Soy cotyledon fiber products reduce plasma lipids

Abstract

This study was designed to test the hypocholesterolemic effect of soy cotyledon fiber in the diet as ready-to-eat cereal and white bread, in free-living subjects having mildly elevated, fasting plasma total cholesterol levels. Twenty subjects completed a 15-week double-blind crossover design protocol. It consisted of two 6-week test periods and a 3-week rest period in between the two test periods. Subjects were randomly allotted to two test groups with comparable initial cholesterol levels. Fifteen grams of dietary fiber per day from soy cotyledon fiber was supplemented in three divided doses (equivalent to 20 g Fibrim ® soy fiber/day). Dietary records were kept for 3 consecutive days for each test period and were calculated using a computer program. Subjects were asked to maintain their normal eating habits and body weights throughout the 15-week protocol. There were no significant differences in nutrient intake between the two supplementation periods based on 3 day dietary records, except that the amount of fiber intake was significantly higher when soy cotyledon fiber was supplemented (24 g vs. 13 g/day). Soy cotyledon fiber supplementation did not produce visible intolerance. Body weights and blood pressures were not significantly affected. Soy cotyledon fiber supplementation significantly lowered plasma total cholesterol by 7.7% (from 240 to 222 mg/dl, P < 0.01) and LDL-cholesterol by 7.4% (from 159 to 145 mg/dl, P < 0.04). Plasma HDL-cholesterol and total triglycerides were not significantly affected. Placebo supplementation insignificantly lowered plasma total cholesterol by 1.5% ( P < 0.44) and LDL-cholesterol by 5% ( P < 0.15), but significantly increased plasma total triglycerides after 6 weeks of supplementation (+11.5%, P < 0.01). There was a significant difference in plasma total triglyceride levels between placebo and soy cotyledon fiber supplementations (+ 11.5% vs. −4.2%, P < 0.02). Results from this study agree with our previous observations that soy cotyledon fiber supplementation significantly lowers plasma total and LDL-cholesterol in people having mildly elevated plasma cholesterol levels.