The interaction of dietary fibers and cholesterol upon the plasma lipids and lipoproteins, sterol balance, and bowel function in human subjects

dietary fiber upon cholesterol metabolism in man, six adult volunteer subjects were fed eucaloric cholesterol-free formula diets, with and without added dietary fiber for two 4-wk periods. A large quantity of dietary fiber was fed, some 60 g of plant cell wall material (or 16 g of crude fiber) derived from corn, beans, bran, pectin, and purified cellulose. This provided about five times the fiber intake of the typical American diet. The addition offiber to the cholesterol-free diet did not change either the plasma cholesterol level (171+21 mg/dl, SEM, to 167+18) or the triglyceride (103±39 to 93±27 mg/dl). The excretion of both endogenous neutral steroids and bile acids were unchanged with fiber (505±41 to 636 ±75 mg/day and 194±23 to 266±47 mg/day, respec-tively). However, total fecal steroid excretion was in-creased 699±29 to 902±64 mg/day, P < 0.025). With fiber, intestinal transit time was decreased (59±9 to 35±8 h, P < 0.005), and both the wet and dry stool weights were greatly increased. A second group of six subjects was fed similar diets containing 1,000 mg cholesterol derived from egg yolk. The addition of fiber to the 1,000-mg cholesterol diet did not alter either plasma cholesterol level (233±26 to 223±36 mg/dl) or triglyceride (102±19 to 83±11 mg/ dl). The excretion of endogenous neutral steroids (618 ±84 to 571±59 mg/day), of bile acids (423±122 to 401 ±89 mg/day), and of total fecal steroids (1,041±175 to 972±+111 mg/day) were unchanged by fiber. The ab-sorption of dietary cholesterol was not altered whe