Researchers Challenge Conclusion that Resveratrol Lessens the Benefit of Exercise

In the current issue of the Journal of Physiology, a pair of researchers concluded that a recent study that showed a popular nutritional supplement could actually lessen the benefits of exercise may actually be incorrect.

  • Share on TwitterShare on FacebookShare on Google+Share on LinkedInEmail a friendRepost This

San Antonio, TX (PRWEB) October 30, 2013

A study conducted at the University of Copenhagen and published online in July in the Journal of Physiology, gained international attention when it suggested that Resveratrol, a nutritional supplement widely regarded as the molecule responsible for the health benefits of red wine, instead could actually cause harm by undoing the effects of exercise and increasing the risk of heart disease. The study was reported on in multiple press articles, but its validity is now being questioned.

On October 15, the journal published a letter from two researchers that strongly challenged the study. Their analysis suggests that the conclusions were unfounded and that no definitive conclusions can be drawn. Other studies have shown that Resveratrol may also have positive benefits for diabetes and heart disease. Blanchard states, “It’s a great example of how the scientific process continues after a study is published, and it’s a great thing when more researchers can openly discuss the implications a study.”

The original Copenhagen study declared itself to be the “first to demonstrate negative effects of Resveratrol on [exercise] training-induced improvements in cardiovascular health parameters in humans.” The study went so far as to state that “Resveratrol supplementation was found to reduce the positive effect of exercise training on blood pressure, blood cholesterol and maximal oxygen uptake and did not affect the retardation of atherosclerosis.” The recent letter strongly challenges these claims.

Upon reviewing the study other researchers found that the differences were too small to support such a surprising conclusion and that some of the study’s own data actually contradicts such negative findings. Private researcher, Otis Blanchard, and High Point University professor Dr. James Smoliga, state in their letter to the editor, “Importantly, there were no post-training differences between groups for most of these, and it is not appropriate to interpret such results as statistical differences between groups.“ Their analysis showed that the total reduction was too slight to be mathematically certain, and that there was also no clinically meaningful difference between the subjects treated with Resveratrol and those treated with a placebo.

According to Smoliga, there were other issues with the study. “There is a typical series of tests doctors use to diagnose and monitor atherosclerosis. This particular study did not use any of those procedures, and therefore would not be able to make any conclusions about atherosclerosis. The individuals studied did not have atherosclerosis in the first place, so it is impossible to reverse a medical condition that somebody does not have.” Earlier this year, Smoliga authored an article in the journal Aging which explained how research studies are often designed in such a way that they are unlikely to accurately analyze the effects of natural supplements in healthy people. Smoliga added, “this really emphasizes the need for researchers to critically interpret studies and actively speak with the mainstream media, so that the public isn't constantly confused by apparently conflicting results from scientific studies.”

Citations:

Lasse Gliemann, Jakob Friis Schmidt, Jesper Olesen, Rasmus Sjørup Biensø, Sebastian Louis Peronard, Simon Udsen Grandjean, Stefan Peter Mortensen, Michael Nyberg, Jens Bangsbo, Henriette Pilegaard, and Ylva Hellsten. Resveratrol Blunts the Positive Effects of Exercise Training on Cardiovascular Health in Aged Men. JPHYSIOL, 2013/258061

James M. Smoliga and Otis L. Blanchard. Recent data do not provide evidence that resveratrol causes ‘mainly negative’ or ‘adverse’ effects on exercise training in humans. JPHYSIOL, 2013/262956


Contact