Oregano Oil [Discontinued] by Allergy Research Group

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there has been interest in using topical oregano oil for acne, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Asthma. Although there has been interest in using oral oregano for asthma, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Bronchitis. Although there has been interest in using oral oregano for bronchitis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Canker sores. Although there has been interest in using topical oregano oil for canker sores, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Cough. Although there has been interest in using oral oregano for cough, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Dandruff. Although there has been interest in using topical oregano oil for dandruff, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Diabetes. Although there has been interest in using oral oregano for diabetes, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Dysmenorrhea. Although there has been interest in using oral oregano for dysmenorrhea, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Dyspepsia. Although there has been interest in using oral oregano for dyspepsia, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Gingivitis. Although there has been interest in using topical oregano oil for gingivitis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Headache. Although there has been interest in using topical oregano oil for headache, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Insect repellent. Although there has been interest in using topical oregano oil as an insect repellent, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Intestinal parasite infection. It is unclear if oral oregano is beneficial in patients with intestinal parasite infections. Details: In one small, uncontrolled study, taking a specific emulsified oregano leaf oil product (ADP, Biotics Research Corporation) 200 mg orally three times daily with meals for 6 weeks resulted in eradication of Blastocystis hominis, Entamoeba hartmanni, and Endolimax nana from the stool in 10 of 13 patients (6878). The clinical significance of this is unclear since the Centers for Disease Control (CDC) considers Entamoeba hartmanni and Endolimax nana to be non-pathogenic, while blastocystosis caused by Blastocystis hominis is usually self-limiting and does not require treatment.
• Pain (acute). Although there has been interest in using topical oregano oil for the relief of acute pain, including joint and muscle pain, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Psoriasis. Although there has been interest in using topical oregano oil for psoriasis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Rhinosinusitis. Although there has been interest in using oral oregano for rhinosinusitis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Seborrheic dermatitis. Although there has been interest in using topical oregano oil for seborrheic dermatitis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Tinea capitis. Although there has been interest in using topical oregano oil for tinea capitis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Tinea corporis. Although there has been interest in using topical oregano oil for tinea corporis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Tinea pedis. Although there has been interest in using topical oregano oil for tinea pedis, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Toothache. Although there has been interest in using topical oregano oil for toothache, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Upper respiratory tract infection (URTI). Although there has been interest in using oral oregano for URTIs, such as the common cold and influenza, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Urinary tract infections (UTIs). Although there has been interest in using oral oregano for UTIs, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Varicose veins. Although there has been interest in using topical oregano oil for varicose veins, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Warts. Although there has been interest in using topical oregano oil for warts, there is insufficient reliable information about the clinical effects of oregano for this purpose.
• Wound healing. It is unclear if topical oregano is beneficial for improving healing or preventing infections in people with skin wounds. Details: One small clinical trial shows that applying an ointment containing a 3% concentration of the water-soluble fraction of the oregano plant twice daily for 10-14 days after minor dermatological surgery might reduce infection rates and improve scar formation when compared with petrolatum ointment (67348). More evidence is needed to rate oregano for these uses.

(Read more about OREGANO)

POSSIBLY EFFECTIVE

• Dyslipidemia. Taking full-fat rice bran, reduced-fat rice bran, or rice bran oil daily appears to modestly reduce lipoprotein (LDL) cholesterol levels. The effects of rice bran on other types of cholesterol are unclear. Details: Clinical research in adults with hypercholesterolemia shows that taking full-fat rice bran 85 grams daily for 6 weeks lowers total cholesterol by 8% and LDL cholesterol by 14% when compared with placebo. Rice bran does not seem to affect triglycerides or high-density lipoprotein (HDL) cholesterol (865). Conversely, a meta-analysis of 8 small clinical studies in patients with hypercholesterolemia, type 2 diabetes, or who have survived colorectal cancer shows that taking rice bran 20 to 100 grams/day does not improve total cholesterol, LDL, HDL, or triglycerides when compared with control (112092). However, the interpretation of these findings is limited by the heterogeneity of patients, dosages, and study designs included in the analysis. The oil from rice bran has also been shown to affect the lipid profile (1354,97524,100481,106591). Multiple meta-analyses of small clinical studies show that taking rice bran oil for 2.5-13 weeks reduces LDL cholesterol levels by 7-8 mg/dL when compared with control. However, rice bran oil does not appear to affect HDL cholesterol levels. Rice bran oil may also modestly lower triglyceride levels; however, results are conflicting between meta-analyses (97524,106591). The validity of these findings is limited by inclusion of low-quality studies and the inclusion of patients without hypercholesterolemia at baseline. The effectiveness of rice bran oil may also depend on the content of gamma-oryzanol. A small clinical study in patients with hyperlipidemia shows that taking rice brain oil 30 mL containing 4000, 8000, and 11000 ppm gamma-oryzanol daily for 4 weeks decreases LDL-C levels when compared with control. The greatest effects occurred in the patients receiving higher gamma-oryzanol content (8000 and 11000 ppm) (100481).

