SOYBEAN PROTEIN LOWERS SERUM-CHOLESTEROL LEVELS IN HAMSTERS - EFFECT OF DEBITTERED UNDIGESTED FRACTION

The undigested fraction (UDF) of soybean protein exerts a marked hypoc holesterolemic effect in relation to soybean protein (SOY) in rats. Th e present study was conducted to confirm whether UDF was effective in hamsters as in rats in combination with different fat sources, either perilla oil (PER) or safflower oil (SAF). Because the hamster, unlike the rat, disliked the bitter taste of UDF, the effect of debittering U DF also was studied. Cholesterol-enriched (0.2%) diets containing 20% protein and 10% fat were fed to hamsters for 4 wk. UDF was more hypoch olesterolemic than soybean protein in hamsters regardless of the dieta ry fat source. The ratio of high-density lipoprotein to total choleste rol essentially remained unchanged. The debittered UDF, without influe ncing food intake and thereby weight gain, exerted a significant hypoc holesterolemic effect comparable with UDF in relation to SOY accompany ing stimulation of fecal neutral and acidic steroid excretion. The fat ty acid composition of liver phospholipids was influenced by the type of the dietary protein, and both UDF seemed to interfere characteristi cally more than SOY with the desaturation systems between linoleic aci d and arachidonic acid. Thus, the debittered UDF, similar to UDF, exer ted a distinct influence on the various parameters of lipid metabolism in relation to SOY. (C) Elsevier Science Inc. 1997.