Resveratrol is the antioxidant found in red grapes, red wine, and berries that has been touted as an anti-aging miracle. It's antioxidant properties reduce inflammation, which in turn, should help reduce the risk of heart disease, some cancers, type II diabetes, and reduce cell damage that also leads to Alzheimer's and other age-related diseases. Because there have been very few studies conducted on resveratrol in humans, doctors still can't confirm any benefits, and they don't know what effects the supplements may have on people over the long term. Research in Scandinavia tested the supplement on healthy sedentary men over age 60 who participated in an 8 week high intensity training program. They were compared to a similar group of men who were given a placebo. By the end of the training period, the men taking the placebo had better oxygen capacity than those taking the resveratrol. Blood pressure, triglycerides, LDL & HDL cholesterols improved in the placebo group only. This study suggests that the antioxidant may blunt the benefits of exercise.
There seems to be no reason to take the supplement. The participants in the study took 250mg/ day. You would need to drink 113 bottles of merlot to get that much, so go ahead and have that glass of wine with dinner.
~ J. Physiol, 2013