Here’s why I am not surprised by the findings:
of the previous studies that have shown benefits from resveratrol have been
done in rats. Rats are not humans – a fact often lost on those humans reporting
on scientific studies and supplement makers.
the rat and the human studies have used large doses of resveratrol from
supplements – far more than we can possibly get from foods and beverages.
human studies have shown benefits - and some have not. The ones that have shown
benefits often look at “markers of inflammation” and show that resveratrol
supplements lowered these markers. One study showed that resveratrol supplements
lowered stiffness in the arteries of women. But, just lowering a marker of
something bad does not necessarily translate into improved health or a lower
chance of dying. I see this kind of data on markers of health all the time and
they are useful but we shouldn’t base our recommendations off of them. These
kinds of studies need to lead to studies that look at the outcomes that really
matter – like disease, disability, and death.
- Some human studies have shown no benefit and even harm from resveratrol supplements. One study showed that when older men were randomized to get either a 250 mg resveratrol supplement or a placebo for eight weeks during an intense exercise program, the men on the supplement did not experience the positive changes in cholesterol levels or in blood flow that the men on the placebo did. In other words, the supplements actually impaired some of the benefits of exercise rather than improving them as expected!
Beth Kitchin, PhD, RDN
Assistant Professor, Nutrition Sciences
University of Alabama at Birmingham
Semba RD, Ferrucci L, Bartali B, Urpi-Sarda M, Zamora-Ros R, Sun K, et al. Resveratrol levels and all-cause mortality in older community-dwelling adults. JAMA. 2014; published online May 12, 2014.