 6 weeks improves symptoms of IBS, such as abdominal distention and abdominal pain severity and duration, by approximately 27% when compared with placebo. Quality of life is also improved. Some symptoms are also improved when soy isoflavones are taken in combination with vitamin D; however, the combination of soy isoflavones and vitamin D does not seem to improve symptoms better than soy isoflavones alone (96425).
• Lung cancer. It is unclear if dietary soy reduces the risk for lung cancer. Details: A meta-analysis of epidemiological research has found that although increased soy intake is not associated with a reduced risk of lung cancer overall, it is associated with a slightly reduced risk in nonsmoking adults (90985).
• Mastalgia. It is unclear if oral soy is beneficial for mastalgia. Details: A small clinical study suggests that soy milk providing 34 grams soy protein daily might reduce cyclical breast pain when compared with no intervention (2428).
• Migraine headache. Oral soy has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking a combination of soy isoflavones 60 mg, dong quai 100 mg, and black cohosh 50 mg daily for 24 weeks reduces the frequency of menstrual-associated migraine attacks when compared with placebo (35797). It is not clear if this effect is due to soy, the other ingredients, or the combination.
• Neonatal jaundice. It is unclear if oral soy reduces the risk of neonatal jaundice. Details: Clinical research shows that patients with gestational diabetes who consume a diet containing soy protein along with other plant and animal proteins for 6 weeks beginning at 24-28 weeks' gestation have a 73% reduced risk for newborn hyperbilirubinemia when compared with those consuming a control diet containing only non-soy plant and animal proteins (95993).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral soy is beneficial for the treatment or prevention of NAFLD. Details: Observational research in a Chinese population has found that increased frequency of dietary soy consumption is associated with a lower incidence of NAFLD when compared with lower consumption (105612). A meta-analysis of three small clinical trials in patients living in Iran with NAFLD shows that consuming soy milk, soy foods, or a genistein supplement for 8 weeks might reduce some liver transaminase levels when compared with control (105611). Another meta-analysis of small clinical trials in patients with NAFLD shows that consuming soy milk, soy foods, or a genistein supplement for 8 or 24 weeks modestly improves insulin resistance but does not improve body mass index, cholesterol levels, or liver transaminase levels (108239). These analyses are limited by their generally small population size and the heterogeneity of interventions.
• Obesity. It is unclear if consuming oral soy protein as part of a calorie-restricted diet improves weight loss; research is conflicting. Details: Some clinical research shows that consuming soy protein in conjunction with calorie restriction for 2-6 months helps reduce weight in those who are obese and overweight when compared with calorie restriction alone (11085,75397). Other clinical research shows that consuming soy protein for 16 weeks improves weight loss in overweight females when compared with consuming protein from meat (75620). Also, consuming black soy peptide 4.5 grams daily for 12 weeks reduces body weight and body fat mass more than placebo in overweight and obese adults (90961). In addition, some clinical evidence shows that eating biscuits supplemented with soy fiber 100 grams daily for 12 weeks reduces body weight, body mass index (BMI), and low-density lipoprotein (LDL) cholesterol when compared to control in overweight and obese patients (90960). However, contradictory evidence exists. Some clinical research shows that following a calorie-restricted diet and consuming soy-based meal replacements 3-5 times daily for 12-16 weeks, or eating soy protein-rich foods in place of animal protein for 2-12 weeks, does not improve weight loss in overweight or obese individuals when compared to a calorie-restricted diet alone (75277,75372,75376,90968). Also, in overweight and obese females following a free-choice diet, soy protein 56 grams daily for 23 weeks does not appear to improve weight loss when compared to eating an isoenergetic amount of carbohydrates (86077). Finally, a subgroup analysis of six preliminary clinical trials shows that soy products do not improve weight loss in postmenopausal adults (98870). The reason for these disparate findings is unclear but may be due to differences in the soy products used or differences in patient population. For example, a meta-analysis of clinical research shows that phytoestrogen consumption reduces weight in healthy postmenopausal adults but not in those with comorbid conditions (98870). However, the clinical validity of this analysis is limited because it did not evaluate the effect of soy-only phytoestrogens. Soy protein has also been compared with whey protein. One small clinical study in overweight and obese adults shows that patients taking soy protein isolate 52 grams for 23 weeks had similar overall weight and fat loss as those taking whey protein concentrate 52 grams daily (86077). In contrast, another small clinical study in overweight males shows that taking soy isolate 60 grams before lunch daily for 12 weeks is less effective for weight loss when compared with taking whey protein concentrate 65 grams (91801).
• Osteoarthritis. It is unclear if oral soy protein reduces osteoarthritis pain. Details: Preliminary clinical research shows that taking soy protein 40 grams daily for three months improves range of motion, pain, and quality of life in osteoarthritis patients, particularly males, when compared to baseline. However, these beneficial effects seem to also be observed following supplementation with milk-based protein, indicating that the benefits may have resulted from a placebo effect (75266).
• Overall mortality. It is unclear if dietary soy reduces overall mortality; the available research is conflicting. Details: A meta-analysis of observational studies has found that the highest intake of soy products is not associated with a lower risk of overall mortality, mortality from cardiovascular disease, or mortality from cancer when compared with the lowest intake (96941). However, a more recent population study has found that consuming at least 60 grams of soy daily over a 12-month period is associated with a 17% reduced risk of overall mortality over the next 5 years when compared with consuming less than 15 grams daily (108253). Also, an observational study in Japanese patients followed over 14.8 years has found that although overall soy intake is not associated with any benefit, increased intake of fermented soy products, such as natto and miso, was found to be associated with a slightly reduced risk of mortality (105600).
• Polycystic ovary syndrome (PCOS). It is unclear if oral soy reduces PCOS symptoms. Details: Clinical research shows that taking soy isoflavones 50 mg daily for 12 weeks improves insulin levels and insulin resistance by a small amount when compared with placebo in patients with PCOS. Furthermore, taking soy isoflavones improves the free androgen index by approximately 25% and triglyceride levels by 14% when compared to baseline. However, taking soy isoflavones does not improve low- or high-density lipoprotein (LDL or HDL) cholesterol levels or markers of inflammation (95994).
