Hyaluronic Acid by FoodScience of Vermont

POSSIBLY INEFFECTIVE

• Hyperlipidemia. A meta-analysis of small clinical studies suggests that consuming chia seeds, flour, powder, or oil for 7-24 weeks does not improve lipid levels in patients with conditions associated with hyperlipidemia. Details: A meta-analysis of 10 small clinical trials in patients with various metabolic conditions, including diabetes, metabolic syndrome, nonalcoholic fatty liver disease, and obesity, shows that consuming chia seeds, flour, or powder 15-60 grams daily for 7-24 weeks, or taking chia oil 6 grams daily for 8 weeks, does not reduce total cholesterol, low-density lipoprotein (LDL) cholesterol, or triglyceride levels or increase high-density lipoprotein (HDL) cholesterol levels when compared with control groups consuming wheat bran, oat bran, dietary fiber, poppy seeds, or soybean oil (106657). While the patient populations in the studies analyzed are more likely to develop hyperlipidemia, it is unclear if these findings can be generalized to patients diagnosed with hyperlipidemia.
• Obesity. Small clinical studies suggest that consuming chia seeds for up to 12 weeks does not reduce body weight in overweight or obese adults. Details: One small clinical study in overweight or obese individuals shows that ingesting chia seeds 25 grams mixed in 0.25 liters of water twice daily before meals for 12 weeks does not improve body composition or reduce blood pressure when compared with placebo (25533). Another small clinical study in overweight, postmenopausal females shows that ingesting milled or whole chia seeds 25 grams daily for 10 weeks does not improve body composition or blood pressure when compared to baseline (25532).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Athletic performance. It is unclear if oral chia is beneficial for improving athletic performance. Details: A small clinical study in trained athletes shows that drinking a beverage containing 50% of calories from chia seeds (Greens Plus Omega 3 Chia seeds) and 50% of calories from a carbohydrate-containing beverage (Gatorade) for 2 days prior to participating in an endurance exercise lasting more than 90 minutes leads to similar performance when compared with Gatorade alone (25531).
• Cardiovascular disease (CVD). Although there has been interest in using oral chia for CVD, there is insufficient reliable information about the clinical effects of chia for this purpose.
• Diabetes. Small clinical studies suggest that consuming chia for 4-6 months might reduce systolic blood pressure (SBP) in patients with type 2 diabetes, although it does not appear to improve glycemic control or lipid levels and has shown mixed effects on body weight and inflammatory markers. Details: One small clinical trial in patients with type 2 diabetes shows that consuming bread containing a specific, selectively bred type of chia (Salba, Salba Smart Natural Products LLC), providing 37 grams of chia daily for 12 weeks reduces SBP, C-reactive protein, and vonWillebrand factor, but not lipid levels, when compared with consuming bread containing wheat bran. This form of chia also significantly reduced glycated hemoglobin (HbA1c) when compared to baseline, but not when compared with a wheat bran control (16124). Another small clinical study in adults with type 2 diabetes and obesity shows that consuming Salba chia 40 grams daily, either baked into bread or as a powder, in conjunction with a restricted calorie diet for 6 months reduces weight by 1.6 kg and waist circumference by 2.8 cm when compared with an oat bran control. However, consuming chia had no effect on body fat percentage, HbA1c, or fasting glucose levels (97940). Also, a small clinical study in adults with type 2 diabetes shows that consuming chia seeds 40 grams daily for 12 weeks reduces SBP, but does not improve body weight, HbA1c, or levels of fasting glucose, lipids, or C-reactive protein, when compared with those not consuming chia (106658).
• Hypertension. It is unclear if oral chia is beneficial in patients with hypertension. Details: A very small clinical study in patients with mild hypertension shows that consuming chia flour 35 grams daily for 12 weeks reduces systolic blood pressure (SBP) by around 10 mm Hg and diastolic blood pressure (DBP) by almost 9 mm Hg when compared to baseline. In patients already taking antihypertensive drugs, chia seems to have an even greater impact on SBP and DBP. However, in patients not being treated with antihypertensive drugs, chia flour modestly reduces SBP by 6.5%, but does not significantly reduce DBP. No improvements in blood pressure were reported in patients consuming a wheat bran control (91516).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral chia is beneficial in patients with NAFLD. Details: Small, uncontrolled clinical studies in patients with NAFLD show that consuming milled chia seeds 25 grams daily for 8 weeks may reduce hepatic steatosis, as measured by the liver: spleen attenuation ratio, in up to 43% of subjects with prediabetes and 100% of subjects with diabetes when compared to baseline. Chia seed supplementation may also modestly reduce visceral fat, body mass index, and waist circumference in patients with prediabetes when compared to baseline, but does not seem to improve lipid levels (104530,110438). The validity of these findings is limited by the lack of a comparator group in both studies.
• Metabolic syndrome. Oral chia has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with metabolic syndrome shows that reducing daily caloric intake by 500 kcal and drinking a beverage containing chia seed 4 grams, soy protein 32 grams, dehydrated nopal 7 grams, and oat 22 grams daily for 2 months reduces body weight, body mass index, and waist circumference when compared to baseline, but not when compared with following a reduced calorie diet alone. However, following the reduced calorie diet and drinking this beverage appears to lower serum triglycerides and C-reactive protein and improve glucose tolerance when compared with a reduced calorie diet alone (25534). It is unclear if these findings are due to chia, other ingredients, or the combination.
• Muscle strength. It is unclear if oral chia is beneficial for increasing muscle strength and muscle mass during resistance training. Details: A very small clinical trial in healthy, non-resistance trained males shows that drinking a supplemental beverage containing chia flour 50 grams, providing 20 grams of protein and 3 grams of omega-3 fatty acids, is no more effective than whey protein 20 grams or placebo for augmenting the increases in muscle strength and fat-free mass that occur with an 8-week whole body resistance training program (112385). The habitual baseline diet of the study participants already contained dietary protein intakes recommended for strength training, and the beverage was only consumed three times per week immediately after training sessions.
• Pruritus. It is unclear if topical chia seed oil is beneficial in patients with pruritus. Details: One very small, uncontrolled clinical study in patients with xerotic pruritus or pruritus caused by kidney failure or diabetes shows that applying lotion containing chia seed oil 4% for 8 weeks improves skin hydration and reduces the severity of lichen simplex chronicus and prurigo nodularis when compared to baseline (25537). The validity of these findings is limited by the small study size and lack of a comparator group. More evidence is needed to rate chia for these uses.

