Could Red Wine Supplement Block Exercise Benefits?
In small study, resveratrol undermined gains in blood pressure, cholesterol and aerobic fitness
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Relatively high doses of antioxidants have not been effective in a number of larger clinical trials on a number of topics, said Dr. Michael Joyner, a physiologist at the Mayo Clinic in Rochester, Minn.
"Some people think you need at least a bit of oxidative stress to trigger or stimulate exercise training responses," Joyner said. "The same thing is true for inflammation. Too much is bad, but some might be required for normal physiological signaling."
In short, free radicals, which are thought to contribute to inflammation, aging and disease, may actually be necessary to trigger the body's healthy responses to exercise. So when it comes to antioxidants, how much is too much? Study co-author Gliemann said that more research is needed to answer that question.
"To test that, we would have to make a dose-response study," he said. "But given that the amount of resveratrol we gave in the present study equals several bottles of red wine daily, we can conclude that 250 mg resveratrol as a supplement is not a good thing when training."
Joyner said a healthy diet might be a better option than taking antioxidant supplements such as resveratrol. "There is some thinking that it is best to get antioxidants via a diet rich in fruits, vegetables and healthy oils," he said.
Although previous studies suggested that resveratrol may improve the benefits of exercise on heart health and help protect against diabetes, these findings were reported in animals, not people.
A separate 2012 study conducted by researchers at the Washington University School of Medicine and published in the journal Cell Metabolism also found that resveratrol supplementation does not have metabolic benefits in relatively healthy, middle-aged women.