• Postmenopausal conditions. It is unclear if oral soy is beneficial for postmenopausal conditions. Details: A meta-analysis of generally small clinical trials in postmenopausal adults shows that taking soy protein with isoflavones or soy isoflavones, usually for 3-24 months, has modest beneficial effects on total cholesterol, and possibly high-density lipoprotein (HDL) cholesterol, when compared with milk protein, soy protein without isoflavones, or placebo. However, there was no effect on low-density lipoprotein (LDL) cholesterol or triglyceride levels. Subgroup analyses show that reductions in LDL cholesterol levels occur when soy is used for less than 6 months, in individuals older than 55 years, and when the soy protein contains isoflavones (108249).
• Preterm labor. It is unclear if oral soy reduces the risk for preterm labor. Details: Clinical research in patients with gestational diabetes shows that consuming a diet containing soy protein along with other plant and animal proteins for 6 weeks, beginning at 24-28 weeks' gestation, does not reduce the likelihood for caesarean section, preterm delivery, or maternal hospitalization when compared with a control diet containing only non-soy plant and animal proteins (95993).
• Premenstrual syndrome (PMS). It is unclear if oral soy reduces PMS symptoms. Details: Preliminary clinical research in patients with PMS shows that taking isolated soy protein containing soy isoflavones 68 mg daily for two menstrual cycles reduces cramps and swelling when compared with placebo (75279).
• Prostate cancer. It is unclear if oral soy is beneficial for the treatment or prevention of prostate cancer; research is conflicting. Details: Observational and clinical research has evaluated the effects of soy intake on prostate cancer risk. Observational research has found that consuming an Asian diet, which contains 10 times more soy than the average American diet, is associated with a lower risk of prostate cancer; however, it is unclear whether it is the soy content of the diet or if genetic differences or environmental factors such as fat ingestion are responsible for this correlation (2298,12884,12886,12887). A meta-analysis of observational trials from North America, Europe, and Asia has found that highest intake of total soy foods, unfermented soy foods, or soy isoflavones is associated with a reduced risk of prostate cancer when compared with the lowest intakes. However, higher intake of fermented soy foods is not associated with a reduced risk (96939). Furthermore, some observational research in Japanese males has found a weak association between increased prostate cancer mortality and a higher dietary intake of soy isoflavones when compared with a lower intake (105607). Research evaluating the use of soy supplements is also conflicting. One clinical study shows that taking soy protein 40 grams daily for 6 months reduces the development of prostate cancer six-fold in those at risk of prostate cancer when compared with milk protein (75432). However, another clinical study in healthy adults aged 50-80 years shows that taking soy protein, providing 83 mg isoflavones, daily for a year does not affect PSA levels when compared with a soy protein drink without isoflavones (12888). Soy products have also been evaluated in patients with prostate cancer. One clinical study shows that consuming a specific bread containing 50 grams of soy, providing 117 mg isoflavones, reduces PSA levels after about 3 weeks of treatment when compared with control (13140). Other preliminary clinical research in patients with rising PSA levels following prior therapy for prostate cancer shows that consuming 8 ounces of soy milk, standardized to contain 47 mg isoflavones, three times daily for 12 months slows the increase in PSA levels from 56% to 20% when compared with baseline (75435). However, one clinical study shows that taking soy protein 40 grams daily for 6 months does not reduce prostate size or improve PSA levels in those diagnosed with prostate cancer when compared with milk protein (75432). Also, in those with early stage prostate cancer, consuming a soy beverage daily providing genistein 60 mg does not seem to affect risk factors for progression of prostate cancer, including testosterone, estradiol, PSA, and sex hormone binding globulin (SHBG) levels (11033). Furthermore, consuming soy protein isolate 20 grams standardized to contain approximately 70 mg isoflavones daily for two years does not prevent prostate cancer recurrence following radical prostatectomy when compared with placebo (90953). Reasons for the discrepancies are not entirely clear, but may include the relatively short trial durations (up to 12 months) and heterogeneity of soy preparations and dosing regimens.
• Rheumatoid arthritis (RA). It is unclear if oral soy reduces RA symptoms. Details: Preliminary clinical research in patients with RA shows that consuming a liquid diet containing hydrolyzed soy protein (Top Up) daily for 4 weeks does not improve pain intensity, morning stiffness, or joint swelling and tenderness when compared to consuming a normal daily diet (75619).
• Sarcopenia. It is unclear if oral soy reduces age-related muscle loss; evidence is conflicting. Details: Some clinical research in postmenopausal adults shows that consuming soy protein containing isoflavones 99 mg daily for 12 months does not improve hand grip strength or physical performance when compared with a milk protein placebo (75283). However, another small clinical study in older adults with low muscle mass living in China shows that taking soy, or a whey-soy blended protein, 16 grams daily for 6 months, slightly attenuates muscle loss when compared with no intervention (105603).
• Stroke. It is unclear if oral soy improves outcomes and overall function in people who have had a stroke. Details: One small clinical study shows that older adults with a history of stroke who consumed soy milk 500 mL daily while participating in a rehabilitation program had greater improvements in hand grip strength, 8-feet walking speed, walking performance, and 6-minute walk test after 8 weeks when compared with placebo. However, consuming soy milk did not lead to greater improvements in lean mass or overall short physical performance battery (SPPB) scores when compared with placebo (100321).
• Thyroid cancer. It is unclear if dietary soy reduces the risk for thyroid cancer. Details: Epidemiological research has found that high dietary intake of soy is associated with a reduced risk of thyroid cancer when compared with lower intake (7662,12041).
• Vaginal atrophy. It is unclear if topical soy improves vaginal atrophy. Details: A small clinical study in postmenopausal adults with vaginal atrophy shows that applying one gram of soy extract 4% vaginal gel daily for 12 weeks reduces vaginal dryness and pain during sexual intercourse and improves vaginal endometrial thickness when compared with placebo (90964).
• Wrinkled skin. Small studies suggest that oral and topical soy might reduce wrinkles. Details: A small clinical study in middle-aged females shows that consuming soy isoflavone 40 mg daily for 12 weeks improves skin elasticity and the appearance of fine wrinkles when compared with placebo (75388). Another small clinical study in females with photodamaged skin shows that applying a soy moisturizer containing soybean trypsin inhibitor and Bowman-Birk protease inhibitor (Aveeno Positively Radiant Daily Moisturizer, Johnson & Johnson CCI) twice daily for 12 weeks improves skin pigmentation, fine lines, texture, tone, and appearance when compared with a placebo moisturizer (75410). More evidence is needed to rate soy for these uses.

