Recent research shows that a specific component of rice bran has heart-healthy effects. It is the oil, and not the fibre, that helps to lower cholesterol. Rice bran oil is a good example of functional food with a beneficial effect - lowering cholesterol to reduce risk for cardiovascular disease. Previous research has also pointed to the heart-healthy effects of rice bran and rice bran oil, which is most commonly available in Japan and India. Researchers from the Pennington Biomedical Research Center in Baton Rouge, Louisiana, found that adding rice bran to the diet of men and women with moderately high cholesterol lowered cholesterol levels just as effectively as an oat bran-containing diet. In another study by the same researchers, they found that middle age and elderly study participants who substituted rice bran oil for their usual cooking oils experienced decrease in their cholesterol levels. In the first study, 26 men and women were randomly assigned to a low-fibre diet, in which they consumed up to 22 grams of fibre per day, or a high-fibre diet with defatted rice bran, in which they consumed twice as much fibre as the other group. The defatted rice bran was used in cookies and breads. At the end of the five-week study, none of the patients experienced great changes in their overall blood cholesterol levels. An unexpected finding was that subjects in the defatted rice bran group had higher levels of low-density lipoprotein (LDL) cholesterol - the artery-clogging "bad" cholesterol. In the second study, 14 participants followed two different diets for five weeks each. During the first five-week period the study participants consumed one third of their total daily dietary fat in the form of a blend of peanut oil, olive oil, corn oil, canola oil, palm oil and butter. During the second five-week period, the oil blend was replaced with rice bran oil. The oil blend had a fatty acid composition similar to that found in rice bran oil. Rice bran is high in saturated fatty acids, which has been shown to have deleterious effects on cholesterol levels. Thus, a diet consisting of rice bran oil would not be expected to lower cholesterol. At the end of the study, however, the researchers found that the study participants' cholesterol levels - LDL cholesterol in particular - were lowest when their diet consisted of rice bran oil. The findings from both studies show that it is the rice bran oil, and not the fibre, that lowers blood lipids in men and women with borderline high total cholesterol.
American Journal of Nutrition,
January 2005