POSSIBLY INEFFECTIVE

• Colorectal cancer. Clinical and population research suggest that consuming dietary cereal fiber, including rice bran, doesn't seem to reduce the risk of colorectal cancer. Details: Clinical research in adults with colorectal adenomas shows that increasing dietary fiber, including rice bran, for up to 4 years does not reduce the risk of recurrent adenomas (4820). Observational research in females has also found that increasing dietary fiber consumption, including rice bran, for up to 16 years is not associated with colorectal cancer risk (4821). However, the validity of these studies is limited by the use of multiple sources of dietary fiber.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alcohol use disorder. Although there has been interest in using oral rice bran for alcohol use disorder, there is insufficient reliable information about the clinical effects of rice bran for this purpose.
• Alopecia areata. Although there has been interest in using topical rice bran for alopecia areata, there is insufficient reliable information about the clinical effects of rice bran for this purpose.
• Androgenic alopecia. It is unclear if topical rice bran is beneficial in patients with androgenic alopecia. Details: One small clinical study shows that applying dermal rice bran 5% supercritical CO2 extract (RB-SCE) 4 mL to the scalp twice daily for 16 weeks improves hair density and visual ratings of hair growth in males, but not females, with androgenic alopecia when compared with placebo (97523).
• Athletic performance. Although there has been interest in using oral rice bran for athletic performance, there is insufficient reliable information about the clinical effects of rice bran for this purpose.
• Atopic dermatitis (eczema). It is unclear if topical rice bran is beneficial in patients with atopic dermatitis. Details: Low-quality observational research has found that using a topical rice bran broth bath for 2-5 months reduces skin symptoms in approximately 69% to 94% of patients with atopic dermatitis when compared with baseline. However, the validity of this study is limited by the lack of a comparator group (872).
• Cardiovascular disease (CVD). There is limited evidence on the oral use of rice bran oil in coronary artery disease (CAD). Details: Preliminary clinical research in adult males who recently underwent angioplasty for CAD shows that taking oral rice bran oil 30 grams daily for 8 weeks improves left ventricular ejection fraction by 35% more when compared with taking sunflower oil 30 grams daily. Taking rice bran oil also improves triglyceride and low-density lipoprotein cholesterol levels, but not high-density lipoprotein cholesterol levels, when compared with placebo (106590).
• Diabetes. It is unclear if oral rice bran is beneficial in patients with type 2 diabetes. Details: A small clinical study in adults with type 2 diabetes shows that ingesting stabilized rice bran 20 grams once daily for 12 weeks does not reduce fasting blood glucose, postprandial glucose, or glycated hemoglobin (HbA1c) when compared with ingesting a placebo of 20 grams milled rice flour (97522). However, this study may not have been adequately powered to identify a difference between groups.
• Gastric cancer. Although there has been interest in using oral rice bran to prevent gastric cancer, there is insufficient reliable information about the clinical effects of rice bran for this purpose.
• Halitosis. It is unclear if oral rice bran is beneficial in patients with halitosis. Details: Preliminary clinical research shows that swishing with 15 mL of rice bran oil for 10 minutes and spitting it out, also referred to as "oil pulling", once daily for 14 days, improves halitosis scores when compared with baseline in pregnant adults with halitosis. Rice bran oil was similarly effective to sesame oil or chlorhexidine for reducing halitosis (97526).
• HIV/AIDS. Although there has been interest in using oral rice bran for HIV/AIDS, there is insufficient reliable information about the clinical effects of rice bran for this purpose.
• Hypercalciuria. It is unclear if oral rice bran is beneficial in patients with hypercalciuria. Details: Preliminary observational research in adults with idiopathic hypercalciuria shows that taking oral defatted rice bran 10 grams twice daily for up to 3 years reduces annual kidney stone recurrence by 83% when compared with baseline (876). The validity of this study is limited by the lack of a comparator group.
• Hypertension. Although there has been interest in using oral rice bran for hypertension, there is insufficient reliable information about the clinical effects of rice bran for this purpose.
• Insomnia. It is unclear if oral rice bran is beneficial in patients with insomnia. Details: A small clinical study in patients with disturbed sleep shows that taking a specific rice bran extract (S&D Co.) 1000 mg daily for 2 weeks improves total sleep time by about 20 minutes when compared with placebo. Taking rice bran extract also modestly improves sleep efficiency and sleep quality scores when compared with placebo (103760).
• Obesity. Although there has been interest in using oral rice bran for obesity, there is insufficient reliable information about the clinical effects of rice bran for this purpose. More evidence is needed to rate rice bran for these uses.

(Read more about RICE BRAN)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Oregano leaf and oil have Generally Recognized as Safe (GRAS) status in the US (4912). There is insufficient reliable information available about the safety of oregano when used orally in amounts greater than those found in food. There is also insufficient reliable information available about the safety of oregano when used topically. Oregano oil in concentrations of greater than 1% may be irritating when applied to mucous membranes (67348,88188).