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POSSIBLY EFFECTIVE

• Dry eye. Applying eye drops containing hyaluronic acid alone or in combination with other ingredients, seems to improve symptoms of dry eye. Details: A large meta-analysis of clinical studies in patients with dry eye disease shows that using eye drops containing hyaluronic acid 0.1% to 0.4% for at least 14 days modestly improves tear production when compared with artificial tears or saline control, with a more significant improvement when compared with saline control. Tear stability is also modestly improved when compared with saline control (108622). Several individual clinical studies using specific hyaluronic acid eye drops have also demonstrated improvement. One clinical study in patients with dry eye disease shows that applying eye drops containing hyaluronic acid 0.1% to 0.3% 5-6 times daily for 12 weeks might improve symptoms to a similar degree as cyclosporine 0.05% eye drops. The products used in this study included Hyalein ophthalmic solution 0.1%, New Hyaluni ophthalmic solution 0.15%, and Hyaluni ophthalmic solution 0.3% (97885). Another clinical study shows similar efficacy between hyaluronic acid 0.15% eye drops (New Hyaluni), applied 6 times daily for 12 weeks, and eye drops containing cyclosporine 0.05% and carboxymethylcellulose 0.5%, applied twice daily (110555). A smaller clinical study in patients with dry eye disease shows that applying specific eye drops containing hyaluronic acid 0.2% (Hyalistil) seems to have similar efficacy as using tamarind seed polysaccharide eye drops (16301). Furthermore, adding hyaluronic acid to conventional treatment seems to offer additional benefit. A large multicenter clinical trial in patients with dry eye disease shows that applying 1-2 drops of artificial tears containing carboxymethylcellulose 0.5% and hyaluronic acid 0.1% (Optive Fusion, Allergan) at least 2 times daily for 3 months seems to further improve pain and discomfort when compared with using artificial tears containing carboxymethylcellulose alone (104384). One small clinical study also shows that hyaluronic acid 0.3% ocular gel and hyaluronic acid 0.18% eye drops, applied 4-6 times daily for 12 weeks, are equally effective for improving dry eye symptoms (110556). Hyaluronic acid has also been studied in combination with other ingredients. Several small clinical studies in patients with dry eye syndrome ranging from mild to severe shows that applying eye drops containing hyaluronic acid 0.2% or 0.3%, polyvinylpyrrolidone, and glycerin (Visaid 0.2% or 0.3%, Avizor S.A.), administered as one drop 3-8 times daily for one month, improves some signs and symptoms of dry eye when compared with sodium chloride 0.9% (97894,97895). Conversely, a large clinical study in patients with mild to moderate dry eye disease shows that applying preservative-free eye drops containing sodium hyaluronate with chondroitin sulfate (Humylub Ofteno PF, Laboratorios Sophia), one drop into each eye four times daily for 90 days, seems to be no different for improving dry eye severity when compared with using polyethylene/propylene glycol eye drops (104443).
• Venous leg ulcers. Topical application of hyaluronic acid-impregnated gauze reduces wound size and promotes wound healing. Details: Clinical studies in patients with at least one leg ulcer of venous or mixed arterial/venous origin show that once daily application of a specific hyaluronic acid-impregnated gauze (Ialuset, Laboratoires Genévrier) reduces wound size at 45 days by 73% and produces complete wound healing at or before 20 weeks in 40% of patients. In those receiving a neutral vehicle gauze, these improvements occurred in 46% and 19% of patients, respectively (108627,108640).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging skin. Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. It is also unclear if topical hyaluronic acid is beneficial for aging skin. Details: A very small study shows that taking a specific combination product (GliSODin Skin Nutrients Advanced Anti-Aging Formula, Isocell North America Inc.) containing hyaluronic acid, krill oil, sea buckthorn berry oil, and cacao bean extract orally three times daily for 90 days, along with applying tazarotene 0.1% cream, moderately decreases wrinkling and photodamage and improves skin moisture and elasticity when compared with tazarotene cream alone (91778). Another small clinical study in females with aging skin shows that taking a specific combination product (BioCell Collagen, BioCell Technology, LLC) containing hyaluronic acid 100 mg, chondroitin sulfate 200 mg, and collagen peptides 600 mg daily for 12 weeks reduces lines and wrinkles by about 13% when compared with baseline (28681). The validity of this finding is limited by the lack of a comparator group. Furthermore, it should be noted that both studies were funded by the product manufacturer. A small open-label clinical study in females with mild to moderate lip dryness and mild to severe lip condition shows that three daily applications of a two-step lip treatment containing hyaluronic acid for 4 weeks improves the overall condition of lips, as well as texture/visual roughness, plumpness, color/rosiness, definition/contour, and lines/wrinkles when compared with baseline (108634). The validity of these findings is limited by the lack of a comparator group.
