This study examined the hypocholesterolemic effect and hormonal changes resulting from 30 d of supplementation with Vicia faba L. (field bean) flour of diets of young men (aged 18-21 y; n = 40) with borderline-high or high serum cholesterol values. All subjects (groups A-D) consumed the same basic diet. Additionally, volunteers in the control group (A) consumed 90 g control flour/d whereas those in the three bean groups received either 90 g cooked field bean flour (groups B and C) or 90 g raw field bean flour (group D) daily. Groups A and B included volunteers with borderline-high cholesterol values [5.2-6.2 mmol total cholesterol/L and 3.4-4.1 mmol low-density-lipoprotein (LDL) cholesterol/L]. Subjects in groups C and D had high serum cholesterol concentrations (total cholesterol>> 6.2 mmol/L and LDL cholesterol>> 4.1 mmol/L). After 30 d, serum glucose, insulin, triacylglycerol, total, LDL-cholesterol, and very-low-density-lipoprotein (VLDL)-cholesterol values were significantly lower than initial values in all subjects who consumed diets containing field bean flour (P < or = 0.0001, except for LDL-cholesterol concentrations in group C, for which P < or = 0.0007). Legume intake also resulted in a significant increase (P < or = 0.0001) in glucagon and high-density-lipoprotein cholesterol. Neither cortisol nor thyroid hormone values changed significantly. The results suggest that the hypocholesterolemic effect of field bean intake depends at least partly on a concomitant increase in glucagon and decrease in insulin values. The more marked reduction in triacylglycerol and VLDL-cholesterol concentrations in subjects who consumed raw field beans indicates a coparticipation of their thermolabile components.