(Read more about SOY)

LIKELY EFFECTIVE

• Mosquito repellent. Applying soybean oil 2% (Bite Blocker, HOMS LLC) to the skin provides complete protection against mosquitoes for up to approximately 1.5 hours. This is comparable to products containing DEET 4.7%. However, higher concentrations of DEET have a significantly longer duration of action (13077). DEET 10% to 35% provides 4-12 hours of protection depending on the product formulation (13077,13083). Health Canada considers soybean oil to be an alternative to low concentration DEET for protection against mosquitoes with the caveat that soybean oil is considerably shorter-acting (13083,93685).

POSSIBLY EFFECTIVE

• Hypercholesterolemia. Clinical research suggests that consuming soybean oil has modest beneficial effects on levels of total and low-density lipoprotein (LDL) cholesterol when compared with palm oil products. The effect on levels of high-density lipoprotein (HDL) cholesterol is unclear. Preliminary clinical research in adults with normal and high cholesterol shows that adding 20 grams of a soybean oil-based mayonnaise to the diet daily for 2 weeks decreases total cholesterol by 10 mg/dL and LDL cholesterol by 7 mg/dL when compared with using palm olein-based mayonnaise. However, high-density lipoprotein (HDL) cholesterol is also decreased by 5 mg/dL (93684). In young, healthy adults without hyperlipidemia, a small clinical study shows that consuming soybean oil as 20% of total energy intake modestly reduces total and LDL cholesterol levels when compared with palm olein, with no effect on triglyceride or HDL cholesterol levels (108255). However, a small clinical trial in middle-aged and elderly females at increased cardiovascular risk shows that cooking food in soybean oil for 3 months does not improve levels of triglycerides or total or LDL cholesterol when compared with baseline or other oils including olive oil or camellia seed oil (108257). In adults with moderately elevated LDL cholesterol, a small clinical trial evaluated the effects of consuming foods containing either high-oleic soybean oil (50:50 blend of Vistive Gold; Monsanto Company and Plenish; Pioneer) or a mixture of high-oleic soybean oil and fully hydrogenated soybean oil in an 80:20 ratio, providing about 17% of total daily energy intake, for 28 days. Both of these interventions reduce levels of total and LDL cholesterol by 9% to 11% when compared with a blend of palm oil and palm kernel oil. However, foods containing the soybean oil blend also reduced HDL cholesterol levels by 6%; this reduction did not occur with foods containing high-oleic soybean oil alone (108254).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Cancer-related fatigue. Preliminary clinical research in patients with breast cancer shows that taking soybean oil 6 grams daily for 6 weeks modestly reduces some measures of cancer-related fatigue when compared with baseline, fish oil, or a combination of fish oil and soybean oil (108258).
• Coronary heart disease (CHD). In 2017, the US Food and Drug Administration (FDA) determined that it would allow a qualified health claim stating that consuming 1.5 tablespoons of soybean oil per day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of CHD. However, the FDA has concluded that this claim is based on supporting, rather than conclusive, evidence (102361). In addition, the FDA allows for a qualified health claim that using high-oleic acid soybean oil as a replacement for dietary fats and oils higher in saturated fat may reduce the risk of CHD. To achieve this benefit, high-oleic acid soybean oil should not increase total daily energy intake. The suggested daily dietary intake is about 20 grams (1.5 tbsp) of high-oleic soybean oil in place of other fats and oils (98563). More evidence is needed to rate soybean oil for these uses.

(Read more about SOYBEAN OIL)

LIKELY SAFE ...when used in amounts commonly found in foods (12659,12660). Burdock root is commonly eaten as a vegetable (37422,92153,92154)

POSSIBLY SAFE ...when used topically, short-term. An emulsion containing burdock fruit extract 1.2% has been safely applied to the face twice daily for 4 weeks (37420). There is insufficient reliable information available about the safety of burdock when used orally in supplemental doses.

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about BURDOCK)

POSSIBLY SAFE ...when the oil is used orally and appropriately (2). ...when used topically and appropriately (2). There is insufficient reliable information available about the safety of Japanese mint for its other uses.

CHILDREN: LIKELY UNSAFE
when the oil is used topically on the faces of infants and children, particularly in the nasal area. It has been reported to trigger glottal or bronchial spasm, asthma-like attacks, or even respiratory failure (2). There is insufficient reliable information available about the safety of Japanese mint when used orally in children; avoid using.

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about JAPANESE MINT)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Licorice has Generally Recognized as Safe (GRAS) status in the US (4912).

POSSIBLY SAFE ...when licorice products that do not contain glycyrrhizin (deglycyrrhizinated licorice) are used orally and appropriately for medicinal purposes. Licorice flavonoid oil 300 mg daily for 16 weeks, and deglycyrrhizinated licorice products in doses of up to 4.5 grams daily for up to 16 weeks, have been used with apparent safety (6196,11312,11313,17727,100984,102960). ...when licorice products containing glycyrrhizin are used orally in low doses, short-term. Licorice extract 272 mg, containing glycyrrhizin 24.3 mg, has been used daily with apparent safety for 6 months (102961). A licorice extract 1000 mg, containing monoammonium glycyrrhizinate 240 mg, has been used daily with apparent safety for 12 weeks (110320). In addition, a syrup providing licorice extract 750 mg has been used twice daily with apparent safety for 5 days (104558). ...when applied topically. A gel containing 2% licorice root extract has been applied to the skin with apparent safety for up to 2 weeks. (59732). A mouth rinse containing 5% licorice extract has been used with apparent safety four times daily for up to one week (104564).

POSSIBLY UNSAFE ...when licorice products containing glycyrrhizin are used orally in large amounts for several weeks, or in smaller amounts for longer periods of time. The European Scientific Committee on Food recommends that a safe average daily intake of glycyrrhizin should not exceed 10 mg (108577). In otherwise healthy people, consuming glycyrrhizin daily for several weeks or longer can cause severe adverse effects including pseudohyperaldosteronism, hypertensive crisis, hypokalemia, cardiac arrhythmias, and cardiac arrest. Doses of 20 grams or more of licorice products, containing at least 400 mg glycyrrhizin, are more likely to cause these effects; however, smaller amounts have also caused hypokalemia and associated symptoms when taken for months to years (781,3252,15590,15592,15594,15596,15597,15599,15600,16058)(59731,59740,59752,59785,59786,59787,59792,59795,59805,59811)(59816,59818,59820,59822,59826,59828,59849,59850,59851,59867)(59882,59885,59888,59889,59895,59900,59906,97213,110305). In patients with hypertension, cardiovascular or kidney conditions, or a high salt intake, as little as 5 grams of licorice product or 100 mg glycyrrhizin daily can cause severe adverse effects (15589,15593,15598,15600,59726).

PREGNANCY: UNSAFE
when used orally. Licorice has abortifacient, estrogenic, and steroid effects. It can also cause uterine stimulation. Heavy consumption of licorice, equivalent to 500 mg of glycyrrhizin per week (about 250 grams of licorice per week), during pregnancy seems to increase the risk of delivery before gestational age of 38 weeks (7619,10618). Furthermore, high intake of glycyrrhizin, at least 500 mg per week, during pregnancy is associated with increased salivary cortisol levels in the child by the age of 8 years. This suggests that high intake of licorice during pregnancy may increase hypothalamic-pituitary-adrenocortical axis activity in the child (26434); avoid using.

LACTATION:
Insufficient reliable information available; avoid using.

(Read more about LICORICE)

POSSIBLY UNSAFE ...when used orally in excessive amounts. Schizonepeta contains pulegone, a known hepatotoxin (12620,12626).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about SCHIZONEPETA)

LIKELY SAFE ...when soy protein is used orally and appropriately. Soy protein products in doses up to 60 grams, providing up to 185 mg isoflavones, daily have been safely used in studies lasting up to 16 weeks (842,2293,2294,2296,3025,3402,3977,4755,6412,8530)(10372,11805).

POSSIBLY SAFE ...when soy extracts are used orally and appropriately, short-term. Soy extracts containing concentrated isoflavones in doses of 35-120 mg daily have been used with apparent safety for up to 6 months (4751,6455,7802,12040,12048,13209,95994,95999).

CHILDREN: LIKELY SAFE
when consumed in amounts commonly found in foods or as a component of infant formula (3400,4912,7331). Soy milk that's not designed for infants should not be used as a substitute for infant formula. Regular soy milk can lead to nutrient deficiencies (12045). Most evidence shows that exposure to soy formula or other soy products in infancy does not cause early onset of puberty or health or reproductive problems later in life (7331,11080,108245). However, some small cohort studies have suggested that higher soy intake during childhood may be associated with an increased risk of precocious puberty (108240) and may be weakly correlated with the development of breasts in children less than 2 years of age (75520). This is in contrast to an observational study in Chinese children ages 7-9 years which suggests that higher soy intake is associated with delayed puberty (108252). One small cohort study has also found that use of soy infant formula may be associated with an increased risk of endometriosis in adulthood, although endometriosis was also correlated with prematurity, which may have confounded the findings (101803).

CHILDREN: POSSIBLY UNSAFE
when used orally as an alternative to cow's milk in children with severe milk allergy (75359). Although soy protein-based infant formulas are often promoted for children with milk allergy, children with a severe allergy to cow's milk are also frequently sensitive to soy protein (9883). There is insufficient reliable information available about the safety of soy products when used in amounts higher than typical food quantities for children.

