The cholesterol-lowering effect of black beans (Phaseolus vulgaris, L.) without hulls in hypercholesterolemic rats.

The cholesterol-lowering property of beans has been shown in several studie s. The propose of the present work was to investigate the effect of black b eans (Phaseolus vulgaris, L.) without hulls on blood cholesterol of hyperch olesterolemic rats. Four groups of 8 male rats, Wistar strain, initial body weight of 200g were kept at +/- 25 degrees C in a light-dark cycle of 12h, for 28 days. The group Standard received a basal casein diet. Group Contro l received the basal diet added of 1% cholesterol plus 0.1% cholic acid. Th e group BE received a diet similar to the Control, substituted by 30% black beans, on dry-weight. The group SBB received black beans without hulls, eq uivalent to 30% of whole beans. The addition of cholesterol and cholic acid raised blood cholesterol levels of rats on Control diet by 58%, in relatio n to the Standard. BE diet reduced blood cholesterol by 15% (non-significan t - NS) and SBB diet reduced (p<0.05) by 35%, in relation to the Control di et. The levels of HDL-cholesterol were reduced (p<0.05) by both bean diets. SBB diet promoted a higher excretion of fecal cholesterol, compared to the Control. This suggests that beans without hulls promote a higher cholester ol output and that the whole beans, although had lowered blood cholesterol (NS),kept it in the enterohepatic circulation. The hypocholesterolemic comp ounds of beans seem to be located in the inner part of the grain. Further s tudies are necessary to identify these compounds and to elucidate their mec hanisms of action.