The whey fermentation product malleable protein matrix decreases TAG concentrations in patients with the metabolic syndrome: a randomised placebo-controlled trial

Effects of supplementation with milk protein on glycemic parameters: a GRADE-assessed systematic review and dose-response meta-analysis

BACKGROUND

It is suggested that supplementation with milk protein (MP) has the potential to ameliorate the glycemic profile; however, the exact impact and certainty of the findings have yet to be evaluated. This systematic review and dose-response meta-analysis of randomized controlled trials (RCTs) assessed the impact of MP supplementation on the glycemic parameters in adults.

METHODS

A systematic search was carried out among online databases to determine eligible RCTs published up to November 2022. A random-effects model was performed for the meta-analysis.

RESULTS

A total of 36 RCTs with 1851 participants were included in the pooled analysis. It was displayed that supplementation with MP effectively reduced levels of fasting blood glucose (FBG) (weighted mean difference (WMD): -1.83 mg/dL, 95% CI: -3.28, -0.38; P = 0.013), fasting insulin (WMD: -1.06 uU/mL, 95% CI: -1.76, -0.36; P = 0.003), and homeostasis model assessment of insulin resistance (HOMA-IR) (WMD: -0.27, 95% CI: -0.40, -0.14; P < 0.001) while making no remarkable changes in serum hemoglobin A1c (HbA1c) values (WMD: 0.01%, 95% CI: -0.14, 0.16; P = 0.891). However, there was a significant decline in serum levels of HbA1c among participants with normal baseline body mass index (BMI) based on sub-group analyses. In addition, HOMA-IR values were significantly lower in the MP supplement-treated group than their untreated counterparts in short- and long-term supplementation (≤ 8 and > 8 weeks) with high or moderate doses (≥ 60 or 30-60 g/d) of MP or whey protein (WP). Serum FBG levels were considerably reduced upon short-term administration of a low daily dose of WP (< 30 g). Furthermore, the levels of serum fasting insulin were remarkably decreased during long-term supplementation with high or moderate daily doses of WP.

CONCLUSION

The findings of this study suggest that supplementation with MP may improve glycemic control in adults by reducing the values of fasting insulin, FBG, and HOMA-IR. Additional trials with longer durations are required to confirm these findings.

The effects of whey protein on blood pressure: A systematic review and dose-response meta-analysis of randomized controlled trials

AIMS

This systematic review and dose-response meta-analysis was conducted to summarize data from available clinical trials on the effects of whey protein (WP) supplementation on blood pressure (BP) in adults.

DATA SYNTHESIS

A comprehensive literature search was conducted in the electronic databases PubMed, Web of Science, ProQuest, Embase, and SCOPUS from inception to October 2022. Weighted mean differences (WMD) and 95% confidence intervals (CI) were calculated to assess pooled effect sizes. Heterogeneity between studies was assessed using the Cochran's Q test and I2. Subgroup analysis was performed to assess potential sources of heterogeneity. The dose-response relationship was assessed using fractional polynomial modeling. Of the 2,840 records, 18 studies with 1,177 subjects were included. Pooled analysis showed that whey protein supplementation resulted in a significant reduction in systolic blood pressure (WMD: -1.54 mmHg; 95% CI: -2.85 to -0.23, p = 0.021), with significant heterogeneity between studies (I2 = 64.2%, p < 0.001), but not for diastolic blood pressure (DBP) (WMD: -0.27 mmHg; 95% CI: -1.14, 0.59, p = 0.534) with high heterogeneity between studies (I2 = 64.8%, p < 0.001). However, WP supplementation significantly reduced DBP at a dose of ˃30 g/day, in RCTs that used WP isolate powder for their intervention, in sample sizes ≤100, in studies with an intervention duration of ≤10 weeks, and in those studies that were conducted in patients with hypertension and had participants with a BMI of 25-30 kg/m2.

