Effects of dietary soybean globulins on plasma and liver lipids and on fecal excretion of neutral sterols in rats.

Abstract

SummaryEffects of low-fat (1% corn oil) diets containing an isonitro genous level (3.2%) of either casein, soybean protein isolate or three soybean globulin fractions (total, 11S and 7S globulins) on plasma and liver lipids and on the excretion of fecal neutral sterols were examined in rats. When diets free of cholesterol were fed, the concentration of plasma cholesterol was significantly lower in all groups of rats given different soybean proteins than in the animals given casein. 11 S globulin tended to produce a lower level of plasma cholesterol as compared with the 7S counterpart. Although the net decrease due to feeding plant proteins in high density lipoprotein cholesterol was to some extent greater than that of very low and low density lipoprotein cholesterol, the percentage of the former to total cholesterol remained in the normal range. The con centration of liver cholesterol appeared to be lower in rats given soybean proteins. Rats fed soybean globulins, as compared with the animals fed casein, tended to excrete larger amounts of neutral sterol into the feces. These soybean-effects disappeared when cholesterol and cholic acid were added to diets. The results indicated that the antihypercholesterolemic effect of soybean protein was attributable to protein per se, and not to the carbohydrate components which were associated with the protein preparation.

Mechanism for the Cholesterol-Lowering Action of Egg White Protein in Rats

“…The cholesterol-lowering action of soy protein has been investigated for a diet containing 20% soy protein in animal experiments. [13][14][15][16] Therefore, in all experiment in this series, EWP was added at the level of 20%. To the high-cholesterol diet, 0.5% cholesterol (Wako Pure Chemical Industries Ltd.) and 0.125% cholic acid (Wako Pure Chemical Industries Ltd.) were added at the expense of -cornstarch to the control diet.…”

“…If egg white protein (EWP) has a cholesterol-lowering effect, it may be of benefit during dietary therapy for hypercholesterolemia. It has been reported that such vegetable proteins as soy protein decreased the serum cholesterol concentration, [12][13][14][15][16][17] whereas such animal proteins as casein increased it. 12) Asato et al have reported that consumption of egg white compared with cheese (milk protein) reduced the serum total-and low-density lipoprotein (LDL)-cholesterol concentrations in humans.…”

Effects of arginine and lysine addition to casein and soya-bean protein on serum lipids, apolipoproteins, insulin and glucagon in rats

“…It is reasonable to consider that the different effects on plasma cholesterol are attributed in part at least to the difference in the amino acid profiles of the proteins. However, not all the available evidence supports this concept (Hevia et al 1980;Huff & Carroll, 1980;Okita & Sugano, 1981). Kritchevsky and co-workers (Kritchevsky, 1979;Czarnecki & Kritchevsky, 1980) have considered the arginine: lysine value which in soya-bean protein is twice that of casein (1.07 v. 0.48).…”

Baobab (adansonia digitata l.) Seed protein utilization in young albino rats. Ii. Haematocrit, plasma and hepatic biochemical metabolites

“…Balogun et al (1982) reported significantly higher levels of serum lipids in rats fed plant proteins as compared with rats fed similar diets containing casein as the only protein source. However, other workers observed no consistent differences in serum lipids in rats fed diets containing either plant or animal proteins (Okita and Sugano, 1981;Adeyeye et al, 1989;Dong et al, 1990).…”