The effect of grapes/grape products on glycemic response: A systematic review and meta‐analysis of randomized controlled trials

Abstract

The aim of this study was to perform a systematic review and meta‐analysis of randomized clinical trials (RCTs) to examine the effect of grapes/grape products supplementation on glycemic indices in adults. Our systematic search to find relevant RCTs was performed up to February 2020 using PubMed, Scopus, ISI Web of Science, Cochrane Library, and Google Scholar. Based on the heterogeneity between included studies, a random effects or a fixed model was applied in the meta‐analysis, and results were expressed as weighted mean differences (WMD) with 95% confidence intervals (CI). Twenty‐nine clinical trials (1,297 participants) fulfilled the eligibility criteria of the present meta‐analysis. Overall, the grapes/grape products supplementation significantly reduced homeostatic model assessment of insulin resistance (HOMA‐IR) (WMD: −0.54, 95% CI: −0.91, −0.17, p = . 004) but did not affect fasting insulin levels (WMD: −0.90 μIU/ml, 95% CI: −1.04, 2.84, p = .362) and hemoglobin A1C (Hb1Ac) percentage (WMD: 0.00%, 95% CI: −0.10, 0.11, p = . 916) in the main analyses. In addition, changes to fasting blood glucose (FBG) levels were in favor of the control group (WMD: 1.19 mg/dl, 95% CI: 0.05, 2.34, p = .041). We found that giving grapes/grape products to adults might have beneficial effects on the HOMA‐IR. Further, large‐scale RCTs with longer duration are required to confirm these results.

Effect of mulberry leaf or mulberry leaf extract on glycemic traits: a systematic review and meta-analysis

“…56 Several therapeutic strategies such as natural extracts have been developed with the objective of improving the glycemic response. 57 There has been interest in MLE in the scientific community, and ML and MLE are used for hypoglycemia, obesity, and T2DM 39 because they are rich in phenolics, flavonoids, and polysaccharides, especially 1-DNJ, which is a unique active ingredient in ML. 58,59…”

“…objective of improving the glycemic response. 57 There has been interest in MLE in the scientific community, and ML and MLE are used for hypoglycemia, obesity, and T2DM 39 because they are rich in phenolics, flavonoids, and polysaccharides, especially 1-DNJ, which is a unique active ingredient in ML. 58,59 To the best of our knowledge, this is the first meta-analysis to examine the effects of ML/MLE on glycemic traits.…”

Hypoglycemic effects and associated mechanisms of resveratrol and related stilbenes in diet

“…For instance, the consumption of grape powder, grape skin extract and grape seed oil successfully prevented increased fasting blood glucose and dyslipidemia in mice, and red grape pomace extract, which comes from winemaking by-products, was able to suppress postprandial hyperglycemia (PPHG). 8 These grape products are also capable of decreasing oxidative stress and inflammation and promoting cardiac health. 9 Blueberry, a "superfruit" that is commonly consumed in Western countries and has gained increasing popularity in Asia in recent years, is well-linked to several health-promoting effects.…”

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

“…There is ample evidence that certain foods and nutrients have good effects on the liver (Abbasnezhad et al, 2019; Asbaghi, Ghanbari, et al, 2020; Asbaghi, Kashkooli, et al, 2021; Asbaghi, Naeini, et al, 2021; Mousavi et al, 2021; Yousefi Rad et al, 2019). Grapes, a group of fruits with high polyphenol content, have been shown to exert several antioxidants, antiinflammatory, and anti‐diabetic properties (Asbaghi, Nazarian, et al, 2020; Ghalishourani et al, 2021; Moodi et al, 2021; Ramchandani, Chettiyar, & Pakhale, 2010), and are widely consumed around the world. The results of a meta‐analysis study including randomized controlled trials (RCTs) by Asbaghi, Nazarian, et al (2020) showed that administration of grape seed extract (GSE) significantly lowered C‐reactive protein (CRP) levels as a marker of acute phase inflammation produced by the liver.…”