CONCLUSION

This meta-analysis demonstrated that WP intake significantly reduced SBP levels. Further large-scale studies are needed to specify the exact mechanism, and optimal dosage of WP supplementation to obtain a beneficial effect on BP.

A Meta-Analysis of Microbial Therapy Against Metabolic Syndrome: Evidence From Randomized Controlled Trials

Background and aims: Metabolic syndrome (MetS), accompanied with significant intestinal dysbiosis, causes a great public health burden to human society. Here, we carried out a meta-analysis to qualify randomized controlled trials (RCTs) and to systematically evaluate the effect of microbial therapy on MetS. Methods and results: Forty-two RCTs were eligible for this meta-analysis after searching the PubMed, Cochrane, and Embase databases. Pooled estimates demonstrated that treatment with microbial therapy significantly reduced the waist circumference (WC) (SMD = -0.26, 95% CI -0.49, -0.03), fasting blood glucose (FBG) (SMD = -0.35, 95% CI -0.52, -0.18), total cholesterol (TC) (SMD = -0.36, 95% CI -0.55, -0.17), low-density lipoprotein cholesterol (LDL-C) (SMD = -0.42, 95% CI -0.61, -0.22), and triacylglycerol (TG)(SMD = -0.38, 95% CI -0.55, -0.20), but increased the high-density lipoprotein cholesterol (HDL-C) (SMD = 0.28, 95% CI.03, 0.52). Sensitivity analysis indicated that after eliminating one study utilizing Bifidobacteriumlactis, results became statistically significant in diastolic blood pressure (DBP) (SMD = -0.24, 95% CI -0.41, -0.07) and in Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) (SMD = -0.28, 95% CI -0.54, -0.03), while the body mass index (BMI) showed significant difference after eliminating one study utilizing oat bran (SMD = -0.16, 95% CI -0.31, -0.01). There was still no significant effect in systolic blood pressure (SBP) and in hemoglobin A1c (HbA1c%). Conclusion: In patients with MetS, the conditioning with microbial therapy notably improves FBG, TC, TG, HDL-C, LDL-C, WC, BMI (except for the study using oat bran), HOMA-IR, and DBP (except for the Study using Bifidobacteriumlactis), however, with no effect in SBP and in HbA1c%.

Role of Fluid Milk in Attenuating Postprandial Hyperglycemia and Hypertriglyceridemia

Postprandial plasma glucose and triglyceride concentrations are predictive of relative cardiovascular disease (CVD) risk, and the pathogenesis of both insulin resistance and atherosclerosis has been attributed to acute states of hyperglycemia and hypertriglyceridemia. Postprandial lipemia and hyperglycemia suppress vascular reactivity and induce endothelial dysfunction. Epidemiological studies suggest that chronically-high consumption of milk and milk products is associated with a reduced risk of type 2 diabetes, metabolic syndrome, and CVD. The addition of dairy products to meals high in carbohydrates and fat may lessen these risks through reductions in postprandial glucose and triglyceride responses. Purported mechanisms include dairy proteins and bioactive compounds, which may explain the inverse relationship between dairy consumption and cardiometabolic diseases. The current review evaluates the available literature describing the relationships between metabolic dysfunction, postprandial metabolism, and vascular dysfunction and discusses the potential role of milk and dairy products in attenuating these impairments.

Whey protein consumption following fasted exercise reduces early postprandial glycaemia in centrally obese males: a randomised controlled trial

Purpose

Acute submaximal exercise and whey protein supplementation have been reported to improve postprandial metabolic and appetite responses to a subsequent meal independently. We aimed to examine the combination of these strategies on postprandial responses to a carbohydrate-rich breakfast.

Methods

Twelve centrally obese males (age 41 ± 3 years, waist circumference 123.4 ± 2.9 cm), completed three trials in a single-blind, crossover design. Participants rested for 30 min (CON) or completed 30 min low–moderate-intensity treadmill walking (51 ± 1% \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\dot{V}O}}_{\text{2peak}}$$\end{document}V˙O2peak) followed immediately by ingestion of 20 g whey protein (EX + PRO) or placebo (EX). After 15 min, a standardised breakfast was consumed and blood, expired gas and subjective appetite were sampled postprandially. After 240 min, an ad libitum lunch meal was provided to assess energy intake.