PREGNANCY: LIKELY SAFE
when used orally in amounts commonly found in foods (4912).

PREGNANCY: POSSIBLY UNSAFE
when used orally in medicinal amounts. Soy contains mildly estrogenic constituents (3373,3988,3989,3990,3994,6029,75303). Theoretically, therapeutic use of soy might adversely affect fetal development; avoid using.

LACTATION: LIKELY SAFE
when used orally in amounts commonly found in foods (4912). A single 20-gram dose of roasted soybeans, containing 37 mg isoflavones, produces four to six times less isoflavones in breast milk than provided in a soy-based infant formula (2290). There is insufficient reliable information available about the safety of long-term use of therapeutic amounts of soy during lactation.

(Read more about SOY)

LIKELY SAFE ...when used orally in amounts commonly found in foods. ...when used topically and appropriately. Health Canada considers soybean oil to be a safe alternative to low-dose DEET products when used topically as a mosquito repellent (13083,93685). There is insufficient reliable information available about the safety of soybean oil when used orally in medicinal amounts.

PREGNANCY: LIKELY SAFE
when used orally in amounts commonly found in foods. There is insufficient reliable information available about soybean oil when used orally in medicinal amounts; avoid using in amounts greater than those typically found in foods.

LACTATION: LIKELY SAFE
when used orally in amounts commonly found in foods. There is insufficient reliable information available about soybean oil when used orally in medicinal amounts; avoid using in amounts greater than those typically found in foods.

(Read more about SOYBEAN OIL)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking burdock with anticoagulant or antiplatelet drugs might increase the risk of bleeding.  Details In vitro research shows that lignans from burdock reduce rabbit platelet aggregation by inhibiting platelet activating factor (12619). This interaction has not been reported in humans.

(Read more about BURDOCK)

(Read more about FORSYTHIA)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, honeysuckle might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.  Details In vitro research shows that polyphenols extracted from honeysuckle can inhibit platelet aggregation (12610).

(Read more about HONEYSUCKLE)

(Read more about JAPANESE MINT)

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, licorice might reduce the effects of antihypertensive drugs.  Details In human research, licorice increases blood pressure in a dose-dependent manner (1372,7620,59877).

CISPLATIN (Platinol-AQ) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might reduce the effects of cisplatin.  Details In animal research, licorice diminished the therapeutic efficacy of cisplatin (59763).

CORTICOSTEROIDS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of licorice and corticosteroids might increase the side effects of corticosteroids.  Details Case reports suggest that concomitant use of licorice and oral corticosteroids, such as hydrocortisone, can potentiate the duration of activity and increase blood levels of corticosteroids (3252,12672,20040,20042,48429,59756). Additionally, in one case report, a patient with neurogenic orthostatic hypertension stabilized on fludrocortisone 0.1 mg twice daily developed pseudohyperaldosteronism after recent consumption of large amounts of black licorice (108568).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might decrease the levels and clinical effects of CYP1A2 substrates.  Details In vitro research shows that licorice induces CYP1A2 enzymes (111404).

CYTOCHROME P450 2B6 (CYP2B6) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase levels of drugs metabolized by CYP2B6.  Details In vitro research shows that licorice extract and glabridin, a licorice constituent, inhibit CYP2B6 isoenzymes (10300,94822). Licorice extract from the species G. uralensis seems to inhibit CYP2B6 isoenzymes to a greater degree than G. glabra extract in vitro (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2B6; however, these interactions have not yet been reported in humans.

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase levels of drugs metabolized by CYP2C19.  Details In vitro, licorice extracts from the species G. glabra and G. uralensis inhibit CYP2C19 isoenzymes in vitro (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2C19; however, this interaction has not yet been reported in humans.

CYTOCHROME P450 2C8 (CYP2C8) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase levels of drugs metabolized by CYP2C8.  Details In vitro, licorice extract from the species G. glabra and G. uralensis inhibits CYP2C8 isoenzymes (94822). Theoretically, these species of licorice might increase levels of drugs metabolized by CYP2C8; however, this interaction has not yet been reported in humans.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase or decrease levels of drugs metabolized by CYP2C9.  Details There is conflicting evidence about the effect of licorice on CYP2C9 enzyme activity. In vitro research shows that extracts from the licorice species G. glabra and G. uralensis moderately inhibit CYP2C9 isoenzymes (10300,94822). However, evidence from an animal model shows that licorice extract from the species G. uralensis can induce hepatic CYP2C9 activity (14441). Until more is known, licorice should be used cautiously in people taking CYP2C9 substrates.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, licorice might increase or decrease levels of drugs metabolized by CYP3A4.  Details Pharmacokinetic research shows that the licorice constituent glycyrrhizin, taken in a dosage of 150 mg orally twice daily for 14 days, modestly decreases the area under the concentration-time curve of midazolam by about 20%. Midazolam is a substrate of CYP3A4, suggesting that glycyrrhizin modestly induces CYP3A4 activity (59808). Animal research also shows that licorice extract from the species G. uralensis induces CYP3A4 activity (14441). However, licorice extract from G. glabra species appear to inhibit CYP3A4-induced metabolism of testosterone in vitro. It is thought that the G. glabra inhibits CYP3A4 due to its constituent glabridin, which is a moderate CYP3A4 inhibitor in vitro and not present in other licorice species (10300,94822). Until more is known, licorice should be used cautiously in people taking CYP3A4 substrates.

DIGOXIN (Lanoxin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of licorice with digoxin might increase the risk of cardiac toxicity.  Details Overuse or misuse of licorice with cardiac glycoside therapy might increase the risk of cardiac toxicity due to potassium loss (10393).

DIURETIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of licorice with diuretic drugs might increase the risk of hypokalemia.  Details Overuse of licorice might compound diuretic-induced potassium loss (10393,20045,20046,59812). In one case report, a 72-year-old male with a past medical history of hypertension, type 2 diabetes, hyperlipidemia, arrhythmia, stroke, and hepatic dysfunction was hospitalized with severe hypokalemia and uncontrolled hypertension due to pseudohyperaldosteronism. This was thought to be provoked by concomitant daily consumption of a product containing 225 mg of glycyrrhizin, a constituent of licorice, and hydrochlorothiazide 12.5 mg for 1 month (108577).

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might increase or decrease the effects of estrogen therapy.  Details Theoretically, licorice might interfere with estrogen therapy due to estrogenic and anti-estrogenic effects (7860,16058).

LOOP DIURETICS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, loop diuretics might increase the mineralocorticoid effects of licorice.  Details Theoretically, loop diuretics might enhance the mineralocorticoid effects of licorice by inhibiting the enzyme that converts cortisol to cortisone; however, bumetanide (Bumex) does not appear to have this effect (3255).

METHOTREXATE (Trexall, others) Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, licorice might increase levels of methotrexate.  Details Animal research suggests that intravenous administration of glycyrrhizin, a licorice constituent, and high-dose methotrexate may delay methotrexate excretion and increase systemic exposure, leading to transient elevations in liver enzymes and total bilirubin (108570). This interaction has not yet been reported in humans.

MIDAZOLAM (Versed) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, licorice might decrease levels of midazolam.  Details In humans, the licorice constituent glycyrrhizin appears to moderately induce the metabolism of midazolam (59808). This is likely due to induction of cytochrome P450 3A4 by licorice. Until more is known, licorice should be used cautiously in people taking midazolam.

