Resveratrol, the compound in red wine potentially responsible for its beneficial cardiovascular effects, may also benefit patients with prediabetes, researchers say.... In a small and preliminary study, older patients with impaired fasting glucose taking a resveratrol supplement had improvements in postprandial glucose and insulin resistance, according to Jill P. Crandall, MD, of Albert Einstein College of Medicine in Bronx, N.Y., and colleagues.