Results

During EX + PRO, post-breakfast peak blood glucose was reduced when compared with EX and CON (EX + PRO: 7.6 ± 0.4 vs EX: 8.4 ± 0.3; CON: 8.3 ± 0.3 mmol l⁻¹, p ≤ 0.04). Early postprandial glucose AUC_0–60 min was significantly lower under EX + PRO than EX (p = 0.011), but not CON (p = 0.12). Over the full postprandial period, AUC_0–240 min during EX + PRO did not differ from other trials (p > 0.05). Peak plasma insulin concentrations and AUC_0–240 min were higher during EX + PRO than CON, but similar to EX. Plasma triglyceride concentrations, substrate oxidation and subjective appetite responses were similar across trials and ad libitum energy intake was not influenced by prior fasted exercise, nor its combination with whey protein supplementation (p > 0.05).

Conclusion

Following fasted low–moderate-intensity exercise, consuming whey protein before breakfast may improve postprandial glucose excursions, without influencing appetite or subsequent energy intake, in centrally obese males.

Trial registration number

NCT02714309.

The effect of whey protein on the components of metabolic syndrome in overweight and obese individuals; a systematic review and meta-analysis

BACKGROUND

The risk of developing chronic diseases such as diabetes, cardiovascular disease, dyslipidemia, and stroke is increased following an outbreak of metabolic syndrome. Whey protein can play a major role in preventing metabolic syndrome.

OBJECTIVE

This study was conducted to systematically evaluate the effect of whey protein on the components of metabolic syndrome in overweight and obesity patients.

METHODS

This systematic review and meta-analysis was conducted on RCTs (PROSPERO registration number: CDR42019114794). Published articles of controlled trials between 1 January 2000 to 30 May 2019 indexed in PubMed, Scopus, Web of Science and Cochrane Library were reviewed. Keywords were Whey Protein, Metabolic Syndrome, HDL Lipoprotein, Blood Pressure, Triglyceride, Fasting Blood Glucose, Waist Circumference, Overweight and Obesity or a combination of them in the title/abstracts. The mean difference was extracted for each study. All analyses performed using STATA version 11.

RESULTS

There were 2344 individuals reviewed in this systematic review of 37 published articles.

CONCLUSION

According to the results, whey supplementation significantly reduced the SBP, DBP, HDL, waist circumference, TG and FBS in intervention groups in comparing to control groups.

The role of whey protein in postprandial glycaemic control

Epidemiological studies demonstrate that poor glycaemic control is an independent risk factor for CVD. Postprandial glycaemia has been demonstrated as a better predictor of glycated Hb, the gold standard of glycaemic control, when compared with fasting blood glucose. There is a need for more refined strategies to tightly control postprandial glycaemia, particularly in those with type 2 diabetes, and nutritional strategies around meal consumption may be effective in enhancing subsequent glycaemic control. Whey protein administration around meal times has been demonstrated to reduce postprandial glycaemia, mediated through various mechanisms including an enhancement of insulin secretion. Whey protein ingestion has also been shown to elicit an incretin effect, enhancing the secretion of glucose-dependent insulinotropic peptide and glucagon-like peptide-1, which may also influence appetite regulation. Acute intervention studies have shown some promising results however many have used large dosages (50-55 g) of whey protein alongside high-glycaemic index test meals, such as instant powdered potato mixed with glucose, which does not reflect realistic dietary strategies. Long-term intervention studies using realistic strategies around timing, format and amount of whey protein in relevant population groups are required.

