The effect of grape products on liver enzymes: A systematic review and meta-analysis of randomized controlled trials

The favorable influence of grape consumption on metabolic diseases has previously been shown in studies. We sought to assess the effects of grape intake on liver enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), in adults. We performed literature search in online databases, to find eligible randomized controlled trials (RCTs). we considered RCTs that met the following criteria: RCTs consisted of use of grape products on ALT, AST, and ALP in adults (≥18 years) with at least 2 weeks intervention duration. Pooling data from 11 trials showed that grape products intake significantly reduced ALP (p = .010), without any significant changes in ALT (p = .234) and AST (p = .300). In subgroup analysis, we found a significant reduction in ALP, ALT, and AST when the duration of intervention was ≥12 weeks, and when grape seed extract (GSE) was administered. The variable duration and dosage of intervention was one of the sources of bias in our meta-analysis. Additionally, participants involved in included studies had different physiological status and various age groups. Grape products administration may significantly improve ALT, AST, and ALP in adults in long-term interventions and/or when GSE is administered. It should be noted that the favorable effects of grape consumption were small and may not reach clinical importance.

The effects of resveratrol supplementation in patients with type 2 diabetes, metabolic syndrome, and nonalcoholic fatty liver disease: an umbrella review of meta-analyses of randomized controlled trials

BACKGROUND

Uncertainty remains about the estimates of the effects for resveratrol supplementation, including the certainty of the evidence for each estimate and the magnitude of the observed impact based on the minimal important difference.

OBJECTIVE

We aimed to provide an overview of the effects of resveratrol supplementation, in comparison to control groups, for the management of cardiometabolic risk factors in patients with type 2 diabetes (T2D), metabolic syndrome (MetS), and nonalcoholic fatty liver disease (NAFLD).

METHODS

PubMed, Scopus, and ISI Web of Science were searched from inception to May 2021. For each meta-analysis, the mean difference and its 95% CI were recalculated using a random-effects model. The certainty of evidence was rated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach.

RESULTS

We identified 11 meta-analyses corresponding to 29 outcomes in 1476 individuals with T2D, 17 meta-analyses reporting 26 outcomes in 727 participants with the MetS, and 10 meta-analyses reporting 24 outcomes in 271 patients with NAFLD. Resveratrol supplementation had beneficial effects on some outcomes such as blood pressure, lipid profile, glycemic control, and insulin resistance in T2D, waist circumference in MetS, and body-weight and inflammation markers in NAFLD; however, for almost all outcomes, the magnitude of the effect was trivial, the certainty of evidence was very low to low, or the number of trials was too few. In the case of glycated hemoglobin (HbA1c), there was evidence that resveratrol can exert favorable and clinically important effects in the short term (<12 wk; mean difference: -1.05%, 95% CI: -2.09%, -0.02%; n = 6; GRADE = moderate).

CONCLUSIONS

Current evidence does not support supplementation with resveratrol for the management of cardiometabolic risk factors in patients with T2D, MetS, and NAFLD. In the case of HbA1c, subject to the limitations such as short-term follow-up and small sample size, there was a clinically important effect. The protocol of the present systematic review was registered in Open Science Framework (https://osf.io/ake85; registration doi: 10.17605/OSF.IO/AKE85).

Targeting dyslipidemia by herbal medicines: A systematic review of meta-analyses

ETHNOPHARMACOLOGICAL RELEVANCE

The worldwide increasing prevalence of dyslipidemia has become a global health concern. Various herbal remedies have been claimed to be effective for the treatment of dyslipidemia in traditional and folkloric medicine of different regions clinical trials have been conducted to investigate their efficacy. The aim of the current systematic review is to critically assess the meta-analyses of controlled trials (CT) evaluated herb medicines for dyslipidemia.

MATERIALS AND METHODS

Relevant studies from Web of Science, PubMed, Scopus, and Cochrane Library databases based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist until January 2021 have been searched. All meta-analyses which pooled studies on the effect of herbal medicines on lipid profile including total cholesterol (TC), triglyceride (TG), and low- or high-density lipoprotein cholesterol (LDL-C, HDL-C) were also included. Meta-analyses of in vitro, animal or observational studies were excluded.

RESULTS

The overall of 141 meta-analyses were revealed. Vegetable oils, phytosterols, tea, soy protein, nuts, and curcumin have been studied frequently among the herbal medicines. Among 13 meta-analyses on vegetable oils, the greater reduce of TC (18.95 mg/dl), LDL-C (16.24 mg/dl) and TG (13.69 mg/dl) were exhibited from sunflower oil. Furthermore, rice bran oil (6.65 mg/dl) increased HDL-C significantly. Phytosterols in 12 meta-analyses demonstrated significant improvements in reducing TC, LDL-C and TG as 16.4, 23.7, and 8.85 mg/dl, respectively, and rise in HDL-C as 10.6 mg/dl. The highest reduction in serum level of TC, LDL-C and TG was reported while intake Green tea; 27.57, 24.75, and 31.87 mg/dl, accordingly within 9 meta-analyses. Average improvement of lipid profiles by 6 meta-analyses on plant proteins were 23.2, 21.7, 15.06, and 1.55 mg/dl for TC, LDL-C, TG, and HDL-C, respectively. Among 11 meta-analyses on nuts, almond showed better and significant alleviations in TC (10.69 mg/dl), walnut in LDL-C (9.23 mg/dl), pistachio in TG (22.14 mg/dl), and peanut in HDL-C (2.72 mg/dl). Overall, Curcumin, Curcuminoid, and Turmeric have resulted in the reduction of TC (25.13 mg/dl), LDL-C (39.83 mg/dl), TG (33.65 mg/dl), and an increase in the HDL-C (4.31 mg/dl).