PREGNANCY: POSSIBLY UNSAFE
when used orally in medicinal amounts. Oregano is thought to have abortifacient and emmenagogue effects (19,7122,19104).

LACTATION:
There is insufficient reliable information available about the safety of oregano when used in medicinal amounts; avoid amounts greater than those found in food.

(Read more about OREGANO)

LIKELY SAFE ...when used orally and appropriately. Rice bran and rice bran oil in doses of up to 30 grams daily have been used safely in studies lasting up to 5 years. Higher doses, up to 85 grams daily, have been used safely for 6 weeks in clinical trials (865,876,877,880,1354,106588,106590). There is insufficient reliable information available about the safety of topical rice bran.

CHILDREN: POSSIBLY SAFE
when used orally and appropriately in infants. Rice bran 1-5 grams daily for up to 6 months has been consumed with apparent safety by infants 6-12 months of age (103761).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in amounts commonly found in foods. There is insufficient reliable information available about the safety of rice bran when used for medicinal purposes during pregnancy and lactation; avoid using.

(Read more about RICE BRAN)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, oregano might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.  Details In vitro research shows that aristolochic acid isolated from oregano leaves has antithrombin activity (67164). It has also been reported that oregano oil inhibits arachidonic acid-induced, and ADP-induced, platelet aggregation (49445).

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, oregano might increase the risk for hypoglycemia when taken with antidiabetes drugs.  Details In vitro and animal research shows that oregano extracts might lower blood glucose levels (67191,67204,110122).

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General ...Orally, oregano is well tolerated when used in amounts typically found in foods. There is currently a limited amount of information available about the safety of oregano when used in larger amounts as medicine.
Most Common Adverse Effects:
Orally: Gastrointestinal upset.
Topically: Dermatitis in sensitive individuals.
Serious Adverse Effects (Rare):
Orally: Systemic allergic reactions, including anaphylaxis, in sensitive individuals.

Dermatologic ...Oregano has been reported to cause allergic contact dermatitis (46902). Topically, oregano oil in concentrations of greater than 1% has been reported to cause irritation when applied to mucous membranes (67348,88188).

Gastrointestinal ...Orally, large amounts of oregano can cause gastrointestinal upset. Concentrated, non-emulsified oil of oregano can cause localized irritation of the gastrointestinal tract (6878).

Immunologic ...Systemic allergic reactions have been reported with oregano. A 45-year-old male developed pruritus, respiratory difficulty, hypotension, swelling of the lips and tongue, and facial edema after ingesting pizza seasoned with oregano. He had 2 similar episodes after ingesting foods seasoned with thyme, another member of the Lamiaceae family. He did not react to similar foods without the seasoning, and he had positive skin tests to plants of the Lamiaceae family (3705).

(Read more about OREGANO)

General ...Orally, rice bran is generally well tolerated. However, increasing the amount of bran in the diet can cause transient abdominal discomfort, flatulence, and erratic bowel habits.
Most Common Adverse Effects:
Orally: Abdominal discomfort, erratic bowel habits, flatulence.
Topically: Erythema, itching.
Serious Adverse Effects (Rare):
All ROAs: Anaphylactic reactions, including urticaria and angioedema.

Dermatologic ...Topically, rice bran broth baths can cause itching and skin redness (872). In rare cases, rash and itching from rice bran has been associated with contact infestation with Pyemotes tritici, an arthropod commonly called straw itch mite (2284).

Gastrointestinal ...Orally, increasing the amount of bran in the diet can cause erratic bowel habits, flatulence, and abdominal discomfort during the first few weeks (272,106588).

Immunologic ...Orally and topically, rice bran can cause allergic reactions such as urticaria, angioedema, wheezing, itching, and cough (100733,106589). In a case report, a 5-year-old male presented with allergic eczema, urticaria, and cough due to rice bran ingestion (100733). In another case report, a 14-year-old male developed food-dependent, exercise-induced anaphylaxis after consuming 150 grams of rice bran. The 52-kDa and 63-kDa globulin constituents in rice bran have both been implicated as the source of allergic reactions (100732,106589). These constituents are not typically present in cooked, polished rice (106589).

Other ...Be aware that rice bran is a source of inorganic arsenic, which is known to negatively impact long-term health. The amount of inorganic arsenic in rice bran is unknown. However, a small analysis of powder and tablet rice bran products shows that, to exceed the provisional tolerable weekly intake of inorganic arsenic, a person weighing 65 kg would need to consume over 295 grams of rice bran tablets daily or 109 grams of rice bran powder daily. These amounts are higher than the recommended amount of rice bran tablet (3 grams daily) and rice bran powder (10-20 grams daily) listed on the labels of most available supplements (100500).

(Read more about RICE BRAN)