Whey protein lowers blood pressure and improves endothelial function and lipid biomarkers in adults with prehypertension and mild hypertension: results from the chronic Whey2Go randomized controlled trial

BACKGROUND

Cardiovascular diseases (CVDs) are the greatest cause of death globally, and their reduction is a key public-health target. High blood pressure (BP) affects 1 in 3 people in the United Kingdom, and previous studies have shown that milk consumption is associated with lower BP.

OBJECTIVE

We investigated whether intact milk proteins lower 24-h ambulatory blood pressure (AMBP) and other risk markers of CVD.

DESIGN

The trial was a double-blinded, randomized, 3-way-crossover, controlled intervention study. Forty-two participants were randomly assigned to consume 2 × 28 g whey protein/d, 2 × 28 g Ca caseinate/d, or 2 × 27 g maltodextrin (control)/d for 8 wk separated by a 4-wk washout. The effects of these interventions were examined with the use of a linear mixed-model ANOVA.

RESULTS

Thirty-eight participants completed the study. Significant reductions in 24-h BP [for systolic blood pressure (SBP): -3.9 mm Hg; for diastolic blood pressure (DBP): -2.5 mm Hg; P = 0.050 for both)] were observed after whey-protein consumption compared with control intake. After whey-protein supplementation compared with control intake, peripheral and central systolic pressures [-5.7 mm Hg (P = 0.007) and -5.4 mm Hg (P = 0.012), respectively] and mean pressures [-3.7 mm Hg (P = 0.025) and -4.0 mm Hg (P = 0.019), respectively] were also lowered. Flow-mediated dilation (FMD) increased significantly after both whey-protein and calcium-caseinate intakes compared with control intake [1.31% (P < 0.001) and 0.83% (P = 0.003), respectively]. Although both whey protein and calcium caseinate significantly lowered total cholesterol [-0.26 mmol/L (P = 0.013) and -0.20 mmol/L (P = 0.042), respectively], only whey protein decreased triacylglycerol (-0.23 mmol/L; P = 0.025) compared with the effect of the control. Soluble intercellular adhesion molecule 1 and soluble vascular cell adhesion molecule 1 were reduced after whey protein consumption (P = 0.011) and after calcium-caseinate consumption (P = 0.039), respectively, compared with after control intake.

CONCLUSIONS

The consumption of unhydrolyzed milk proteins (56 g/d) for 8 wk improved vascular reactivity, biomarkers of endothelial function, and lipid risk factors. Whey-protein supplementation also lowered 24-h ambulatory SBP and DBP. These results may have important implications for public health. This trial was registered at clinicaltrials.gov as NCT02090842.

Can milk proteins be a useful tool in the management of cardiometabolic health? An updated review of human intervention trials

The prevalence of cardiometabolic diseases is a significant public health burden worldwide. Emerging evidence supports the inverse association between greater dairy consumption and reduced risk of cardiometabolic diseases. Dairy proteins may have an important role in the favourable impact of dairy on human health such as blood pressure (BP), blood lipid and glucose control. The purpose of this review is to update and critically evaluate the evidence on the impacts of casein and whey protein in relation to metabolic function. Evidence from short-term clinical studies assessing postprandial responses to milk protein ingestion suggests benefits on vascular function independent of BP, as well as improvement in glycaemic homeostasis. Long-term interventions have been less conclusive, with some showing benefits and others indicating a lack of improvement in vascular function. During chronic consumption BP appears to be lowered and both dyslipidaemia and hyperglacaemia seem to be controlled. Limited number of trials investigated the effects of dairy proteins on oxidative stress and inflammation. Although the underlying mechanisms of milk proteins on cardiometabolic homeostasis remains to be elucidated, the most likely mechanism is to improve insulin resistance. The incorporation of meals enriched with dairy protein in the habitual diet may result in the beneficial effects on cardiometabolic health. Nevertheless, future well-designed, controlled studies are needed to investigate the relative effects of both casein and whey protein on BP, vascular function, glucose homeostasis and inflammation.