• Allergic rhinitis (hay fever). It is unclear if nasal irrigation with sodium hyaluronate is beneficial in patients with mild, persistent seasonal allergic rhinitis. Details: A small clinical study in patients with mild, persistent seasonal allergic rhinitis receiving an oral antihistamine and an intranasal corticosteroid shows that nasal irrigation with sodium hyaluronate twice daily for 1 month improves mucociliary clearance time by 3 minutes, compared with 1 minute with the use of isotonic saline and 5 minutes with the use of surfactant (108630). It is unclear if this change is associated with clinically relevant symptom improvement.
• Burns. It is unclear if topical hyaluronic acid is beneficial in patients with burns. Details: A meta-analysis of small clinical trials suggests that topical hyaluronic acid and hyaluronic acid derivatives might improve the healing of wounds, including burns, when compared with control (104389). A small nonrandomized clinical study in patients with partial- to full-thickness burns shows that hyaluronic acid 0.2% gel daily for 12 weeks during the re-epithelialization phase reduces erythema, tension, pruritus, burning, and neoangiogenesis when compared with baseline (108636). The lack of statistical comparison to the ozonated oil group and the single-blinded nature of the study limit the validity of these findings.
• Canker sores. It is unclear if topical hyaluronic acid is beneficial for canker sores. Details: A clinical study in adults with recurrent canker sores shows that applying a gel containing hyaluronic acid 0.2% two to three times daily for 7 days reduces soreness immediately and for up to 30 minutes after application when compared with baseline. However, these improvements are numerically similar to those seen with placebo (108637). The lack of statistical comparison to placebo limits the validity of this finding. A small observational study in children with recurrent canker sores has found that applying a gel containing hyaluronic acid 0.2% twice daily for 7 days is similarly effective to dexamethasone topical ointment applied three times daily for 5 days for reducing pain and ulcer size (104388).
• Corneal abrasion. It is unclear if eye drops containing hyaluronic acid are beneficial in preventing recurrence in patients with a history of traumatic corneal abrasion. Details: A small clinical study in patients with fully healed traumatic corneal abrasion at risk for recurrence shows that administration of eye drops containing hyaluronic acid 0.3% five times daily for 3 months does not reduce the incidence rate of major symptomatic episodes at 12 months when compared with observation alone (108623).
• Diabetic foot ulcers. Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of results from 4 clinical studies shows that applying hyaluronic acid combination gels or hyaluronic acid-based biomaterials to diabetic foot ulcers increases the odds of complete healing at 12 weeks by about 1.7-fold when compared to control treatment. Forms of hyaluronic acid assessed in the evaluated studies included zinc hyaluronate, hyaluronic acid-based biomaterial (Hyalograft 3D autograft), and a gel containing hyaluronic acid and amino acids (Vulnamin Gel, Errekappa) (91776). It is not clear if the beneficial effects were due to hyaluronic acid or other components of the treatments.
• Exercise-induced muscle soreness. Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in healthy, recreationally active adults shows that a specific product (BioCell Collagen, BioCell Technology, LLC) containing hyaluronic acid 150 mg, chondroitin sulfate 300 mg, and collagen peptides 900 mg, taken twice daily for 6 weeks prior to two bouts of resistance exercise, attenuates muscle damage and decreases delayed-onset muscle soreness when compared with placebo (96301). It is unclear if these effects are due to hyaluronic acid, the other ingredients, or the combination. Furthermore, it should be noted that both studies were funded by the product manufacturer.
