Too many antioxidants? Resveratrol in pill form blocks many cardiovascular benefits of exercise
According to research published July 22 in The Journal of Physiology, high dose resveratrol supplements might block many of the cardiovascular benefits of exercise in older men.
The authors from the University of Copenhagen state that resveratrol (found naturally in red wine) has received widespread attention as a possible anti-aging compound and is now widely available as a dietary supplement; much has been made of its role in explaining the cardiovascular health benefits of red wine, and other foods. However, this research suggests that taking antioxidants in supplement rather than natural form may actually counteract many of the health benefits of exercise, including reduced blood pressure and cholesterol.
The study followed 27 healthy, physically inactive men around 65 years old for 8 weeks. During the 8 weeks all of the men performed high-intensity exercise training and half of the group received 250 mg of resveratrol daily, whereas the other group received a placebo pill (a pill containing no active ingredient). The study design was double-blinded, thus neither the subjects nor the investigators knew which participant that received either resveratrol or placebo.
It was found that exercise training was highly effective in improving cardiovascular health parameters, but resveratrol supplementation attenuated the positive effects of training on several parameters including blood pressure, plasma lipid concentrations and maximal oxygen uptake.
Ylva Hellsten, the leader of the project, said: “We were surprised to find that resveratrol supplementation in aged men blunts the positive effects of exercise training on cardiovascular health parameters, in part because our results contradict findings in animal studies… It should be noted that the quantities of resveratrol given in our research study are much higher than what could be obtained by intake of natural foods.”
The authors say that what is emerging is a new view that high dose antioxidants are not a fix for everything, and that some degree of oxidant stress may be necessary for the body to work correctly. This pivotal study suggests that reactive oxygen species, generally thought of as causing aging and disease, may be a necessary signal that causes healthy adaptations in response to stresses like exercise. So too much of a good thing (like antioxidants in the diet) may actually be detrimental to our health.
Source: Lasse Gliemann, JF Schmidt, J Olesen, RS Biensø, SLPeronard, SU Grandjean, SP Mortensen, M Nyberg, J Bangsbo, H Pilegaard,, Y Hellsten. Resveratrol Blunts the Positive Effects of Exercise Training on Cardiovascular Health in Aged Men. JPHYSIOL, 2013/258061