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might decrease the absorption of P-glycoprotein substrates.  Details In vitro research shows that licorice can increase P-glycoprotein activity (104561).

PACLITAXEL (Abraxane, Onxol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might decrease plasma levels and clinical effects of paclitaxel.  Details Multiple doses of licorice taken concomitantly with paclitaxel might reduce the effectiveness of paclitaxel. Animal research shows that licorice 3 grams/kg given orally for 14 days before intravenous administration of paclitaxel decreases the exposure to paclitaxel and increases its clearance. Theoretically, this occurs because licorice induces cytochrome P450 3A4 enzymes, which metabolize paclitaxel. Notably, a single dose of licorice did not affect exposure or clearance of paclitaxel (102959).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, licorice might decrease plasma levels and clinical effects of warfarin.  Details Licorice seems to increase metabolism and decrease levels of warfarin in animal models. This is likely due to induction of cytochrome P450 2C9 (CYP2C9) metabolism by licorice (14441). Advise patients taking warfarin to avoid taking licorice.

(Read more about LICORICE)

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, inhibits cytochrome P450 (CYP) 1A2 (94787). Theoretically, schizonepeta might increase the effects and side effects of CYP1A2 substrates.  Details Some substrates of CYP1A2 include clozapine (Clozaril), cyclobenzaprine (Flexeril), fluvoxamine (Luvox), haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), olanzapine (Zyprexa), pentazocine (Talwin), propranolol (Inderal), tacrine (Cognex), theophylline, zileuton (Zyflo), zolmitriptan (Zomig), and others.

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, inhibits cytochrome P450 (CYP) 2D6 (94787). Theoretically, schizonepeta might increase the effects and side effects of CYP2D6 substrates.  Details Some substrates of CYP2D6 include amitriptyline (Elavil), codeine, desipramine (Norpramin), flecainide (Tambocor), haloperidol (Haldol), imipramine (Tofranil), metoprolol (Lopressor, Toprol XL), ondansetron (Zofran), paroxetine (Paxil), risperidone (Risperdal), tramadol (Ultram), venlafaxine (Effexor), and others.

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, inhibits cytochrome P450 (CYP) 2E1 (94787). Theoretically, schizonepeta might increase the effects and side effects of CYP2E1 substrates.  Details Some substrates of CYP2E1 include acetaminophen, chlorzoxazone (Parafon Forte), ethanol, theophylline, and anesthetics such as enflurane (Ethrane), halothane (Fluothane), isoflurane (Forane), and methoxyflurane (Penthrane).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Animal research suggests that schizonepetin, a monoterpene constituent of schizonepeta, induces cytochrome P450 (CYP) 3A4 (94787). Theoretically, schizonepeta might decrease the effects of CYP3A4 substrates.  Details Some substrates of CYP3A4 include lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), triazolam (Halcion), and numerous others.

(Read more about SCHIZONEPETA)

ANTIBIOTIC DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, antibiotics may decrease the activity of soy isoflavones.  Details Intestinal bacteria are responsible in part for converting soy isoflavones into their active forms. Antibiotics may decrease the amount of intestinal bacteria and decrease its ability to convert isoflavones (7657).

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = A Soy can lower blood glucose and have additive effects with antidiabetes drugs.  Details Clinical research shows that whole soy diets and soy-based meals reduce fasting glucose levels in diabetic and non-diabetic individuals (75268,75296,75378,75493,96001). Also, individuals following a soy-based meal replacement plan seem to require lower doses of sulfonylureas and metformin to manage blood glucose levels when compared with individuals following a diet plan recommended by the American Diabetes Association (75268).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = A Theoretically soy protein may have additive effects with antihypertensive drugs and increase the risk of hypotension.  Details Although some contradictory research exists (14254), most clinical evidence suggests that consuming soy protein modestly reduces systolic and diastolic blood pressure in individuals with prehypertension or hypertension (13139,75482).

CAFFEINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, soy might reduce the clearance of caffeine.  Details Soy contains genistein. Taking genistein 1 gram daily for 14 days seems to inhibit caffeine clearance and metabolism in healthy females (23582). This effect has been attributed to inhibition of the cytochrome P450 1A2 (CYP1A2) enzyme, which is involved in caffeine metabolism. It is unclear if this effect occurs with the lower amounts of genistein found in soy.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Soy might modestly induce CYP2C9 enzymes. However, this effect does not seem to be clinically significant.  Details In vitro research suggests that an unhydrolyzed soy extract might induce CYP2C9. However, the significance of this interaction is likely minimal. In healthy females taking a specific extract of soy (Genistein Soy Complex, Source Naturals), blood levels of losartan, a CYP2C9 substrate, were not significantly affected (16825).

DIURETIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, soy might have additive effects when used with diuretic drugs.  Details Animal research suggests that genistein, a soy isoflavone, increases diuresis within 6 hours of subcutaneous administration in rats. The effects seem to be similar to those of furosemide (75604). This effect has not been reported in humans.

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, soy might competitively inhibit the effects of estrogen replacement therapy.  Details Soy contains phytoestrogens and has been shown to have estrogenic activity in some patients (3860). Although this has not been demonstrated in humans, theoretically, concomitant use of soy with estrogen replacement therapy might reduce the effects of the estrogen replacement therapy.

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Soy products might reduce the absorption of levothyroxine in some patients.  Details Preliminary clinical research and a case report suggest that soy-based formulas inhibit the absorption of levothyroxine in infants with congenital hypothyroidism (20636,20637,75548,90959). A levothyroxine dosage increase may be needed for infants with congenital hypothyroidism while using soy-based formulas, and the dose may need to be reduced when soy-based formulas are no longer administered. However, in postmenopausal adults, clinical research shows that taking a single dose of soy extract containing isoflavones 60 mg along with levothyroxine does not affect the oral bioavailability of levothyroxine (95996).

MONOAMINE OXIDASE INHIBITORS (MAOIs) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = C Taking soy products containing high amounts of tyramine along with MAOIs can increase the risk of hypertensive crisis.  Details Fermented soy products such as tofu and soy sauce contain tyramine, a naturally occurring chemical that affects blood pressure regulation. The metabolism of tyramine is decreased by MAOIs. Consuming more than 6 mg of tyramine while taking an MAOI can increase the risk of hypertensive crisis (15649). The amount of tyramine in fermented soy products is usually less than 0.6 mg per serving; however, there can be significant variation depending on the specific product used, storage conditions, and length of storage. Storing one brand of tofu for a week can increase tyramine content from 0.23 mg to 4.8 mg per serving (15649,15701,15702). Advise patients taking MAOIs to avoid fermented soy products that contain high amounts of tyramine.

PROGESTERONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = A Theoretically, combining soy isoflavones with transdermal progesterone may worsen bone density.  Details Clinical research suggests that significant bone loss may occur in females with osteoporosis who receive a combination of transdermal progesterone with soy milk containing isoflavones when compared with placebo, soy milk alone, or progesterone alone (69859).