• Gastroesophageal reflux disease (GERD). Oral hyaluronic acid has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Patients with non-erosive GERD are thought to be less responsive to conventional acid suppression with proton pump inhibiters (PPIs) and H-2 blockers. A small preliminary clinical study shows that taking a syrup containing hyaluronic acid and chondroitin sulfate along with PPIs, H2-receptor antagonists, and/or antacids, reduces the intensity of symptoms associated with non-erosive GERD by about 3.5-fold when compared with placebo (89592). A larger clinical study in patients with non-erosive GERD shows that taking a different formulation of the same combination of chondroitin sulfate and hyaluronic acid (Esoxx, Alfa Wassermann) 4 times daily for 14 days, in conjunction with a PPI, improves GERD symptom severity by 21%, heartburn by 15%, and regurgitation by 10% when compared with using a PPI and placebo (101271). Hyaluronic acid has also been evaluated in combination with chondroitin sulfate in patients with extraesophageal symptoms of GERD. A small, open-label study shows that taking a specific combination product (Gerdoff, SOFAR S.p.A.) containing hyaluronic acid and chondroitin sulfate three times daily with omeprazole 40 mg daily for 6 weeks increases the rate of treatment response, defined as a 50% or greater improvement in reflux symptoms index scores, by around 40% when compared with omeprazole alone. While average symptom scores were not significantly improved with the combination product over omeprazole, the need for omeprazole as rescue therapy for breakthrough symptoms was reduced in the treatment group (109648). It is unclear if the findings described above are due to hyaluronic acid, chondroitin sulfate, or the combination.
• Gingivitis. It is unclear if hyaluronic acid used in a mouthwash reduces gingivitis severity. Details: A small clinical study in patients with biofilm-induced gingivitis shows that rinsing with 10 mL of hyaluronic acid 0.025% mouth wash (Gengigel, RICERFARMA SRL) for 1 minute twice daily reduces probing index and bleeding when compared with rinsing with a placebo solution, but is less effective when compared with chlorhexidine 0.12% solution (104383). Another small clinical study in patients with plaque-induced gingivitis shows that rinsing with 10 mL of a mouthwash containing hyaluronic acid 0.1% and hydrogen peroxide 1.8% for 30 seconds twice daily for 21 days reduces gingival index scores but not plaque index scores when compared with placebo (110554). It is unclear if these findings are due to hyaluronic acid, hydrogen peroxide, or the combination.
• Intranasal surgery. It is unclear if topical hyaluronic acid irrigation improves recovery in patients after nasal surgery. Details: A small clinical study in patients that underwent nasal surgery for chronic rhinosinusitis shows that performing nasal irrigation with high molecular weight sodium hyaluronate 9 mg twice daily for 6 weeks improves sinus scarring, crusting, and headache when compared with nasal irrigation with saline. However, the sodium hyaluronate irrigation did not improve sinus inflammation or secretions, nasal obstruction, or facial pain (101288).
• Intrauterine adhesions. Several small studies suggest that intrauterine administration of hyaluronic acid gel seems to prevent intrauterine adhesions after uterine surgery. Details: Meta-analyses of 11-12 small clinical studies in patients undergoing uterine surgery shows that intrauterine application of 1-10 mL of hyaluronic acid gel after surgery reduces the risk of intrauterine adhesions by around 50% and increases pregnancy rates when compared with no treatment (110551,110552). One analysis suggests that hyaluronic acid is most effective for prevention of intrauterine adhesions when at least 5 mL of gel is applied (110551).
• Lichen planus. It is unclear if topical hyaluronic acid is beneficial in patients with oral lichen planus. Details: A clinical study in patients with oral lichen planus shows that application of a gel containing hyaluronic acid 0.2% four to five times daily for 28 days reduces soreness in as little as 5 minutes for up to 4 hours when compared with baseline. These findings are numerically similar to those seen with placebo; however, the lack of statistical comparison to placebo limits the validity of this finding (108635). A small clinical study in patients with symptomatic oral lichen planus (including mixed forms) shows that application of a gel containing hyaluronic acid 0.2% three times daily for 4 weeks is similarly effective to triamcinolone for improving pain, erythema, and lesion size (108633). It is unclear if the improvement from baseline differed between groups.
