RICE BRAN OIL CONSUMPTION AND PLASMA-LIPID LEVELS IN MODERATELY HYPERCHOLESTEROLEMIC HUMANS

The effect of rice bran oil, an oil not commonly consumed in the Unite d States, on plasma lipid and apolipoprotein concentrations was studie d within the context of a National Cholesterol Education Panel (NCEP) Step 2 diet and compared with the effects of canola, com, and olive oi ls. The study subjects were 15 middle-aged and elderly subjects (8 pos tmenopausal women and 7 men; age range, 44 to 78 years) with elevated low-density lipoprotein (LDL) cholesterol (C) concentrations (range, 1 33 to 219 mg/dL). Diets enriched in each of the test oils were consume d by each subject for 32-day periods in a double-blind fashion and wer e ordered in a Latin square design. All food and drink were provided b y the metabolic research unit. Diet components were identical (17% of calories as protein, 53% as carbohydrate, 30% as fat [<7% as saturated fat], and 80 mg cholesterol/1000 kcal) except that two thirds of the fat in each diet was contributed by rice bran, canola, com, or olive o il. Mean+/-SD plasma total cholesterol concentrations were 192+/-19, 1 94+/-20, 194+/-19, and 205+/-19 mg/dL, and LDL-C concentrations were 1 09+/-30, 109+/-26, 108+/-31, and 112+/-29 mg/dL after consumption of t he rice bran, canola, corn, and olive oil-enriched diets, respectively . Plasma cholesterol and LDL-C concentrations were similar and statist ically indistinguishable when the subjects consumed the rice bran, can ola, and com oil-enriched diets and lower than when they consumed the olive oil-enriched diet. Concentrations of very-low-density lipoprotei n cholesterol, high-density lipoprotein cholesterol, triglyceride, LDL apolipoprotein (apo) B, apoA-I, and lipoprotein(a) and the total chol esterol to high-density lipoprotein cholesterol and apoB to apoA-I rat ios were not significantly different during consumption of the differe nt vegetable oil-enriched diets. Differences observed in the fasting s tate were maintained in the postprandial state. These data suggest tha t in middle-aged and elderly subjects with moderately elevated levels of LDL-C, consumption of diets enriched in rice bran oil results in pl asma lipid and apolipoprotein concentrations and predictive ratios of cardiovascular risk that are similar to those of more commonly used ve getable oils in the United States.