TAMOXIFEN (Nolvadex) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, estrogenic soy isoflavones might alter the effects of tamoxifen.  Details Laboratory research suggests that genistein and daidzen, isoflavones from soy, can antagonize the antitumor effects of tamoxifen under some circumstances (7072,14362,8966); however, soy isoflavones might have different effects when used at different doses. A relatively low in vitro concentration of soy isoflavones such as 1 microM/L seems to interfere with tamoxifen, whereas high in vitro concentrations such as those >10 microM/L might actually enhance tamoxifen effects. People on a high-soy diet have soy isoflavones levels ranging from 0.1-6 microM/L. Until more is known, advise patients taking tamoxifen to avoid therapeutic use of soy products.

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, soy might interfere with the effects of warfarin.  Details Soy milk has been reported to decrease the international normalized ratio (INR) in a patient taking warfarin. The mechanism of this interaction is not known (9672). However, animal and in vitro research suggests that soy may also inhibit platelet aggregation (3992). Dosing adjustments for warfarin may be necessary.

(Read more about SOY)

(Read more about SOYBEAN OIL)

General ...Orally, burdock is well tolerated when consumed as a food. Although a thorough evaluation of safety outcomes is lacking, there has been long-standing historical use of burdock with few noted adverse effects.
Serious Adverse Effects (Rare):
All ROAs: Allergic reactions, including contact dermatitis and anaphylaxis.

Dermatologic ...Contact dermatitis has been reported secondary to burdock, especially after prolonged use of the root oil (37422). There are cases of allergic dermatitis secondary to using burdock plasters. Two males and a 14 year-old female developed erythematous and vesicular, pruritic, and exudative reactions in areas corresponding to the application of burdock root plasters (12667). Reactions occurred up to 7 days after initial use. Patch testing was positive for burdock sensitivity in all three patients and was nonreactive in matched controls.

Hematologic ...In one case report, a 38-year-old female developed immune-mediated thrombocytopenia after consuming a "cleansing" tea containing unknown amounts of burdock and yellow dock. The patient presented with bruising, mild weakness, and fatigue, which started 2-3 days after consuming the tea, and was found to have a platelet count of 5,000 per mcL. Symptoms resolved after platelet transfusion and treatment with oral dexamethasone (108971). It is unclear if these effects were caused by burdock, yellow dock, the combination, or other contributing factors.

Hepatic ...A case of idiosyncratic drug-induced liver disease (DILI) is reported in a 36-year-old female who presented with abdominal pain after 1 month of taking an herbal liver detox tea containing burdock and other ingredients. Remarkable laboratory values included elevated liver enzymes, alkaline phosphatase, and total bilirubin. The patient received a loading dose of N-acetylcysteine and was hospitalized for 12 days (112178). However, it is unclear if the adverse effect was due to burdock, other ingredients, or the combination.

Immunologic ...There is one case of anaphylactic shock secondary to eating boiled burdock. One hour after eating boiled burdock the patient presented with redness over the entire body and dyspnea. He was found to have low blood pressure and was treated with subcutaneous epinephrine 1 mg and intravenous lactated ringer's solution containing hydrocortisone 100 mg and dexamethasone 8 mg. The cause of anaphylactic shock was attributed to allergenicity to burdock based on positive skin prick test results. Previously, the patient had experienced urticaria after eating boiled burdock (12660).

Neurologic/CNS ...Anticholinergic reactions including dry mouth, dizziness, blurred vision, weakness, dilated pupils, inability to urinate, and bradycardia have been reported following the consumption of burdock products (12662,37421,37431,37434,37435). However, these anticholinergic reactions are believed result from contamination of burdock with belladonna alkaloids. Burdock itself does not contain atropine or other constituents that would be responsible for these reactions.

(Read more about BURDOCK)

General ...Adverse effects of forsythia have not been reported. However, a thorough evaluation of safety outcomes has not been conducted.

(Read more about FORSYTHIA)

General ...Orally, honeysuckle seems to be well tolerated. No adverse effects have been reported. There is insufficient reliable information available about the safety of honeysuckle when used topically. However, a thorough evaluation of safety outcomes has not been conducted.

Immunologic ...Topically, applying honeysuckle to the skin has been associated with contact dermatitis in a case report (12611). Orally, a case of biopsy-confirmed allergic drug eruption is reported in a young adult male after taking honeysuckle granules 30 grams over a 24-hour period. Symptoms resolved with discontinuation of honeysuckle and 2-weeks of antihistamine and glucocorticoid therapy (112866).

(Read more about HONEYSUCKLE)

General ...There is currently a limited amount of information on the adverse effects of Japanese mint. A thorough evaluation of safety outcomes has not been conducted.
Most Common Adverse Effects:
Topically: Contact dermatitis.
Serious Adverse Effects (Rare):
Inhaled: Asthma, bronchial spasm, glottal spasm, respiratory failure.

Dermatologic ...Topically, Japanese mint may cause contact dermatitis (11,18).

Pulmonary/Respiratory ...Topically, use of Japanese mint oil on the face in children can trigger glottal or bronchial spasm, asthma-like attacks, or respiratory failure (18). When inhaled, the vapor from Japanese mint oil can cause flushing, headache, or worsening bronchial asthma spasms (11,18).

(Read more about JAPANESE MINT)

General ...Orally, licorice is generally well tolerated when used in amounts commonly found in foods. It seems to be well tolerated when licorice products that do not contain glycyrrhizin (deglycyrrhizinated licorice) are used orally and appropriately for medicinal purposes or when used topically, short-term.
Most Common Adverse Effects:
Orally: Headache, nausea, and vomiting.
Topically: Contact dermatitis.
Intravenously: Diarrhea, itching, nausea, and rash.
Serious Adverse Effects (Rare):
Orally: Case reports have raised concerns about acute renal failure, cardiac arrest, cardiac arrhythmias, hypertension, hypokalemia, muscle weakness, paralysis, pseudohyperaldosteronism, and seizure associated with long-term use or large amounts of licorice containing glycyrrhizin.

Cardiovascular ...Orally, excessive licorice ingestion can lead to pseudohyperaldosteronism, which can precipitate cardiovascular complications such as hypertension and hypertensive crisis, ventricular fibrillation or tachycardia, sinus pause, and cardiac arrest. These effects are due to the licorice constituent glycyrrhizin and usually occur when 20-30 grams or more of licorice product is consumed daily for several weeks (781,15590,15592,15594,15596,15597,15599,15600,16835,97213) (104563,108574,108576,110305,112234). In one case report, an 89-year-old female taking an herbal medicine containing licorice experienced a fatal arrhythmia secondary to licorice-induced hypokalemia. The patient presented to the hospital with recurrent syncope, weakness, and fatigue for 5 days after taking an herbal medicine containing licorice for 2 months. Upon admission to the hospital, the patient developed seizures, QT prolongation, and ventricular arrhythmia requiring multiple defibrillations. Laboratory tests confirmed hypokalemia and pseudohyperaldosteronism (112234).
However, people with cardiovascular or kidney conditions may be more sensitive, so these adverse events may occur with doses as low as 5 grams of licorice product or glycyrrhizin 100 mg daily (15589,15593,15598,15600,59726). A case report in a 54-year-old male suggests that malnutrition might increase the risk of severe adverse effects with excessive licorice consumption. This patient presented to the emergency room with cardiac arrest and ventricular fibrillation after excessive daily consumption of licorice for about 3 weeks. This caused pseudohyperaldosteronism and then hypokalemia, leading to cardiovascular manifestations. In spite of resuscitative treatment, the patient progressed to kidney failure, refused dialysis, and died shortly thereafter (103791).

