Gamma Oryzanol


Gamma Oryzanol Introduction

Gamma oryzanol, an ester of ferulic acid, is a natural antioxidant that is primarily found in grain products. Produced from rice bran oil, Gamma oryzanol has been traditionally used by the Japanese as a medicinal agent in the treatment of menopause, gastrointestinal problems, and elevated cholesterol/triglyceride levels. Due to its potent antioxidant effects, gamma oryzanol may also be effective at inhibiting certain cancers, as well as limiting the damaging effects of radiation exposure and chemotherapy. [1, 2]

Research suggests that gamma oryzanol acts on the hypothalamus and pituitary glands, inhibiting the output of certain hypothalamic and pituitary hormones. Hormones affected include; growth hormone, thyroid-stimulating hormone (TSH), prolactin, and leutinizing hormone. However, studies remain mixed on gamma oryzanol’s mechanism of action; with some studies actually reporting an increase in the secretion percentages of the aformentioned hormone. More studies are needed to fully determine the overall effects of gamma oryzanol on hypothalamic and pituitary hormones. [1, 2]

Gamma Oryzanol Food Sources

The best dietary sources include the bran portion of grains such as rice, wheat, barley, and oats. Other food sources include vegetables (esp. asparagus, tomatoes, and peas), citrus fruits, berries, and olives. [1]

Gamma Oryzanol Uses

Gamma oryzanol may be useful for the treatment of high serum cholesterol and triglyceride levels. [1, 6] One study found that treatment with gamma oryzanol reduced cholesterol levels in mildly hypercholesterolemic men in a 4-week period. [3] Several studies suggest that gamma oryzanol’s cholesterol-lowering effects may be due to its ability to increase conversion of cholesterol to bile acid, increase excretion of bile acid, and reduce absorption of cholesterol. [1, 7, 8]

Gamma oryzanol may have anticancerous properties, Several preliminary animal studies have shown that gamma oryzanol may help inhibit tumor cell growth. [9, 10] One study suggests that gamma oryzanol may protect against the damaging effects of radiation exposure and chemotherapy.[11] More human studies are needed to determine gamma oryzanol’s anticancer effects.

Gamma oryzanol may be useful for treatment of menopausal symptoms. Several studies found that treatment with gamma oryzanol improved symptoms in menopausal women.[1, 2, 12, 13] Gamma oryzanol’s beneficial effects appear to be due to its ability to reduce secretion of leutinizing hormone (LH) by the pituitary and increase excretion of endorphins by the hypothalamus. [1]

Gamma oryzanol may be useful for athletes and body builders to increase lean body mass and strength, improve recovery after workouts, and help repair the muscle damage that can result from intense exercise. [1, 14] A particular double-blind study reports that bodybuilders who took 30 milligrams daily of gamma oryzanol increased body weight and strength over a period of 8-weeks. [1, 14] However, other study results do not support these claims. [15, 16] Opposing studies have shown that supplementation with gamma oryzanol during resistance exercise training had no effect on strength or performance. [15] This application for gamma oryzanol remains debatable. Certainly, more research is needed to provide evidence that gamma oryzanol has a positive effect on exercise performance.

Gamma oryzanol may be useful for various digestive disorders such as stomach ulcers, gastritis, and irritable bowel syndrome. [1, 17, 18] Gamma oryzanol’s beneficial effects appear to be due to its ability to reduce the secretion of gastric acid and normalize the nervous system control of digestive secretions.

Gamma Oryzanol Dosages

Dosage: 300 - 500 milligrams daily for therapeutic applications.

Delivery Forms: Tablets, capsules, and liquid. [1, 2]

Gamma Oryzanol Deficiencies and Toxicities

Gamma Oryzanol Deficiencies

Deficiency signs and symptoms have not been reported in medical literature. [1]

Gamma Oryzanol Toxicities

Pregnant, lactating women, and children should not take supplemental gamma oryzanol, unless recommended by a health care provider. [1, 2]

Gamma oryzanol is considered a safe, natural substance. No side effects have been reported with its use. No interactions with gamma-oryzanol and any drug or nutrient have been reported.

Always inform your health care provider about the dietary supplements you are taking, since there may be a potential for side effects, interactions, or allergy.


1. Murray MT. Encyclopedia of Nutritional Supplements, NY: Three Rivers Press, 1996: 332-335.

2. Gamma Oryzanol, Dietary Supplement Information Bureau:

3. Berger A, Rein D, Schafer A, et al. Similar cholesterol-lowering properties of rice bran oil, with varied gamma-oryzanol, in mildly hypercholesterolemic men. Eur J Nutr. May2004;:1-11.

4. Scavariello EM, Arellano DB. Gamma-oryzanol: an important component in rice bran oil. Arch Latinoam Nutr. Mar1998;48(1):7-12.

5. Nakayama S, Manabe A, Suzuki J, et al. Comparative effects of two forms of gamma-oryzanol in different sterol compositions on hyperlipidemia induced by cholesterol diet in rats. Jpn J Pharmacol. Jun1987;44(2):135-43.

6. Sasaki J et al. Effects of gamma-oryzanol on serum lipids and apolipoproteins in dyslipidemic schizophrenics receiving major tranquilizers. Clin Ther 1990;12:263-268.

7. Sakamoto K, Tabata T, Shirasaki K. Effects of gamma-oryzanol and cycloartenol ferulic acid ester on cholesterol diet induced hyperlipidemia in rats. Jpn J Pharmacol. Dec1987;45(4):559-65.

8. Seetharamaiah GS, Chandrasekhara N. Effect of oryzanol on cholesterol absorption & biliary & fecal bile acids in rats. Indian J Med Res. Dec1990;92:471-5.

9. Tanaka T et al. Inhibition of 4-nitroquinoline-1-oxide-induced rat tongue carcinogenisis by the naturally occurring plant phenolics caffeic, ellagic, chlorogenic and ferulic acids. Carcinogenesis 1993; 14:1321-1325.

10. Asanoma M et al. Inhibitory effect of topical application of polymerized ferulic acid, a synthetic lignin, on tumor promotion in mouse skin two stage tumorigenesis. Carcinogenesis 1994; 15:2069-2071.

11. Graf E. Antioxidant potential of ferulic acid. Free Rad Biol Med 1992; 13:435-448.

12. Ishihara M. Effect of of gamma-oryzanol on serum lipid peroxide levels and climacteric disturbances. Asia Oceania J Ostet Gynecol 1984; 10:317

13. Ishihara M, Ito Y, Nakakita T, et al. Clinical effect of gamma-oryzanol on climacteric disturbance -on serum lipid peroxides. Nippon Sanka Fujinka Gakkai Zasshi. Feb1982;34(2):243-51.

14. Bucci LR, et al. Effect of ferulate on strength and body composition of weightlifters. J Appl Sport Sci Res. 1990;4:104-109.

15. Fry AC, Bonner E, Lewis DL, et al. The effects of gamma-oryzanol supplementation during resistance exercise training. Int J Sport Nutr. Dec1997;7(4):318-29.

16. Wheeler KB, Garleb KA. Gamma oryzanol-plant sterol supplementation: metabolic, endocrine, and physiologic effects. Int J Sport Nutr. Jun1991;1(2):170-7.

17. Ichimaru Y, Moriyama M, Ichimaru M, Gomita Y. Effects of gamma-oryzanol on gastric lesions and small intestinal propulsive activity in mice. Nippon Yakurigaku Zasshi. Dec1984;84(6):537-42.

18. Mizuta K, Itaya K. Effects of gamma-oryzanol on gastric secretions in rats. Nippon Yakurigaku Zasshi. Mar1978;74(2):285-95.


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