Effect of whey protein on blood lipid profiles: a meta-analysis of randomized controlled trials

Previous studies have suggested that whey supplementation may have beneficial effects on lipid profiles, although results were inconsistent. A literature search was performed in March 2015 for randomized controlled trials observing the effects of whey protein and its derivatives on circulating levels of triacylglycerol (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). A meta-analysis was subsequently conducted. The meta-analysis results of 13 trials showed that whey supplementation significantly reduced the circulating TG level by 0.11 mmol/l (95% CI: -0.21, 0 mmol/l), whereas the whey protein had no effects on circulating TC (-0.11 mmol/l, 95% CI: -0.27, 0.05 mmol/l), LDL-C (-0.08 mmol/l, 95% CI: -0.23, 0.07 mmol/l) and HDL-C (0.01 mmol/l, 95% CI: -0.04, 0.05 mmol/l). Subgroup analysis showed that significant TG reduction disappeared in participants with low body mass index, low supplemental whey dose or under exercise training/energy restriction during the trial. No evidence of heterogeneity across studies and publication bias was observed. In conclusion, our findings demonstrated that the effects of whey protein supplementation were modest, with an overall lowering effect on TG but no effect on TC, LDL-C and HDL-C.

Nutrition and Inflammation in Older Individuals: Focus on Vitamin D, n-3 Polyunsaturated Fatty Acids and Whey Proteins

Chronic activation of the inflammatory response, defined as inflammaging, is the key physio-pathological substrate for anabolic resistance, sarcopenia and frailty in older individuals. Nutrients can theoretically modulate this phenomenon. The underlying molecular mechanisms reducing the synthesis of pro-inflammatory mediators have been elucidated, particularly for vitamin D, n-3 polyunsaturated fatty acids (PUFA) and whey proteins. In this paper, we review the current evidence emerging from observational and intervention studies, performed in older individuals, either community-dwelling or hospitalized with acute disease, and evaluating the effects of intake of vitamin D, n-3 PUFA and whey proteins on inflammatory markers, such as C-Reactive Protein (CRP), interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α). After the analysis, we conclude that there is sufficient evidence for an anti-inflammatory effect in aging only for n-3 PUFA intake, while the few existing intervention studies do not support a similar activity for vitamin D and whey supplements. There is need in the future of large, high-quality studies testing the effects of combined dietary interventions including the above mentioned nutrients on inflammation and health-related outcomes.

The scale of the evidence base on the health effects of conventional yogurt consumption: findings of a scoping review

BACKGROUND

The health effects of conventional yogurt have been investigated for over a century; however, few systematic reviews have been conducted to assess the extent of the health benefits of yogurt.

OBJECTIVE

The aim of this scoping review was to assess the volume of available evidence on the health effects of conventional yogurt.

METHODS

The review was guided by a protocol agreed a priori and informed by an extensive literature search conducted in November 2013. Randomized controlled trials were selected and categorized according to the eligibility criteria established in the protocol.

RESULTS

213 studies were identified as relevant to the scoping question. The number of eligible studies identified for each outcome were: bone health (14 studies), weight management and nutrition related health outcomes (81 studies), metabolic health (6 studies); cardiovascular health (57 studies); gastrointestinal health (24 studies); cancer (39 studies); diabetes (13 studies), Parkinson's disease risk (3 studies), all-cause mortality (3 studies), skin complaints (3 studies), respiratory complaints (3 studies), joint pain/function (2 studies); the remaining 8 studies reported a variety of other outcomes. For studies of a similar design and which assessed the same outcomes in similar population groups, we report the potential for the combining of data across studies in systematic reviews.

CONCLUSIONS

This scoping review has revealed the extensive evidence base for many outcomes which could be the focus of systematic reviews exploring the health effects of conventional yogurt consumption.