CONCLUSION

The current systematic review shed light on the use of herbal medicines for the management of dyslipidemia. However, more well-conducted CTs are required to determine effective doses of herbal medicines.

The effect of almond intake on lipid profile: a systematic review and meta-analysis of randomized controlled trials

A number of clinical trials have examined the effect of almond intake on lipid profile in recent years; however, the results remain equivocal. Therefore, the present study aims to summarize and quantitatively examine the available evidence on the effectiveness of almond intake on lipid parameters by employing a systematic review and meta-analytic approach. Online databases including PubMed, Scopus, Embase, and Cochrane Library were searched up to September 2020 for randomized controlled trials that examined the effect of almond intake on lipid profile in adults. Treatment effects were expressed as weighted mean difference (WMD) and the corresponding standard error (SE) in the concentrations of serum lipids. To estimate the overall effect of almond intake, we employed the random-effect model. In total, 27 studies with 36 effect sizes were included in our analysis (1154 cases and 904 control subjects). The meta-analysis revealed that almond intake significantly changed the concentrations of triglycerides (WMD = -6.68 mg dL-1; 95% CI: -11.62, -1.75, p = 0.008), total cholesterol (WMD = -4.92 mg dL-1; 95% CI: -7.81, -2.03, p = 0.001), and low-density lipoproteins (WMD = -5.65 mg dL-1; 95% CI: -8.75, -2.55, p < 0.001); however it did not have a significant effect on high-density lipoprotein (WMD = -0.21 mg dL-1; 95% CI: -1.26, 0.84, p = 0.697) levels. Meta-regression analysis indicated a linear relationship between the dose of almond and change in TG (P = 0.021). This meta-analysis concludes that almond intake can significantly reduce lipid parameters. To draw straightforward conclusions regarding generalized recommendations for almond intake for improving lipid profile, there is a need for more well-controlled trials exclusively targeting patients with dyslipidaemia.

The Effects of Magnesium Supplementation on Lipid Profile Among Type 2 Diabetes Patients: a Systematic Review and Meta-analysis of Randomized Controlled Trials

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to assess the effects of magnesium (Mg) supplementation on the lipid profile in type 2 diabetes (T2DM) patients. Web of Science, Scopus, PubMed, and Embase databases were searched to infinity until 30 January 2020. Weighted mean differences (WMD) were pooled using a random-effects model. Heterogeneity, sensitivity analysis, and publication bias were reported using standard methods. The pooled analysis of 12 randomized controlled trial s indicated that Mg administration led to significant reduction of serum low-density lipoprotein (LDL) levels (p = 0.006). However, our results revealed that Mg supplementation did not have any effect on triglycerides (TG), total cholesterol (TC), and high-density lipoprotein (HDL) serum concentrations among T2DM patients in comparison with the control group. Subgroup analysis based on duration of study suggested that more than 12 weeks of Mg supplementation significantly decreased the serum TC levels (p = 0.002). Subgroup analysis comparing the dose of intervention indicated that Mg supplementation less than 300 mg significantly decreased the serum LDL concentrations (p < 0.001), while more than 300 mg of Mg supplementation significantly increased the serum HDL levels (p = 0.026). In a subgroup analysis comparing the type of intervention, it displayed that inorganic Mg supplementation decreased the LDL (p < 0.001) and TC (p = 0.003) levels, while organic Mg supplementation showed no difference. Mg supplementation has a beneficial effect on lowering LDL level in T2DM patients. However, we have to note that any research performed so far is not sufficient for making robust guidelines to use Mg supplementation in clinical practice.

Blueberry and cardiovascular disease risk factors: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Cardiovascular disease (CVD) remains an important cause of mortality and morbidity that can be prevented by the consumption of healthy foods. These include blueberry, a dark coloured berry containing extremely high amounts of functional ingredients. We therefore examined the extent to which supplementation with blueberry effects on CVD risk indices.

METHODS

We searched the ISI Web of Science, Scopus, PubMed and Cochrane Library on March 2020 and checked reference lists from primary studies and review articles for any additional studies. No language restrictions were applied. All randomized and controlled clinical trials (RCTs) using blueberry supplements to modify CVD risk factors were included in our analysis.

RESULTS

Mean Difference (MD) was pooled using a random effects model and 11 studies were included in the final analysis. Pooled effect size showed that supplementation with blueberry had a small insignificant effect in reducing plasma triglycerides (MD = -0.27 mmol/l; 95 % CI: -0.57, 0.17, p = 0.06). Although current study found no differences between blueberry and control groups for any other outcomes, subgroup analysis suggested a favourable impact of blueberry on reducing body weight. Significant weight loss was indicated from studies longer with a follow up of more than 6 weeks or with blueberry powder or freeze-dried blueberry.

CONCLUSION

Current evidence is insufficient to show a benefit of blueberry supplements in modifying CVD risk factors across a variety of adult populations. Robust data and larger studies are required to assess potential effects.