ANTIHYPERCHOLESTEROLEMIC EFFECT OF UNDIGESTED FRACTION OF SOYBEAN PROTEIN IN YOUNG FEMALE VOLUNTEERS

The significant antihypercholesterolemic effect of the undigested high molecular fraction (HMF) of soybean protein is known in rats, but suc h an effect has not been shown in humans. The present two experiments were designed to elucidate it in humans. Subjects were female universi ty students who had relatively high serum cholesterol levels for their age. In Experiment 1, subjects took 8% of their total energy from cas ein, soybean protein isolate (SPI), or HMF daily for 14 days. Five bas ic menus and snacks were cycled. Energy intakes and daily activities w ere kept constant and body weight was maintained. The HMF group showed decreased low-density lipoprotein cholesterol (LDL-C) as compared to other groups. In Experiment 2, subjects took 4% of total energy from c asein or HMF daily for a menstruation period. Five basic menus and sna cks which contained two egg yolks (about 500 mg cholesterol) were cycl ed. Energy intakes and daily activities were kept constant and body we ight was maintained. A decrease in LDL-C and an increase in high-densi ty lipoprotein cholesterol (HDL-C) were observed in the HMF group as c ompared to the casein group. Fecal acidic steroid excretion was greate r in the HMF group than in the casein group (p < 0.05). The results co nfirmed that HMF increases fecal steroid excretion and reduces serum c holesterol levels in humans.