Is a glass of Cabernet Sauvignon or Pinot Noir your guilty pleasure after a grueling day's work? If your goal is a healthy, fit body, a red-wine habit is not the worst vice in the world.

A series of scientific studies have established that certain compounds in the crimson-colored varietals may actually benefit your health. But how beneficial is it, and how much (or how little) should one drink to get the full health effect?

"It's thought that red wine, despite the alcohol content, also has helpful properties, like resveratrol and other polyphenols," says Barbara Shukitt-Hale, a research psychologist at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston.

Polyphenols are chemical compounds found in the skin of grapes and other plants. These compounds act as "antioxidants" -- the vitamins, minerals and enzymes in foods that protect the cells in your body from damage caused by the normal process of metabolism and ward off chronic disease. Resveratrol is a type of polyphenol found in red wine.

You could say that each serving that you have of a fruit or a vegetable — or perhaps a glass of wine — is beneficial, Shukitt-Hale reasons, as long as you don't forget that wine is alcohol, and you need to drink responsibly.

"You don't want to have seven glasses of red wine a day instead of seven servings of fruits and vegetables," she cautions.

One of most widely documented benefits of red wine is heart health. A pivotal study published several years ago in journal Nature found that red wine inhibited the synthesis of a protein called endothelin-1 that can lead to the development of atherosclerosis, a build-up of fatty material along the artery walls.