Rice Bran Oil Lowers Cholesterol

Two small studies, published in the American Journal of Clinical Nutrition (2005, vol 81, issue 1), found that rice bran oil, not fiber, significantly lowered total cholesterol and LDL cholesterol by 7 percent.

In study 1, researchers at Louisiana State University, in Baton Rouge, LA, administered a low fiber control diet (13-22 grams of dietary fiber) to 26 volunteers for 3 weeks, and then 13 of the volunteers were administered a high fiber intervention diet of defatted rice bran (56-94 grams of dietary fiber) for 5 additional weeks.

In study 2, 14 volunteers were administered a diet with rice bran oil (1/3 of the total dietary fat) substituted for an oil blend (peanut oil, olive oil, corn oil, canola oil, palm oil, and butter) that had a fatty acid composition similar to that of the rice bran oil, for 10 weeks.

The scientists measured serum lipids and factor VII in both studies.

At the end of the two studies, researchers found that the rice bran oil, not the fiber, lowered cholesterol in men and women with moderately high cholesterol. There were no changes in HDL cholesterol or factor VII. "There were no substantial differences in the fatty acid composition of the diets; therefore, the reduction of cholesterol was due to other components present in the rice bran oil, such as unsaponifiable compounds," the study authors write.

The researchers identified the most notable compound as -oryzanol, a ferulate ester of triterpene alcohols, as well as phytosterols, tocopherols, and tocotrienols. "Rice bran oil that contains these compounds could become an important functional food with cardiovascular health benefits," the researchers conclude.