• Melasma. It is unclear if topical hyaluronic acid is beneficial in patients with moderate to severe facial melasma. Details: A small clinical study in patients with mostly mixed-type, moderate to severe facial melasma shows that twice daily application of hyaluronic acid along with isobutylamido thiazolyl resorcinol reduces melasma severity similarly to isobutylamido thiazolyl resorcinol alone (108628). The single-blinded nature of the study limits the validity of these findings.
• Oral mucositis. Topical hyaluronic acid has only been evaluated in combination with other ingredients; its effects when used alone is unclear. Details: A small clinical study in children aged 5 years or older with chemotherapy-induced oral mucositis shows that using a solution containing sodium hyaluronate, verbascoside, and polyvinylpyrrolidone (Mucosyte; Biopharm) three times daily is more effective than placebo for improving pain and other symptoms (97890). Another small clinical study in adults in recovery from hematopoietic stem cell transplantation shows that using a spray product containing sodium hyaluronate with synthetic amino acid precursors of collagen (Mucosamin) attenuates the development of severe oral mucositis when compared with chlorhexidine 0.2% (97889).
• Osteoarthritis. It is unclear if oral hyaluronic acid is beneficial in patients with osteoarthritis of the knee. Details: A small study in patients with knee osteoarthritis shows that taking chicken comb extract (Hyal-Joint, Bioibérica) 80 mg, standardized to contain hyaluronic acid 60% to 70%, once daily for 8 weeks does not reduce pain when compared with placebo (55742). This study was limited by small size and a significant placebo effect. Another small study in patients with knee osteoarthritis shows that taking a different supplement (Oralvisc, Bioibérica) 80 mg standardized to contain hyaluronic acid 70% and glycosaminoglycans once daily for 3 months modestly reduces pain when compared with placebo (91779). Reasons for these differing findings may relate to hyaluronic acid formulation, study funding sources, or the magnitude of placebo effect. Hyaluronic acid has also been studied in combination with chondroitin and collagen peptides (BioCell Collagen, BioCell Technology, LLC) with some evidence of benefit (28680).
• Otitis media. It is unclear if using intranasal hyaluronic acid solution is beneficial for otitis media in children. Details: Preliminary clinical research in children 3-12 years of age who have recurrent or chronic middle ear inflammation and adenoiditis shows that using a compound (Yabro, IBSA Farmaceutici Italia S.r.l.) containing hyaluronic acid in saline intranasally 15 days per month for 3 months modestly reduces the number of patients with impaired otoscopy or middle ear function when compared to baseline (97888). It is unclear if this effect is due to the hyaluronic acid product or to the natural resolution of inflammation over time.
• Radiation dermatitis. It is unclear if topical hyaluronic acid is beneficial for the prevention of radiation dermatitis. Details: A small clinical study in patients with breast cancer undergoing adjuvant radiation therapy following lumpectomy shows that three daily applications of a specific hyaluronic acid gel (RadiaPlex, MPM Medical) to one side of the breast results in a grade 2 or greater dermatitis occurrence rate of 62%, compared with a rate of 48% on the side receiving petrolatum-based gel. A review of a planned interim analysis led to early trial discontinuation (108638).
• Rhinosinusitis. It is unclear if hyaluronic acid solution is beneficial for acute or chronic rhinosinusitis when used in an intranasal saline rinse. Details: A small clinical study in adults with acute rhinosinusitis who are being treated with levofloxacin and prednisone shows that using a 3% hyaluronic acid in saline nasal douche twice daily improves smell, obstruction, and discharge within 14 days when compared with saline alone (97886). A very small clinical study in patients with chronic rhinosinusitis without nasal polyps shows that receiving micronized nasal hyaluronic acid douches twice daily for 30 days improves nasal symptoms, nasal obstruction, and ability to smell to a similar degree as normal saline (104387).
• Sexual dysfunction. It is unclear if vaginal hyaluronic acid is beneficial for improving sexual function in adults with dyspareunia. Details: A small nonrandomized clinical study in females with dyspareunia while taking oral hormonal contraceptives shows that once daily vaginal application of a hyaluronic acid gel for 12 weeks reduces pain and improves sexual function at 12 weeks when compared baseline. Though patients treated with twice weekly vaginal estrogen therapy had better 12-week scores than patients treated with hyaluronic acid, it is unclear if the improvements from baseline differed between groups (108639).
