Effect of increasing levels of hard wheat fiber on fecal weight, minerals and steroids and gastrointestinal transit time in healthy young women.

Hard red wheat bran (HRWB) baked in a yeast-leavened bread was fed to 36 healthy young college women consuming a basal diet of traditional foods, which contained 15 +/- 3 g/d dietary fiber (DF). Three levels of HRWB were added supplying, respectively, 5.7, 17.1 and 28.5 g/d DF; an additional treatment group did not receive any HRWB. Fecal collections were carried out in the last 5 d of treatment. Fecal wet weight, fecal dry weight and fecal ash increased significantly for each increase in HRWB (P less than 0.05). Fecal dry matter percent changed significantly only at the highest level of HRWB (P less than 0.05). After accounting for the minerals in the HRWB, there was an increased fecal loss of Ca, but not of Zn, Cu, Fe or Mg compared to the women fed no HRWB. HRWB at a level of 17.2 g/d induced faster transit times (TT) than no HRWB and 66 g/d HRWB induced faster TT than either 17.2 or 39.6 g/d HRWB (P less than 0.05). Total daily fecal steroids were not altered by changes in HRWB. Daily total bile acid excretion increased significantly (P less than 0.05) at the two higher levels of HRWB due primarily to higher excretion of chenodeoxycholic acid.

Hypocholesterolemic effects of oat-bran or bean intake for hypercholesterolemic men.

Oat or bean products, rich in water-soluble fiber, have distinct hypocholesterolemic effects in humans. After a control diet, 20 hypercholesterolemic men were randomly allocated to oat-bran or bean supplemented diets for 21 days on a metabolic ward. Control and test diets provided equivalent energy, fat, and cholesterol but test diets had twice more total and 3-fold more soluble fiber. Oat-bran diets decreased serum cholesterol concentrations by 19% (p less than 0.0005) and calculated low-density lipoprotein cholesterol by 23% (p less than 0.0025). Bean diets decreased serum cholesterol concentrations by 19% (p less than 0.0005) and low-density lipoprotein cholesterol by 24% (p less than 0.0005). Oat-bran increased fecal weight by 43% but beans did not. While oat-bran increased fecal bile acid excretion, beans had the opposite effect. Oat-bran or bean supplements may have an important role in nutritional management of selected hypercholesterolemic patients.

Interactions of alfalfa plant and sprout saponins with cholesterol in vitro and in cholesterol-fed rats.

The in vitro interactions of saponins from alfalfa plant and alfalfa sprouts with cholesterol and the effects of alfalfa plant and sprout and saponin-free alfalfa plant on diet-induced liver cholesterol accumulation, bile acid excretion, and jejunal and colonic morphology were examined. Cholesterol-saponin interactions have been suggested as mechanisms for the observed hypocholesterolemic effects of alfalfa as well as the changes in intestinal morphology. Alfalfa plant saponins bound significant quantities of cholesterol both from ethanol solution and from micellar suspension. Alfalfa sprout saponins interacted with cholesterol to a lesser but significant extent. Sprout saponins also inhibited growth of Trichoderma viride significantly, another measure of saponin-cholesterol interaction. Bile acid adsorption was greatest for alfalfa plant and was not reduced by removal of saponins from the plant material. The ability of alfalfa to reduce liver cholesterol accumulation in cholesterol-fed rats was enhanced by removal of saponins and alfalfa sprouts did not prevent accumulation. Removal of saponins from alfalfa reduced the changes in intestinal morphology previously reported, but interaction with membrane cholesterol did not appear to be the cause of this effect of saponins. Saponin-cholesterol interaction is an important part of the hypocholesterolemic action of alfalfa but interaction of bile acids with other components of alfalfa may be of equal importance.