If someone lifts a glass of wine and toasts your health, take it seriously. Mounting evidence shows that red wine and purple grape juice may protect against a range of maladies, such as cancer, stroke, cardiovascular and Alzheimer's diseases, and more. Much of the credit goes to resveratrol, an antioxidant produced by grape skin to defend against fungus and disease.

“It's a ‘desert-island nutrient’ — I wouldn't want to be without it,” says Fred Pescatore, MD, MPH, an integrative-medicine specialist in New York City, who recommends taking 50-100 mg in supplement form three times daily. Although this is significantly more than the 2 mg of resveratrol found in a glass of red wine, don't be concerned about the high dose: Resveratrol accumulates in your body's tissues with no toxicity or side effects, says Dianzheng Zhang, PhD, a resveratrol researcher and assistant professor at Philadelphia College of Osteopathic Medicine. Still, consider enhancing your diet with resveratrol-rich foods — such as grapes, blueberries, raspberries, peanuts, dark chocolate, and cocoa — which contain a host of other phytochemicals and nutrients, he adds.