Resveratrol supplements may impair body's response to exercise

Several studies have hailed resveratrol - a compound found in red grapes - for its health benefits, so much so that it is now available in the form of supplements. But a new study claims these supplements could reverse the benefits of exercise.

Resveratrol supplements may impair the benefits of exercise rather than enhance them, say researchers.

The research team, at the School of Kinesiology and Health Studies at Queen's University in Canada, publish their findings in the journal Applied Physiology, Nutrition and Metabolism.

Resveratrol is an antioxidant that belongs to a group of plant compounds called polyphenols. It is found in red grapes, red wine, blueberries and peanuts.

Past studies have suggested the compound can help treat an array of health conditions, including acne,heart disease and cancer. But aside from its disease-combatting capabilities, previous research has applauded resveratrol for its exercise-enhancing effects. 

A 2012 study published in The Journal of Physiology, for example, claimed the compound improved skeletal muscle strength and cardiac function of mice during exercise.

But some studies have opposed such findings. In 2013, researchers from the University of Copenhagen in Denmark suggested that resveratrol could counteract the benefits of cardiovascular exercise in older men.

In this latest study, the research team set out to investigate the effects of resveratrol supplements - which they say are often marketed as "exercise mimics" - during high-intensity exercise.

Resveratrol supplementation 'does not augment training'

The team recruited 16 men who, at study baseline, engaged in up to 3 hours of aerobic exercise each week.

For the study, the men were required to increase their exercise levels and carry out high-intensity interval training three times a week for 4 weeks. In addition, the men were randomized to receive either a placebo or a 150-mg dose of resveratrol each day.

The study was double-blind, meaning both the participants and researchers were unaware of the supplementation each participant received.

The team found that after 4 weeks, the physical fitness of the men who received resveratrol supplementation did not improve. However, those who received the placebo saw some benefits associated with physical activity, such as an increase in SOD2 gene expression - associated with heart protection during exercise.

Commenting on these findings:

"The results we saw suggest that concurrent exercise training and resveratrol supplementation may alter the body's normal training response induced by low-volume high-intensity interval training.

The data set we recorded during this study clearly demonstrates that resveratrol supplementation doesn't augment training, but may impair the effect it has on the body."

The researchers add that their findings question whether resveratrol is effective as an exercise-enhancing supplement and say that further research into the association is warranted.

Earlier this year, another team of researchers claimed that taking resveratrol supplements during pregnancy may cause pancreatic problems for the fetus.