Dermatologic ...There have been reports of contact allergy, resulting in an itchy reddish eruption, occurring in patients that applied cosmetic products containing oil-soluble licorice extracts (59912). There have also been at least 3 cases of allergic contact dermatitis reported with the topical application of glycyrrhizin-containing products to damaged skin. In one case report, a 31-year-old female with acne presented with a 2-year history of pruritic erythematous-scaly plaques located predominantly on the face and neck after the use of a cosmetic product containing licorice root extract 1%. The patient had a positive skin patch test to licorice root extract, leading the clinicians to hypothesize that the use of benzoyl peroxide, a strong irritant, might have sensitized the patient to licorice (108578). Burning sensation, itching, redness, and scaling were reported rarely in patients applying a combination of licorice, calendula, and snail secretion filtrate to the face. The specific role of licorice is unclear (110322).
In rare cases, the glycyrrhizin constituent of licorice has caused rash and itching when administered intravenously (59712).

Endocrine ...Orally, excessive licorice ingestion can cause a syndrome of apparent mineralocorticoid excess, or pseudohyperaldosteronism, with sodium and water retention, increased urinary potassium loss, hypokalemia, and metabolic alkalosis due to its glycyrrhizin content (781,10619,15591,15592,15593,15594,15595,15596,15597,15598)(15600,16057,16835,25659,25660,25673,25719,26439,59818,59822)(59832,59864,91722,104563,108568,108574,110305,112234). These metabolic abnormalities can lead to hypertension, edema, EKG changes, fatigue, syncope, arrhythmias, cardiac arrest, headache, lethargy, muscle weakness, dropped head syndrome (DHS), rhabdomyolysis, myoglobinuria, paralysis, encephalopathy, respiratory impairment, hyperparathyroidism, and acute kidney failure (10393,10619,15589,15590,15593,15594,15596,15597,15599)(15600,16057,16835,25660,25673,25719,26439,31562,59709,59716)(59720,59740,59787,59820,59826,59882,59889,59900,91722,97214,100522) (104563,108576,108577). These effects are most likely to occur when 20-30 grams of licorice products containing glycyrrhizin 400 mg or more is consumed daily for several weeks (781,15590,15592,15594,15596,15597,15599,15600,16835,108574). However, some people may be more sensitive, especially those with hypertension, diabetes, heart problems, or kidney problems (15589,15593,15598,15600,59726,108576,108577) and even low or moderate consumption of licorice may cause hypertensive crisis or hypertension in normotensive individuals (1372,97213). The use of certain medications with licorice may also increase the risk of these adverse effects (108568,108577). One case report determined that the use of large doses of licorice in an elderly female stabilized on fludrocortisone precipitated hypokalemia and hypertension, requiring inpatient treatment (108568). Another case report describes severe hypokalemia necessitating intensive care treatment due to co-ingestion of an oral glycyrrhizin-specific product and hydrochlorothiazide for 1 month (108577). Glycyrrhetinic acid has a long half-life, a large volume of distribution, and extensive enterohepatic recirculation. Therefore, it may take 1-2 weeks before hypokalemia resolves (781,15595,15596,15597,15600). Normalization of the renin-aldosterone axis and blood pressure can take up to several months (781,15595,108568). Treatment typically includes the discontinuation of licorice, oral and intravenous potassium supplementation, and short-term use of aldosterone antagonists, such as spironolactone (108574,108577).
Chewing tobacco flavored with licorice has also been associated with toxicity. Chewing licorice-flavored tobacco, drinking licorice tea, or ingesting large amounts of black licorice flavored jelly beans or lozenges has been associated with hypertension and suppressed renin and aldosterone levels (12671,12837,97214,97215,97217,108574). One case report suggests that taking a combination product containing about 100 mg of licorice and other ingredients (Jintan, Morishita Jintan Co.) for many decades may be associated with hypoaldosteronism, even up to 5 months after discontinuation of the product (100522). In another case report, licorice ingestion led to hyperprolactinemia in a female (59901). Licorice-associated hypercalcemia has also been noted in a case report (59766).

Gastrointestinal ...Nausea and vomiting have been reported rarely following oral use of deglycyrrhizinated licorice (25694,59871). Intravenously, the glycyrrhizin constituent of licorice has rarely caused gastric discomfort, diarrhea, or nausea (59712,59915).

Immunologic ...There have been reports of contact allergy, resulting in an itchy reddish eruption, occurring in patients that applied cosmetic products containing oil-soluble licorice extracts (59912). There have also been at least 3 cases of allergic contact dermatitis reported with the topical application of glycyrrhizin-containing products to damaged skin. In one case report, a 31-year-old female with acne presented with a 2-year history of pruritic erythematous-scaly plaques located predominantly on the face and neck after the use of a cosmetic product containing licorice root extract 1%. The patient had a positive skin patch test to licorice root extract, leading the clinicians to hypothesize that the use of benzoyl peroxide, a strong irritant, might have sensitized the patient to licorice (108578).

Musculoskeletal ...In a case report, excessive glycyrrhizin-containing licorice consumption led to water retention and was thought to trigger neuropathy and carpal tunnel syndrome (59791).

Neurologic/CNS ...Orally, licorice containing larger amounts of glycyrrhizin may cause headaches. A healthy woman taking glycyrrhizin 380 mg daily for 2 weeks experienced a headache (59892). Intravenously, the glycyrrhizin constituent of licorice has rarely caused headaches or fatigue (59721). In a case report, licorice candy ingestion was associated with posterior reversible encephalopathy syndrome accompanied by a tonic-clonic seizure (97218).

Ocular/Otic ...Orally, consuming glycyrrhizin-containing licorice 114-909 grams has been associated with transient visual loss (59714).

Pulmonary/Respiratory ...Orally, large amounts of licorice might lead to pulmonary edema. In one case report, a 64-year old male consumed 1020 grams of black licorice (Hershey Twizzlers) containing glycyrrhizin 3.6 grams over 3 days, which resulted in pulmonary edema secondary to pseudohyperaldosteronism (31561). Intravenously, the glycyrrhizin constituent of licorice has caused cold or flu-like symptoms, although these events are not common (59712,59721).

(Read more about LICORICE)

General ...There is currently a limited amount of information available about the adverse effects of schizonepeta. Orally, a specific combination product (Zemaphyte, Phytopharm Plc) containing schizonepeta and numerous other ingredients has been reported to cause nausea, vomiting, colic, dyspepsia, dizziness, headache, and hair loss (12627,12630). However, it is unclear if these effects are due to schizonepeta or the other ingredients.
High doses of schizonepeta may be hepatotoxic due to its pulegone constituent (12620,12626).

Gastrointestinal ...Orally, a specific combination product (Zemaphyte, Phytopharm Plc) containing schizonepeta and numerous other ingredients has been reported to cause nausea, vomiting, colic, and dyspepsia (12627,12630). However, it is unclear if these effects are due to schizonepeta or the other ingredients.

Hepatic ...Schizonepeta contains pulegone, a hepatotoxin. When taken orally in high doses, schizonepeta may be hepatotoxic due to this constituent (12620,12626).

Neurologic/CNS ...Orally, a specific combination product (Zemaphyte, Phytopharm Plc) containing schizonepeta and numerous other ingredients has been reported to cause dizziness and headache (12627,12630). However, it is unclear if these effects are due to schizonepeta or the other ingredients.