• Tooth extraction. It is unclear if topical hyaluronic acid is beneficial for wound healing after tooth extraction. Details: A small clinical study in patients undergoing tooth extraction shows that application of hyaluronic acid 0.2% gel or hyaluronic acid 0.1% spray to the extraction socket twice daily for 7 days increases the rate of wound closure when compared with no treatment (110553). The validity of these findings is limited by a lack of placebo control group.
• Urinary tract infections (UTIs). Oral and intravesical hyaluronic acid have been evaluated for the prevention of UTI in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of prospective and retrospective studies shows that intravesical administration of 50 mL of specific solutions containing chondroitin sulfate 2% and hyaluronic acid 1.6% (iAluRil, IBSA Farmaceutici; Cystistat, Bioniche), once weekly to once monthly for up to 6 months, reduces the rate of UTI recurrence by about 2-3 incidents per year and delays the time to the first UTI recurrence when compared with placebo or prophylaxis with sulfamethoxazole-trimethoprim (99688). However, the validity of these findings is limited by the low quality and high heterogeneity of the included studies, as well as concerns for publication bias. Also, the effect of hyaluronic acid alone is unclear. Oral hyaluronic acid has also been evaluated in combination with other ingredients for the prevention of recurrent UTI. A small prospective observational study shows that taking 1-2 capsules of a combination of hyaluronic acid, chondroitin sulfate, curcumin, and quercetin daily for 15 days each month, in conjunction with the use of local topical estrogen therapy for up to 12 months, reduces the number of women with recurrent UTIs when compared with taking the oral combination product or the vaginal estrogen product alone (96781). It is unclear if this effect is due to hyaluronic acid, other ingredients, or the combination.
• Vaginal atrophy. It is unclear if topical hyaluronic acid is beneficial for improving symptoms of vaginal atrophy. Details: A small, open-label clinical trial in patients going through menopause with symptoms of vaginal atrophy shows that applying 3 grams of a topical vaginal preparation of hyaluronic acid (Hyalo Gyn, Fidia Farmaceutici) every 3 days for 30 days improves vaginal health scores and reduces vaginal itching, vaginal burning, and pain during intercourse when compared to baseline. However, it does not appear to be any more effective than a polycarbophil vaginal gel (110549). Also, a small observational study in postmenopausal patients with vulvovaginal atrophy has found that applying a topical vaginal preparation containing hyaluronic acid (Justgin, JustPharma) three times weekly for 8 weeks is associated with improved symptoms of vaginal dryness, burning, and itching, as well as pain during intercourse, when compared to baseline (97887). The validity of these findings is limited by the lack of a comparator group and retrospective nature of the study. Some research has evaluated combination products containing hyaluronic acid for vaginal atrophy. A clinical trial in patients with cervical cancer shows that intravaginal administration of a specific suppository (Santes, Lo.Li. Pharma) containing hyaluronic acid, vitamin E, and vitamin A, once daily for the 5 week duration of radiotherapy reduces vaginal dryness, inflammation, and dyspareunia when compared with no additional treatment (101283). Also, a small, open-label clinical study in patients with vaginal atrophy after treatment for breast cancer shows that intravaginal application of a suppository containing hyaluronic acid and extract of aloe, marigold, tiger grass, and tea tree daily for 10 days then every 3 days for 80 days improves vaginal health scores and reduces vaginal dryness and pain during intercourse when compared to baseline, with no difference between the hyaluronic acid-containing suppository and vaginal laser therapy (110550). It is unclear if these findings are due to hyaluronic acid, other ingredients, or the combination.
• Wound healing. Small clinical studies show that topical hyaluronic acid and hyaluronic acid derivatives may improve the healing of various types of wounds. Details: A meta-analysis of small clinical trials suggest that topical hyaluronic acid and hyaluronic acid derivatives might improve the healing of burns, wounds, and skin ulcers when compared with control (104389). More evidence is needed to rate hyaluronic acid for these uses.

