The Effects of Red Wine Polyphenols on Microvascular Dysfunction

Rationale:

Epidemiological studies have shown that consumption of alcoholic beverages, red wine in particular, is associated with less cardiovascular mortality. In addition, there are reported beneficial effects of red wine on components of the metabolic syndrome, arguably the most menacing cardiometabolic condition facing us due to the unfolding obesity epidemic. Beneficial effects have also been reported with other polyphenol-rich food stuff, such as cocoa and green tea and points to a beneficial effect which does not seem to be dependent on the alcohol content of red wine. Experimental studies with mixed or separate Red Wine Polyphenols (RWPs) (i.e. without alcohol) have shown beneficial effects on cardiometabolic parameters associated with obesity. Most research has focused on resveratrol, a specific polyphenol components which is quite specific to red wine and has, at least in animal studies, beneficial effects on insulin sensitivity, insulin secretion, and endothelial function. Moreover, RWPs have shown to improve endothelial NO-mediated relaxation using the same PI3-kinase/Akt pathway as does insulin. However, data in humans are remarkably scarce

Objective:

To study effects of RWPs on insulin sensitivity, beta-cell function, microvascular function (skin, muscle and cardiac), blood pressure, insulin-mediated microvascular responsiveness.

Study design:

Randomized controlled trial (double blind).

Study population:

Obese (BMI >30); n=30, men or women, aged 18-60 years.

Intervention:

Mixed RWP 600mg/day or matching placebo for a total duration of 8 weeks.