Effects of soy protein isolate (SPI) and casein on the postprandial lipemia in normolipidemic men

Correlation between estimated plasma remnant-like particle cholesterol and vegetable fat intake in Uku town, Japan

Background

Remnant-like particle cholesterol (RLP-C) is highly atherogenic, which is associated with atherosclerosis. However, RLP-C has not been routinely measured in the clinical practice. We estimated RLP-C levels using conventional lipid profiles and examined the association between estimated RLP-C and related factors including nutrient intake.

Methods

This study was performed in Uku town, Nagasaki prefecture, Japan in 2019. A total of 225 subjects were enrolled and directly measured RLP-C levels. Estimated RLP-C levels were defined as the following formula [total cholesterol − (LDL-cholesterol) − (HDL-cholesterol)]. Multivariate analyses were used to assess the relationship between estimated RLP-C and atherogenic factors. We calculated cut-off values on dichotomized RLP-C (< 7.5 mg/dL vs. ≥ 7.5 mg/dL) by receiver operating characteristic (ROC) curve.

Results

The mean values of directly measured RLP-C levels and estimated RLP-C were 4.0 mg/dL and 16.4 mg/dL, respectively. In the multiple stepwise linear regression analysis, directly measured and estimated RLP-C levels were independently and commonly associated with apolipoprotein E, triglycerides, and vegetable fat intake (inversely). Using ROC curves, we found the cut-off value of estimated RLP-C was 22.0 mg/dL.

Conclusion

We demonstrated that the estimated RLP-C levels using conventional lipid profiles may substitute for directly measured RLP-C and these levels were independently and inversely associated with vegetable fat intake in the community-dwelling Japanese population.

Response to an oral fat load and effects on lipid profile, glycemia and high-sensitivity C-reactive protein after soybean extract consumption

INTRODUCTION

The aim of this study was to evaluate the response in terms of lipid profile, glycemia and high-sensitivity C-reactive protein after an oral fat load (OFL) with a non-dairy cheese cream containing fermented soybean extract soy, compared to a dairy cheese.

MATERIAL AND METHODS

One hundred twenty-four healthy subjects underwent an OFL performed using a mixture containing non-dairy cheese cream, containing 75% fermented soybean extract (Valsoia Lo spalmabile), or a dairy cheese cream.

RESULTS

During the OFL, total cholesterol and triglycerides at 6 h were lower with non-dairy cheese cream containing fermented soybean compared to dairy cheese cream. The value of low-density lipoprotein cholesterol recorded at 6 h with the active treatment was lower than the one recorded at the same time with the dairy cheese cream. A decrease of high-density lipoprotein cholesterol (HDL-C) was recorded with the dairy cheese cream, but not with the active treatment; moreover, the HDL-C value recorded with the active treatment was higher than the one observed with the dairy cheese cream. There was an increase of high-sensitivity C-reactive protein (hs-CRP) at 3, 6, and 9 h compared to 0 h with the dairy cheese cream, but not with the active treatment. The hs-CRP value observed with the active treatment was lower than the one observed with the dairy cheese cream.

CONCLUSIONS

A non-dairy cheese cream, containing 75% fermented soybean extract, caused a minor increase of lipid profile and of hs-CRP during OFL compared to a dairy cheese cream in healthy subjects.

Effect of Plant Protein on Blood Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

There is a heightened interest in plant-based diets for cardiovascular disease prevention. Although plant protein is thought to mediate such prevention through modifying blood lipids, the effect of plant protein in specific substitution for animal protein on blood lipids remains unclear. To assess the effect of this substitution on established lipid targets for cardiovascular risk reduction, we conducted a systematic review and meta-analysis of randomized controlled trials using the Grading of Recommendations Assessment, Development, and Evaluation system.