(Read more about SCHIZONEPETA)

General ...Orally, soy is well tolerated.
Most Common Adverse Effects:
Orally: Bloating, constipation, diarrhea, and nausea.
All ROAs: Allergic reactions.

Endocrine ...In the 1950s and 1960s, cases of altered thyroid function, particularly goiter, were reported in children taking soy formula. However, adding iodine to soy formula or replacing soy flour in formula with soy protein isolate has nearly eliminated the risk of altered thyroid function in most infants (75353,75651).
In adults, there is some evidence that soy intake can alter thyroid function. Results from one clinical trial suggests that consuming soybeans 30 grams daily for as little as one month can increase thyroid-stimulating hormone (TSH) and decrease thyroxine, causing diffuse goiters, constipation, fatigue, and lethargy in some Japanese men. Recovery was achieved by discontinuing soybean intake (75206,75353). There is also some evidence that soy inhibits thyroid hormone synthesis resulting in increased secretion of TSH in some postmenopausal patients (7806). However, this seems to only occur in people with iodine deficiency (6466,75311). In postmenopausal patients with normal levels of iodine, taking a soy extract for 6 months does not seem to significantly affect thyroid hormone levels (13010).
Evidence from a single case-control study suggests that consumption of soy-based formulas may be associated with an observed three-fold increase in the risk of breast development in Puerto Rican children less than 2 years-old (75520). The correlation has been attributed to the estrogenic activity of soy. However, other risk factors, including a maternal history of ovarian cysts and consumption of meat products were also associated with the increased risk of breast development prior to 2 years of age. Also, the investigators noted that in over half of the cases, the child had not been exposed to soy or any of the other risk factors. Therefore, factors other than soy consumption may be more strongly associated with the increased risk of breast development prior to 2 years of age.

Gastrointestinal ...Gastrointestinal upset, such as constipation, diarrhea, bloating, and nausea are the most common side effects of soy (2297,11033,11082,15851,75491,95999). Reports of "bad taste" and taste intolerance have also been documented in clinical research (15851,39007,75491). Firmer stools, diarrhea, colitis, and intestinal mucosal damage has been reported in infants fed soy protein formula (75161,75448,75516,75525).

Genitourinary ...Orally, soy might increase discomfort during menstrual periods. Evidence from a small, retrospective cohort study has found that consuming soy formula as an infant may slightly increase the duration and discomfort of menstrual periods later in life. However, the investigators noted that these differences may not be clinically significant (7331).
Orally, frequent soy consumption might be a risk factor for uterine leiomyoma, an estrogen-dependent benign tumor located on the uterus. Observational research found that consumption of soy milk or soybean at least four times weekly is associated with a 7-fold increased odds of uterine leiomyoma (98869).
There is some concern that use of soy-based formulas in infants might result in long-term health complications. However, results from a retrospective cohort study has found that intake of soy-based formula as an infant does not affect height, weight, body mass index, pubertal maturation, menstrual history, or pregnancy history, nor does it increase the risk of reproductive organ disorders, hormonal disorders, libido dysfunction, or birth defects in the offspring of adults who received soy formula as infants (7331,11080). Additionally, research in adults shows that urinary phytoestrogens are not associated with endometriosis risk (101804). However, some population research has found that regular exposure to soy-based formulas during infancy is associated with an increased risk for endometriosis (101803).

Immunologic ...Orally, soy can cause allergic reactions such as skin rash and itching in some people (6412). In an 11-year-old female, allergy to soy protein resulting in a delayed itching papular rash was thought to be responsible for the reaction to injected benzathine benzylpenicillin containing possible soy protein-contaminated soy lecithin (96422).
Topically, soy-based ingredients were responsible for the development of hand atopic dermatitis in a young female using cosmetic lotions in the workplace. Percutaneous sensitization resulted in the development of anaphylaxis to oral soy (96000).

Neurologic/CNS ...Orally, one clinical study showed that insomnia was more common in postmenopausal adults taking soy isoflavone supplements when compared with those receiving placebo (9917). Some research suggests that dietary consumption of tofu during midlife might decrease cognitive function in later years. Evidence from one retrospective cohort study suggests that males who consume at least two servings of tofu weekly during midlife have increased risk of cognitive impairment in late life (19% vs. 4%) compared to those who consume tofu less frequently. Although the effect of tofu was considered to be marginal compared to other factors such as age, education, or history of stroke, results from the study suggest that the effect of significant midlife consumption of tofu is comparable to the effect of an age difference of 4 years or an education difference of 3 years. However, numerous other factors, such as lifestyle and health, could be involved (6415,6416). Therefore, these findings are too preliminary to be used as a basis for clinical recommendations.

Oncologic ...There is controversy about the role of soy in breast cancer. Population studies suggest that soy is protective against breast cancer. Asian females who eat a traditional diet high in soy seem to have a lower risk of developing breast cancer (4590,5939,9674). Early exploratory studies have suggested that soy stimulates proliferation of normal human breast tissue (3980,3981). However, taking a soy tablet containing 50 mg soy isoflavones daily for 12 months does not alter mammographic or breast MRI tissue density in adults at high risk of breast cancer, with non-endocrine treated breast cancer, or previously treated for breast cancer and without evidence of recurrence (95999).
There is some concern that soy supplements, but not soy foods, might increase the risk of endometrial hyperplasia due to its estrogenic effects. Population and clinical research suggests that soy foods do not have a proliferative effect on endometrial cells (7358,2429,7654,9676,9917), and increased dietary soy and phytoestrogens are associated with reduced endometrial cancer risk (7338,10372). However, the effects seem to be different with concentrated soy isoflavone extract. While taking products providing isoflavones 120 mg daily for 6 months does not increase endometrial thickening (13209), taking higher doses such as isoflavones 150 mg daily for 5 years might increase the risk of simple endometrial hyperplasia (12105). However, there is no evidence that soy isoflavones increase the risk of atypical hyperplasia which has a much higher risk of developing into endometrial cancer than simple endometrial hyperplasia (12105,90973).
There is also concern that increased soy intake increases the risk for other types of cancer. Some observational research has found that higher dietary intake of soy is associated with a higher risk for bladder cancer and pancreatic cancer (9677,105609).
A meta-analysis of results from cohort and case-control studies evaluating the risk of stomach cancer related to consumption of fermented soy products is unclear and inconclusive. The highest quality data from cohort studies suggests that these products have no significant effect on stomach cancer (7340,7341). More research is required to determine if soy products have any correlation with stomach cancer.

Pulmonary/Respiratory ...Inhaled soy dust and soy hull aeroallergen can trigger symptoms of asthma and allergic rhinitis (5084,5085,5086).

(Read more about SOY)

General ...Orally, soybean oil seems to be generally well tolerated. No adverse effects have been reported in clinical trials in adults eating foods enriched with soybean oil or taking supplements containing soybean oil unsaponifiable fractions (10693,10694,33238,33257,93110,93111). Soybean oil can cause an allergic reaction in sensitive individuals (4079,4080,93683).

Immunologic ...Soybean oil can cause an allergic reaction in individuals allergic to the Fabaceae/Leguminosea family. Members of this family include peanuts, soybeans, and others (4079,4080). The inclusion of soybean oil as an inactive ingredient in a generic formulation of the drug omeprazole caused anaphylaxis in two females with soybean allergies (93683).

(Read more about SOYBEAN OIL)