(Read more about HYALURONIC ACID)

LIKELY INEFFECTIVE

• Alzheimer disease. Lecithin does not improve daily functioning in patients with Alzheimer disease. Details: In patients with Alzheimer disease, taking various types of lecithin, 1.2-45 grams daily for up to 6 months, alone or in combination with various conventional medications, does not improve cognitive function or other measures of disease progression (5149,5151,5152,5156,14817,14823,14825,14837,14838).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related cognitive decline. It is unclear if oral lecithin can slow age-related cognitive decline. Details: A small clinical crossover study in healthy adults aged 64 years and older shows that taking lecithin 26 grams orally daily, alone or in combination with physostigmine, for 5 weeks does not seem to improve memory when compared with placebo (19204).
• Anxiety. Although there is interest in using oral lecithin for anxiety, there is insufficient reliable information about the clinical effects of lecithin for this condition.
• Atopic dermatitis (eczema). Although there is interest in using oral lecithin for atopic dermatitis, there is insufficient reliable information about the clinical effects of lecithin for this condition.
• Bipolar disorder. It is unclear if oral lecithin is beneficial in patients with bipolar disorder. Details: A clinical study in six patients with mania shows that taking lecithin 10 mg three times daily improves symptoms of delusions, incoherent speech, and hallucinations when compared with placebo (14839).
• Dry skin. Although there is interest in using topical lecithin for dry skin, there is insufficient reliable information about the clinical effects of lecithin for this condition.
• Friedreich ataxia. Small clinical studies suggest that oral lecithin is not beneficial in people with Friedreich ataxia. Details: Preliminary clinical research shows that taking lecithin 25 grams orally daily for 1 month does not have any benefit in people with Friedreich ataxia (59298). Other preliminary clinical research shows that taking lecithin for a longer period of 6 months also does not improve performance (19211).
• Hyperlipidemia. Although lecithin may lower cholesterol in healthy people, it does not seem to improve cholesterol levels in people with hyperlipidemia. Details: Some clinical research shows that taking lecithin 20-30 grams daily for up to 11 months decreases cholesterol in healthy people (5147,14820). However, other clinical research shows that lecithin has no effect on low-density lipoprotein cholesterol or total cholesterol levels in people with hyperlipidemia (5148,14820).
• Parkinson disease. It is unclear if oral lecithin is beneficial in patients with Parkinson disease. Details: Preliminary clinical research in patients with Parkinson disease shows that taking lecithin 32 grams daily for 8 weeks does not improve symptoms when compared with placebo (19212).
• Postoperative pain. It is unclear if oral lecithin is beneficial for reducing postoperative pain. Details: Preliminary clinical research shows that taking lecithin 20 grams prior to surgery increases choline levels, but does not reduce postoperative pain after gynecological surgery, when compared with placebo (91231).
• Tardive dyskinesia. It is unclear if oral lecithin is beneficial in patients with tardive dyskinesia. Details: Two small clinical studies in patients with tardive dyskinesia shows that taking lecithin orally for 2 months, alone or in combination with lithium, does not improve symptoms when compared with placebo (14822,14824).
• TPN-associated hepatic steatosis. It is unclear if oral lecithin is beneficial in patients with hepatic steatosis associated with long-term total parenteral nutrition (TPN). Details: A small clinical study in patients on long-term TPN with low choline levels suggests that taking lecithin 20 grams orally twice daily for 6 weeks reduces the degree of hepatic steatosis, compared with no significant changes in those taking placebo (5140).
• Ulcerative colitis. Oral lecithin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a disease-specific medical food (Profermin, Nordisk Rebalance) containing lecithin, fermented oats, barley malt, and lactobacillus plantarum, as 250 mL twice daily for 24 weeks, decreases disease activity by over 56% when compared with baseline and leads to remission in 46% of patients with mild-to-moderate ulcerative colitis (91228). Other preliminary clinical research in this population shows that taking Profermin 250 mL twice daily for 8 weeks improves disease activity and remission rate when compared with another medical food (Fresubin Original, Fresenius Kabi) (90271). The effects of lecithin alone are unclear. More evidence is needed to rate lecithin for these uses.

(Read more about LECITHIN)

LIKELY SAFE ...when used orally in amounts commonly found in foods (104531,104532).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts, short-term. Chia has been used safely at doses up to 40 grams daily for up to 6 months (16124,97940). ...when used topically, short-term. A product containing chia seed oil 4% has been applied to the skin safely for up to 8 weeks (25537).