METHODS AND RESULTS

MEDLINE, EMBASE, and the Cochrane Registry were searched through September 9, 2017. We included randomized controlled trials of ≥3 weeks comparing the effect of plant protein in substitution for animal protein on low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B. Two independent reviewers extracted relevant data and assessed risk of bias. Data were pooled by the generic inverse variance method and expressed as mean differences with 95% confidence intervals. Heterogeneity was assessed (Cochran Q statistic) and quantified (I2 statistic). The overall quality (certainty) of the evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation system. One-hundred twelve randomized controlled trials met the eligibility criteria. Plant protein in substitution for animal protein decreased low-density lipoprotein cholesterol by 0.16 mmol/L (95% confidence interval, -0.20 to -0.12 mmol/L; P<0.00001; I2=55%; moderate-quality evidence), non-high-density lipoprotein cholesterol by 0.18 mmol/L (95% confidence interval, -0.22 to -0.14 mmol/L; P<0.00001; I2=52%; moderate-quality evidence), and apolipoprotein B by 0.05 g/L (95% confidence interval, -0.06 to -0.03 g/L; P<0.00001; I2=30%; moderate-quality evidence).

CONCLUSIONS

Substitution of plant protein for animal protein decreases the established lipid targets low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B. More high-quality randomized trials are needed to improve our estimates.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02037321.

Dietary diacylglycerol induces the regression of atherosclerosis in rabbits

Recent studies of the relation between serum triacylglycerol concentration and the risk for coronary artery disease suggest that inefficient clearance of postprandial triacylglycerols promotes atherogenesis. We recently demonstrated that dietary diacylglycerol (DAG), rich in the 1,3-species, suppresses the postprandial increase in serum triacylglycerol levels compared with dietary triacylglycerol (TAG). Here, we investigated the effects of dietary DAG on atherosclerosis in rabbits with cholesterol-induced atherosclerosis. New Zealand White rabbits (n = 20) were fed a diet containing 3% lard and 1.3% cholesterol for 50 d to induce atherosclerotic lesions. Thereafter, the rabbits were assigned to 2 groups and fed 90 g/d nonpurified diet and orally administered 5 g DAG or TAG for an additional 34 d. Reference rabbits (n = 5) were fed only the nonpurified diet throughout the 84-d study. The area of atherosclerotic lesions and aortic lipid concentrations were significantly lower in DAG-fed rabbits compared with TAG-fed rabbits. The VLDL receptor and macrophage antigen-1 mRNA expression levels were significantly lower in DAG-fed rabbits than in TAG-fed rabbits. In the liver of DAG-fed rabbits, the triacylglycerol concentration was lower and the carnitine palmitoyltransferase activity higher than in TAG-fed rabbits. Stimulation of hepatic lipid catabolism might be related to the reduced lipid accumulation in the liver and aorta by reducing the release of triacylglycerol into the circulation. Thus, long-term consumption of DAG, which reduces postprandial lipemia, might be useful for the regression of atherosclerosis by stimulating hepatic lipid catabolism and thereby modulating monocyte/macrophage migration and aortic lipid accumulation.

Effect of tea catechins on postprandial plasma lipid responses in human subjects

Epidemiological surveys suggest that a higher intake of tea may be associated with a lower risk of CHD. There is accumulating evidence that postprandial lipaemia makes a substantial contribution to the incidence of CHD. Our aim was, therefore, to evaluate the effect of tea catechins (major ingredients in green tea) on postprandial lipid responses in human subjects after the consumption of test meals. In a randomized triple-crossover design, nine male subjects with mild or borderline hypertriacylglycerolaemia consumed 10 (control), 224 (moderate dose) and 674 mg (high dose) of the assigned tea catechins three times each along with a standardized light meal consisting of a piece of bread spread with 20 g butter. Plasma lipids were measured in the fasting state and 1, 2, 3, 4 and 6 h after consuming the light meal. Results showed that, compared with the control, moderate and high doses of tea catechins reduced the incremental area under the plasma triacylglycerol curves by 15·1 and 28·7 %, respectively. Next, the rapid elevation of remnant-like particle cholesterol was significantly inhibited by a high dose of tea catechins 2 h after consuming the light meal (P<0·01). In the range of tea catechin dosages, no significant differences were observed in the postprandial responses for plasma total cholesterol or NEFA at any time point. In conclusion, this trial demonstrated that tea catechins attenuated the postprandial increase in plasma triacylglycerol levels following a fat load. These results may provide evidence for one of the possible mechanisms involved in lowering the incidence of CVD, and may prove useful in further studies on the beneficial health effects of tea drinking.

