AJCN.org – Two new studies on resveratrol and red wine point to their possible benefits for body fat metabolism and vascular endothelial function.

The “French Paradox” refers to relatively low cardiovascular disease prevalence in France despite high dietary saturated fat consumption and cigarette smoking. Among factors thought to provide cardioprotective benefits to the French is red wine because it contains myriad substances with potentially antiatherogenic effects, including a variety of polyphenols. For instance, it contains resveratrol, an antioxidant that can decrease inflammation and is purported to have “anti-aging” benefits. However, much more research is needed on resveratrol to determine whether this compound can help ward off or even treat heart disease. Two articles published in the July 2010 issue of The American Journal of Clinical Nutrition provide new insight on this topic, and an accompanying editorial offers commentary as to the evolution of these types of studies and the need for additional controlled clinical trials.

In the first study, Martin Wabitsch and Pamela Fischer-Posovszky and colleagues studied the possibility that resveratrol might decrease risk of obesity (and thus, cardiovascular disease) by 1) influencing whether “preadipocytes” (immature fat cells) are prompted to become full-fledged adipocytes (fat cells) and 2) affecting fat synthesis and metabolism in adipocytes. Specifically, they studied the effects of resveratrol on Sirt 1 (sirtuin 1), a protein that some research has found to be cardioprotective. In the second study, Saher Hamed and coworkers from the Israel Institute of Technology studied 15 healthy adult volunteers (mean age: 29 y) who agreed to consume 250 mL (8.8 oz or 1.75 servings) of red wine daily for 21 days. At the beginning and end of the study, blood samples were taken and tested for a variety of measures of vascular endothelial cell function (reflecting blood vessel integrity).

Results from the in vitro study by Wabitsch and colleagues showed that resveratrol can inhibit growth and differentiation of preadipocytes and that this effect is likely due to Sirt 1. In mature adipocytes, resveratrol stimulated glucose uptake, decreased lipid synthesis, and suppressed the production of interleukin-6 and interleukin-8 (inflammatory compounds). Data from the human intervention trial supported a beneficial effect of wine consumption on vascular function. Specifically, Hamed’s study showed that drinking a moderate amount of wine daily increased the number and migration of endothelial progenitor cells as well as their production of nitric oxide, a compound important for a healthy vascular response. This effect was even more pronounced when the cells were “stressed” with glucose.

Together these results extend what we know about how resveratrol influences physiologic function and provide additional evidence that moderate red wine consumption can be beneficial. In the accompanying editorial, Evi Mercken and Rafael de Cabo elaborate on the multiple (and expanding) physiologic endpoints that appear to be influenced by resveratrol. They also pose numerous lingering questions related to resveratrol’s mechanisms and stress the importance of additional intervention trials.

References:

Fischer-Posovszky P, Kukulus V, Tews D, et al. Resveratrol regulates human adipocyte number and function in a Sirt1-dependent manner. American Journal of Clinical Nutrition 2010;92:5–15.

Hamed S, Alshiek J, Aharon A, Brenner B, Roguin A. Red wine consumption improves in vitro migration of endothelial progenitor cells in young, healthy individuals. American Journal of Clinical Nutrition 2010;92:161–9.

Mercken EM, de Cabo R. A toast to your health, one drink at a time. American Journal of Clinical Nutrition 2010;92:1–2.