HYPOCHOLESTEROLEMIC ACTION OF DIETARY FIBER UNRELATED TO FECAL BULKING EFFECT

Twenty-two healthy volunteers took approximately 20 g/day of concentrated dietary fiber from either carrot, cabbage, apple, bran, or guar gum or 31 g from pectin, added for 3-week periods to controlled diets. Total serum cholesterol fell by 13% on both guar and pectin (P < 0.01) with no significant change in high density lipoprotein cholesterol. Over the 3-week supplementation period, the other fibers were without effect with the exception of carrot, where both control and test high density lipoprotein levels fell (P < 0.05 and < 0.01, respectively). If, however, the 3rd week of the control was compared with the 3rd test week, the values for total cholesterol were 7% lower after apple (P < 0.02) while after carrot the high density lipoprotein cholesterol level was 10% lower than the control (P < 0.01). No significant change was seen in serum triglyceride or body weight either as judged by differences over the 3-week periods or by comparing test and control values at 3 weeks. Comparison of stool weights obtained in this study indicate that the fecal bulking action of dietary fiber is independent of its hypocholesterolaemic effect.