Dietary protein type and cardiovascular disease risk factors

Observational studies suggested a negative association between vegetable protein and cardiovascular disease risk, whereas intervention studies have been less consistent. The majority of interventional studies that have evaluated the effects of soy protein compared to animal protein have used casein. Relative to casein, the effect of soy protein on lipids and lipoprotein appears to be variable and less dramatic than originally reported. When compared to animal proteins other than casein, relatively large intakes of soy protein (>/=25 g/d) appear to have a consistent, albeit small ( asymptotically equal to 5%), hypocholesterolemic effect. When assessed, no consistent additional benefit of soy protein on other cardiovascular disease risk factors; Lp(a), inflammatory markers, biomarkers of oxidative stress and endothelial function, has been reported. The data available on the effect of dietary protein on plasma lipids, lipoprotein levels, and cardiovascular disease risk factors is difficult to interpret and insufficient to account for the discrepancy between the observational and interventional studies.

Dietary compounds in relation to dietary diversity and human health

The human diet contains numerous endocrine-active compounds that influence mammalian physiology. The effects of these dietary compounds may be mediated by interaction with well-characterized intracellular hormone receptors or by other effects on patterns of endogenous hormone production, metabolism, target tissue signaling, growth, or differentiation. Because humans evolved as omnivores, the spectrum of dietary compounds that can be tolerated at modest levels of intake without frank toxicity is broad. Modest intake of these diverse nonnutritive endocrine-active compounds offers potential human health benefits through modulation of metabolic and hormonal responses, especially in sedentary individuals consuming a highly refined diet.

Double-blind controlled study on the effects of dietary diacylglycerol on postprandial serum and chylomicron triacylglycerol responses in healthy humans

OBJECTIVE

The effects of dietary diacylglycerol (DG) on postprandial lipemia in healthy humans were investigated.

METHODS

Forty normolipidemic male volunteers ingested fat emulsions containing either DG oil or triacylglycerol (TG) oil, at different doses: 10 g (n = 13), 20 g (n = 10) and 44 g (n = 17). Two test emulsions were given at seven-days intervals in random order. Fatty acid compositions of the test oils had been adjusted to be equal. Fasting and postprandial serum lipid concentrations in each group and plasma lipoprotein lipids in the 20 g-fat ingestion group were measured during the postprandial intervals.

RESULTS

When DG emulsion was ingested, serum TG concentrations were significantly lower (p < 0.05) in the late postprandial phase, i.e., 4 hours, 6 hours as compared to the TG emulsion. The magnitude of postprandial lipemia (the area bounded by the curve above the fasting concentration) after ingestion of 44 g-DG emulsion was significantly less than that of 44 g-TG emulsion (6.54 +/- 5.12 and 8.45 +/- 7.54 mmol x h/L, mean +/- SD, respectively). Chylomicron TG, cholesterol, and phospholipid concentrations at 4 hours after ingestion of DG emulsion were significantly lower (p < 0.05) than those after the ingestion of TG emulsion at the same time point. No marked differences were observed for VLDL, LDL and HDL lipids between the test emulsions.

CONCLUSION

In the usual range of fat intake (10-44 g), postprandial response after ingestion of DG emulsion was significantly less than that after ingestion of TG emulsion in healthy human subjects.

Endothelium-dependent flow-mediated vasodilation in the postprandial state in type 2 diabetes mellitus

This study examined the effects of fat- plus sucrose-rich meals on endothelium-dependent flow-mediated vasodilation in diabetic patients. Flow-mediated vasodilation in the postprandial state decreased significantly, and the decrease correlated inversely with the magnitude of postprandial hyperglycemia, suggesting that endothelial function in diabetic patients becomes impaired postprandially.