(CBS) Several studies have lauded the anti-aging effects of resveratrol, an antioxidant found in grape-based products like red wine. A new study, however, suggests the compound could have some drawbacks.
Recent research has shown that consuming a large quantity of resveratrol in supplement form -- about the equivalent of 700 bottles of red wine -- may improve balance in elderly mice. A September 2012 study in Circulation Research showed that drinking non-alcoholic, resveratrol-rich red wine for four weeks may lower blood pressure.
One 2011 study even referred to red wine as "exercise in a bottle," after reservatrol protected against muscle loss in sedentary rats.
However, a new study of older men suggests that reservatrol may block the health benefits gained from exercise.
"We were surprised to find that resveratrol supplementation in aged men blunts the positive effects of exercise training on cardiovascular health...in part because our results contradict findings in animal studies," lead researcher Ylva Hellsten, a professor with the University of Copenhagen in Denmark, said to the Free Press Journal.
Researchers looked at 27 healthy men aged 65 or older who were physically inactive. They were put through an intensive eight-week regimen which including CrossFit and circuit training exercises.
The men were randomized to receive either 250 milligrams of a resveratrol supplement or a placebo.
Exercise was shown to improve cardiovascular health, but the resveratrol supplement seemed to block the effects.
At the end of the program, the placebo group had a 45 percent greater increase in maximal oxygen uptake than those who were in the resveratrol group. Maximal oxygen uptake is a measure of how much oxygen gets delivered to muscles during exercise. The placebo group also experienced a decrease in their blood pressure and levels of the blood compound prostacyclin, a fatty lipid that stops platelets (which are responsible for forming blood clots) from being activated and prevents blood vessels from widening.
High maximal oxygen update and low levels of blood pressure and prostacyclin are signs of good cardiovascular health.
The resveratrol group did not experience any positive health benefits regarding their cholesterol levels and triglycerides, while the placebo group did.
"These findings indicate that, whereas exercise training effectively improves several cardiovascular health parameters in aged men, concomitant resveratrol supplementation blunts most of these effects," the authors wrote.
The study, which was published on July 22 in The Journal of Physiology, was only conducted on a small group, so more study is needed.
It's also important to note that the participants took a supplement, and the amount of resveratrol they took was much higher than what would be consumed under normal dietary practices. The Harvard Medical School recommends getting a much lower resveratrol dose from natural sources like red grapes, blueberries, pistachios or red wine. Furthermore, experts warn the supplements don't always contain the amount of resveratrol they say they do.
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