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

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LIKELY SAFE ...when used orally and appropriately. Supplements standardized to contain hyaluronic acid 70%, in an 80 mg daily dose, have been used daily for up to 3 months with no reports of adverse effects (55742,91779). ...when used topically and appropriately. Hyaluronic acid, in a gel or impregnated gauze, has been safely applied to the skin in clinical trials (7889,7892,104389,108627,108640). ...when eye drop preparations containing up to 0.3% hyaluronic acid are used multiple times per day for up to 3 months (97885,97894,97895,110555).

PREGNANCY:
There is insufficient reliable information available about the safety of hyaluronic acid; avoid using.

LACTATION:
There is insufficient reliable information available about the safety of hyaluronic acid. It is not known if hyaluronic acid is excreted in breast milk (7890); avoid using.

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LIKELY SAFE ...when used orally in amounts commonly found in foods. Lecithin has Generally Recognized As Safe (GRAS) status in the US (2619,105544). ...when used orally and appropriately in medicinal amounts. Lecithin has been used safely in doses of up to 30 grams daily for up to 6 weeks (5140,5149,5152,5156,14817,14822,14838,19212). ...when used topically (4914).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in food amounts. Lecithin has Generally Recognized As Safe (GRAS) status in the US (105544). There is insufficient reliable information available about the safety of medicinal amounts of lecithin during pregnancy or lactation; avoid using.

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General ...Orally and topically, chia seems to be well tolerated.
Most Common Adverse Effects:
Orally: Flatulence and soft stools.
Serious Adverse Effects (Rare):
Orally: Anaphylaxis in sensitive individuals.

Cardiovascular ...Chia contains a high concentration of alpha-linolenic acid (ALA). There is some concern that ALA might increase triglyceride levels more than other omega-3 fatty acids (12918); however, clinical research with a specific variety of chia called Salba shows that it does not significantly increase triglyceride levels (16124).

Gastrointestinal ...Orally, chia might cause mild gastrointestinal adverse effects. Some patients consuming chia 40 grams daily for up to 6 months reported mild and transient gastrointestinal adverse effects such as flatulence and soft stools; however, the frequency of these adverse effects was similar to patients consuming an oat bran control (97940). Bloating and flatulence have been reported with a chia flour-based sports beverage (112385).

Immunologic ...Orally, chia might cause anaphylaxis in sensitive individuals. A single case of IgE-mediated anaphylactic reaction has been reported for a patient who consumed chia seeds. Symptoms, including pruritus in the mouth, urticaria, facial angioedema, shortness of breath, and dizziness, developed a few days after consuming chia seeds. The reaction was attributed to sensitivity to proteins in chia seeds (91517).

Oncologic ...Chia seeds contain a high concentration of alpha-linolenic acid (ALA). Epidemiologic research suggests that high dietary intake of ALA might increase risk for prostate cancer (1337,2558,7823,7147,12978). Other research suggests high intake or serum levels of ALA does not increase the overall risk of prostate cancer (12961,15736); however, it might increase the risk of advanced prostate cancer (12961). Association with prostate cancer appears to depend on the sources of ALA. Dairy and meat sources have been positively associated with prostate cancer, whereas plant sources, such as chia seed, don't seem to affect prostate cancer risk (12909). According to a clinical trial, intake of ALA does not appear to increase levels of prostate specific antigen (PSA) (91402).

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General ...Orally and topically, hyaluronic acid appears to be well tolerated.
Most Common Adverse Effects:
Topically: Eczema, erythema, itching, wound hemorrhage, wound infection (e.g., erysipelas).

Dermatologic ...The use of needle-free devices to inject hyaluronic acid for cosmetic purposes has been reported to cause serious injury, and in some cases permanent harm, to the skin, lips, and eyes (108613).
Topically, hyaluronic acid application has been reported to cause eczema, erythema, itching, wound hemorrhage, and wound infection (e.g., erysipelas) (108628,108640).

Ocular/Otic ...Ocular pain has been reported rarely in patients using eye drops containing up to 0. 3% hyaluronic acid (97885).

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General ...Orally, lecithin is well tolerated.
Most Common Adverse Effects:
Orally: Abdominal pain, diarrhea, fullness, and nausea.

Dermatologic ...Orally, lecithin can cause allergic skin reactions in people with egg or soy allergies (15705).

Gastrointestinal ...Orally, lecithin may cause abdominal pain, diarrhea, fullness, and nausea (5140,6243,14817,14822,14838,19204,59281).

Neurologic/CNS ...Orally, lecithin caused CNS complaints and agitation in one patient in a clinical trial (59261).

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