Wine Information Council

The aim of this study was to investigate the effects of dietary supplementation with a nonalcoholic red wine extract (RWE), including resveratrol and polyphenols, on insulin sensitivity and Sirt1 expression in nondiabetic humans. The present study was a single-arm, open-label and prospective study.

Twelve subjects received supplementation with RWE, including 19.2 mg resveratrol and 136 mg polyphenols, daily for 8 weeks. After 8 weeks, metabolic parameters, including glucose/lipid metabolism and inflammatory markers, were evaluated. mRNA expression of Sirt1 was evaluated in isolated peripheral blood mononuclear cells (PBMNCs). Additionally, Sirt1 and phosphorylated AMP-activated kinase (p-AMPK) expression were evaluated in cultured human monocytes (THP-1 cells). Supplementation with RWE for 8 weeks decreased the homeostasis model assessment for insulin resistance (HOMA-IR), which indicates an increase in insulin sensitivity. Serum low-density lipoprotein-cholesterol (LDL-C), triglyceride (TG) and interleukin-6 (IL-6) were significantly decreased by RWE supplementation for 8 weeks. Additionally, Sirt1 mRNA expression in isolated PBMNCs was significantly increased after 8 weeks of RWE supplementation.

Moreover, the rate of increase in Sirt1 expression was positively correlated with the rate of change in HOMA-IR. The administration of RWE increased Sirt1 and p-AMPK expression in cultured THP-1 cells. Supplementation with RWE improved metabolism, such as insulin sensitivity, lipid profile and inflammation, in humans. Additionally, RWE supplementation induced an increase in Sirt1 expression in PBMNCs, which may be associated with an improvement in insulin sensitivity.

BACKGROUND: Effects of resveratrol on metabolic health have been studied in several short-term human clinical trials, with conflicting results. Next to dose, the duration of the clinical trials may explain the lack of effect in some studies, but long-term studies are still limited. OBJECTIVES: The objective of this study was to investigate the effects of 6-mo resveratrol supplementation on metabolic health outcome parameters. METHODS: Forty-one overweight men and women (BMI: 27-35 kg/m2; aged 40-70 y) completed the study. In this parallel-group, double-blind clinical trial, participants were randomized to receive either 150 mg/d of resveratrol (n = 20) or placebo (n = 21) for 6 mo. The primary outcome of the study was insulin sensitivity, using the Matsuda index. Secondary outcome measures were intrahepatic lipid (IHL) content, body composition, resting energy metabolism, blood pressure, plasma markers, physical performance, quality of life, and quality of sleep. Postintervention differences between the resveratrol and placebo arms were evaluated by ANCOVA adjusting for corresponding preintervention variables. RESULTS: Preintervention, no differences were observed between the 2 treatment arms. Insulin sensitivity was not affected after 6 mo of resveratrol treatment (adjusted mean Matsuda index: 5.18 +/- 0.35 in the resveratrol arm compared with 5.50 +/- 0.34 in the placebo arm), although there was a significant difference in postintervention glycated hemoglobin (HbA1c) between the arms (P = 0.007). The adjusted means showed that postintervention HbA1c was lower on resveratrol (35.8 +/- 0.43 mmol/mol) compared with placebo (37.6 +/- 0.44 mmol/mol). No postintervention differences were found in IHL, body composition, blood pressure, energy metabolism, physical performance, or quality of life and sleep between treatment arms. CONCLUSIONS: After 6 mo of resveratrol supplementation, insulin sensitivity was unaffected in the resveratrol arm compared with the placebo arm. Nonetheless, HbA1c was lower in overweight men and women in the resveratrol arm. This trial was registered at Clinicaltrials.gov as NCT02565979.

Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking.

Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes.

Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

Polyphenols are nonessential phytonutrients abundantly found in fruits and vegetables. A wealth of data from preclinical models and clinical trials consistently supports cardiometabolic benefits associated with dietary polyphenols in murine models and humans.

Furthermore, a growing number of studies have shown that specific classes of polyphenols, such as proanthocyanidins (PACs) and ellagitannins, as well as the stilbenoid resveratrol, can alleviate several features of the metabolic syndrome. Moreover, mounting evidence points to the gut microbiota as a key mediator of the health benefits of polyphenols.

In this review we summarize recent findings supporting the beneficial potential of polyphenols against cardiometabolic diseases, with a focus on the role of host-microbe interactions.