Gamma Oryzanol

Overview

Gamma oryzanol is a mixture of ferulic acid esters of sterol and triterpene alcohols, which occur in rice bran oil at levels of approximately 1 to 2%. (1) These compounds function as natural antioxidant in the plants where they occur. When these substances are extracted from rice bran, they can be offered in substantially higher doses than can be obtained from dietary sources. Studies conducted primarily in Japan report that gamma oryzanol supplementation is beneficial in the treatment of menopausal symptoms, elevated cholesterol, and numerous gastrointestinal conditions. (2)

Many body builders believe the steroid nature of gamma oryzanol ingredients produces anabolic activity such as increased release of growth hormone and increased production and release of testosterone. These effects, if true, would certainly help to build muscle and improve lean body mass. However, not enough research has been conducted in this area, and some research actually refutes these claims. The same authors report that injections of gamma oryzanol in laboratory rats suppress the release of luteinizing hormone, lower the synthesis and release of growth hormone, and increase the release of dopamine and norepinephrine, in the brain. (3) Since these effects have not been studied in humans, conclusions should not be drawn.

Dosage Info

Dosage Range

30 to 300 mg daily.

Most Common Dosage

100 mg, 3 times daily.

Dosage Forms

Tablets, capsules, and liquid.

Adult RDI

None established

Adult ODA

None established

Active Forms

Gamma oryzanol, also known as ferulic acid esters

Absorption

The components in gamma oryzanol are reportedly rather poorly absorbed from the intestinal tract. (4)

Toxicities & Precautions

General

Gamma oryzanol appears to be a very safe natural product. No significant side effects have been reported in animal trials or with human usage.

Functions in the Body

Antioxidant

In a model of cholesterol oxidation, several components of gamma oryzanol including cycloartenyl ferulate, 24-methylenecycloartanyl ferulate, and campesteryl ferulate were found to have antioxidant activity 10 times greater than the major tocopherol and tocotrienol components of vitamin E. (5)

Anti-inflammatory activity

Animal studies report that gamma oryzanol provides mild anti-inflammatory activity. (6) , (7)

Lowers cholesterol

Gamma oryzanol apparently influences the metabolism and excretion of cholesterol by inhibiting cholesterol absorption, increasing both the conversion of cholesterol to bile acids, and the excretion of bile acids. (8) , (9) , (10)

Clinical Applications

Elevated Cholesterol

Studies in animals and humans indicate that gamma oryzanol helps lower elevated cholesterol levels. (11) , (12) This benefit is apparently due to a combination of effects which includes inhibition of cholesterol absorption, increased conversion of cholesterol to bile acids, and increased excretion of bile acids. (13) , (14)

Ulcers

Research in Japan indicates that gamma oryzanol has anti-ulcer activity and it may also be helpful for other types of gastrointestinal problems. (15) These effects may be due to gamma oryzanol’s ability to decrease gastric acid secretion. (16)

Increasing Lean Body Mass

Many feel that gamma oryzanol provides anabolic activity, which facilitates increasing lean muscle mass. Consequently, body builders are the largest group of people using gamma oryzanol in the United States. In one double-blind study, participants who took 30 mg/day of gamma oryzanol for 8 weeks exhibited increases in body weight and strength. (17) However, in another study, weight-trained males who ingested 500 mg/day of gamma oryzanol for 9 weeks did no better than controls in measurements of strength and performance. (18) Therefore, more research is needed before accurate conclusions can be made.

Menopause

Studies conducted in Japan suggest that gamma oryzanol may be useful in the treatment of menopause. In one study, 13 women who had undergone a hysterectomy, which is the equivalent of a surgical menopause, were instructed to take 100 mg of gamma oryzanol three times daily. Over half of the women reported a 50% reduction in menopausal symptoms such as hot flashes. (19) In another study, 40 women with climacteric disturbances were administered 300 mg of gamma oryzanol daily for 4 to 8 weeks. Two different methods of scoring were employed, and improvement in symptoms categorized as "generally recovered" was reported by 80 to 85% of the women. (20)

Symptoms and Causes of Deficiency

No deficiency condition related to gamma oryzanol has been reported or observed.

Dietary Sources

The constituents in gamma oryzanol occur naturally in rice bran.

References

  1. View Abstract: Scavariello EM, Arellano DB. Gamma-oryzanol: an important component in rice bran oil. Arch Latinoam Nutr. Mar1998;48(1):7-12.
  2. View Abstract: 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.
  3. View Abstract: Wheeler KB, Garleb KA. Gamma oryzanol-plant sterol supplementation: metabolic, endocrine, and physiologic effects. Int J Sport Nutr. Jun1991;1(2):170-7.
  4. View Abstract: Wheeler KB, Garleb KA. Gamma oryzanol-plant sterol supplementation: metabolic, endocrine, and physiologic effects. Int J Sport Nutr. Jun1991;1(2):170-7.
  5. View Abstract: Xu Z, Hua N, Godber JS. Antioxidant Activity of Tocopherols, Tocotrienols, and gamma-Oryzanol Components from Rice Bran against Cholesterol Oxidation Accelerated by 2,2'-Azobis(2-methylpropionamidine) Dihydrochloride. J Agric Food Chem. Apr2001;49(4):2077-81.
  6. Chawla AS, Singh M, Murthy MS, et al. Anti-inflammatory action of ferulic acid and its esters in carrageenan induced rat paw oedema model. Indian J Exp Biol. Mar1987;25(3):187-9.
  7. View Abstract: Akihisa T, Yasukawa K, Yamaura M, et al. Triterpene alcohol and sterol ferulates from rice bran and their anti-inflammatory effects. J Agric Food Chem. Jun2000;48(6):2313-9.
  8. View Abstract: 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. View Abstract: 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.
  10. View Abstract: 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.
  11. View Abstract: Scavariello EM, Arellano DB. Gamma-oryzanol: an important component in rice bran oil. Arch Latinoam Nutr. Mar1998;48(1):7-12.
  12. View Abstract: 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.
  13. View Abstract: Seetharamaiah GS, Chandrasekhara N. Effect of oryzanol on cholesterol absorption & biliary & fecal bile acids in rats. Indian J Med Res. Dec1990;92:471-5.
  14. View Abstract: 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.
  15. View Abstract: 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.
  16. View Abstract: Mizuta K, Itaya K. Effects of gamma-oryzanol on gastric secretions in rats. Nippon Yakurigaku Zasshi. Mar1978;74(2):285-95.
  17. Bucci LR, et al. Effect of ferulate on strength and body composition of weightlifters. J Appl Sci Res. 1990;4:104-109.
  18. View Abstract: 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.
  19. Murase Y, Iishima H. Clinical studies of oral administration of gamma-oryzanol on climacteric complaints and its syndrome. Obstet Gynecol Prac. 1963;12:147-9.
  20. View Abstract: 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.