Effect of whey supplementation on circulating C-reactive protein: a meta-analysis of randomized controlled trials

Whey supplementation is beneficial for human health, possibly by reducing the circulating C-reactive protein (CRP) level, a sensitive marker of inflammation. Thus, a meta-analysis of randomized controlled trials was conducted to evaluate their relationship. A systematic literature search was conducted in July, 2014, to identify eligible studies. Either a fixed-effects model or a random-effects model was used to calculate pooled effects. The meta-analysis results of nine trials showed a slight, but no significant, reduction of 0.42 mg/L (95% CI −0.96, 0.13) in CRP level with the supplementation of whey protein and its derivates. Relatively high heterogeneity across studies was observed. Subgroup analyses showed that whey significantly lowered CRP by 0.72 mg/L (95% CI −0.97, −0.47) among trials with a daily whey dose ≥20 g/day and by 0.67 mg/L (95% CI −1.21, −0.14) among trials with baseline CRP ≥3 mg/L. Meta-regression analysis revealed that the baseline CRP level was a potential effect modifier of whey supplementation in reducing CRP. In conclusion, our meta-analysis did not find sufficient evidence that whey and its derivates elicited a beneficial effect in reducing circulating CRP. However, they may significantly reduce CRP among participants with highly supplemental doses or increased baseline CRP levels.

Milk protein for improved metabolic health: a review of the evidence

Epidemiological evidence shows that consumption of dairy products is associated with decreased prevalence of metabolic related disorders, whilst evidence from experimental studies points towards dairy protein as a dietary component which may aid prevention of type 2 diabetes (T2DM). Poor metabolic health is a common characteristic of overweight, obesity and aging, and is the forerunner of T2DM and cardiovascular disease (CVD), and an ever increasing global health issue. Progressive loss of metabolic control is evident from a blunting of carbohydrate, fat and protein metabolism, which is commonly manifested through decreased insulin sensitivity, inadequate glucose and lipid control, accompanied by a pro-inflammatory environment and hypertension. Adverse physiological changes such as excess visceral adipose tissue deposition and expansion, lipid overspill and infiltration into liver, muscle and other organs, and sarcopaenia or degenerative loss of skeletal muscle mass and function all underpin this adverse profile. ‘Sarcobesity’ and sarcopaenic diabetes are rapidly growing health issues. As well as through direct mechanisms, dairy protein may indirectly improve metabolic health by aiding loss of body weight and fat mass through enhanced satiety, whilst promoting skeletal muscle growth and function through anabolic effects of dairy protein-derived branch chain amino acids (BCAAs). BCAAs enhance muscle protein synthesis, lean body mass and skeletal muscle metabolic function. The composition and processing of dairy protein has an impact on digestion, absorption, BCAA kinetics and function, hence the optimisation of dairy protein composition through selection and combination of specific protein components in milk may provide a way to maximize benefits for metabolic health.

Recent advances in dietary proteins and lipid metabolism

PURPOSE OF REVIEW

There is growing interest in defining the dietary approaches for the management of lipid disorders. This review focuses on dietary proteins.

RECENT FINDINGS

Increasing protein intake was coupled with improved lipid profiles in humans and animals. However, most studies increased the protein content by reducing that of fat or carbohydrate or both, making unclear the role of protein alone. Mechanisms of action differ with the sources of proteins, because of amino acid composition and bioactive peptides encrypted in their sequences. Soy protein was investigated the most, and many studies show that its consumption reduces blood cholesterol. The role of other constituents including isoflavones is debated. Short-term studies are consistent in showing lipid-lowering properties of whey proteins, attributed to their relative high content in branched chain amino acids. A limited number of studies, the majority being on animals, have shown hypocholesterolemic activities of fish proteins.

SUMMARY

Dietary proteins regulate lipid metabolism in a manner dependent on their quantity and composition. There is a general consensus that proteins slow lipid absorption and synthesis, and promote lipid excretion. The benefits of dietary proteins remain to be confirmed in individuals with lipid abnormalities, for formulation of optimal dietary alternatives for the management of lipid disturbances.