Effects of Soy Protein Isolate (SPI) and Casein on the Postprandial Lipemia in Normolipidemic Men.

Abstract

SummaryTo elucidate the effects of soybean protein and casein on postprandial lipemia, oral fat load tests were performed before and 3 weeks after the administration of soy protein isolate (SPI) and casein supplement to normolipidemic men. Eleven normolipidemic male subjects on otherwise identical controlled diets were assigned to either a 20g/d soy protein isolate (SPI) dietary supplement or a casein dietary supple ment for three weeks in a crossover design. Fat load tests with 40g/m2 of bovine milk fat were carried out before and after 3weeks on the ex perimental dietary supplements. Fasting plasma concentrations of lipids and apolipoproteins were not significantly different from baseline levels before or after the administration of SPI or casein supplemented diets. Neither SPI nor casein supplement affected the fasting plasma con centrations of lipids and apolipoproteins. The areas under the incre mental curve (AUIC) of triglyceride (TG) and remnant-like particles triglyceride (RLP-TG) after both experimental diets were not significantly different from those before the experimental diets. However, the AUIC of remnant-like particles cholesterol (RLP-C) showed a tendency (p= 0.07) to decrease after administration of the diet supplemented with SPI than before the diet. The AUIC of RLP-C was significantly (p<0.05) lower after the diet supplemented with SPI than after administration of the diet supplemented with casein. These results suggest that 3weeks of 20g/d SPI dietary supplement favorably affects the postprandial remnant lipoprotein response as compared to the casein dietary supplement.

Postprandial Lipemia Detects the Effect of Soy Protein on Cardiovascular Disease Risk Compared with the Fasting Lipid Profile

“…supplementation on select fasting and postprandial blood lipid and glucose concentrations in normocholesterolemic, sedentary males. Our data support the hypothesis that the postprandial state is more sensitive than the traditional lipid profile for detecting changes associated with soy consumption in this study population, which is in concurrence with previous data [48]. While fasting blood lipid and glucose concentrations did not change significantly, postprandial TAG concentration was surprisingly higher after Soy-consumption.…”

“…These data suggest that the dearth of isoflavones in Soy-may deleteriously alter postprandial processing of TAG such that over time risk for CVD potentially increases. Together, with a previous report, our data show support for measuring blood lipids in a postprandial state in order to detect changes with soy ingestion [48]. However, these changes are minimal at best in the normocholesterolemic, sedentary male, which provides credence to a recent statement by the American Heart Association; which iterated that the ingestion of soy products provides little additional, salubrious benefit beyond the typical vegetarian diet [44].…”

“…Thus, studies involving soy consumption and its effect on the traditional lipid profile may be missing a more favorable, metabolic processing of exogenous lipids. The first study to evaluate the effect of a soy protein isolate on postprandial remnantlike particles showed no change in fasting lipid concentrations but a significant and more favorable decrease in postprandial, remnant-like cholesterol concentration and area under the curve (AUC) compared with an atherogenic control (i.e., casein); after 3 weeks of supplementation in 11 Japanese males [48]. It is plausible then, that the salubrious effect of soy may be more detectable during the postprandial state rather than following an overnight fast and may be more representative of an individual's normal metabolic state.…”

Double-Blind Controlled Study on the Effects of Dietary Diacylglycerol on Postprandial Serum and Chylomicron Triacylglycerol Responses in Healthy Humans

“…Dietary fiber [16,17], glucose [18], soybean protein [19] and exercise [20,21] have been shown to reduce the magnitude of postprandial lipemia. Several recent studies have also demonstrated the acute effects of dietary fatty acids on postprandial lipemia [22][23][24][25].…”

Effects of Soy Protein on Levels of Remnant-like Particles Cholesterol and Vitamin E in Healthy Men.

“…Recently, remnant-like particles (RLP), which is the lipoprotein unbound to the immunoaffinity chromatog raphy that consists of monoclonal antibodies to apoB -100 and to apoA-1, has been used as a marker of rem nant lipoproteins (6). We have previously reported that 20g per day of SPI intake for 3 weeks improved the me tabolism of postprandial remnant lipoproteins after an oral fat load compared with casein intake and slightly reduced the fasting of RLP cholesterol, which was not significant (7). Therefore the effect of soy protein on TG or remnant lipoproteins is unclear.…”