Grapes

Grapes of all colors are chock-full of antioxidants and a myriad of other phytonutrients. Some that have been identified as possible cardioprotectors are flavonoids such as resveratrol and quercetin, procyanidins, tannins, and saponins. But keep in mind that the grapes you find in the grocery store aren’t necessarily as hearty as those used for making wine and grape juice. And unless you eat the seeds along with the grapes, you won’t get the nutrients sequestered there. Wine and grape juice contain substances leached from seeds, which are crushed during the pressing process.
Grapes offer a small amount of fiber, which is good for the heart and digestive system, something neither wine nor grape juice deliver. It takes about 8 to 10 ounces of grapes (nearly two cups worth) to make a glass of wine or grape juice.
Grape juice (not to be confused with grape-flavored “drinks,” which are mostly sugar water) delivers slightly more antioxidants and other phytonutrients than its equivalent in grapes. Red wine, like grape juice, is a rich brew of antioxidants and phytonutrients. And it contains alcohol, something not found in either grapes or grape juice.
What is known about the ability of different forms of the grape to protect the heart? A few small studies have shown that red and purple grape juices reduce the stickiness of platelets, a key player in blood clotting. Grape juice also slightly raises HDL, reduces inflammation, and improves the ability of blood vessels to relax. (The “dose” in these studies was two 8-ounce glasses of purple grape juice a day.)
So far, though, there is no evidence that drinking grape juice has an effect on the things we really care about, like fewer heart attacks or longer lives. University of Connecticut researchers have shown that mice fed just the flesh of grapes, without the skin, are just as protected against experimentally induced heart attack damage as mice fed grape skins. Whether that translates to humans remains to be seen. In fact, there is reason to believe that the amount of flavonoids in one to two glasses of grape juice is far short of what would be needed to have important health benefits. Also, don’t forget that grapes are high in natural sugars, which are fine in small to moderate amounts. But consuming large amounts, which is easy to do in the form of juice, could well increase your weight, not to mention your risk of type 2 diabetes and heart disease.
In contrast, there is solid evidence that alcohol in moderation offers some protection against heart disease and ischemic (clot-caused) stroke and that it probably reduces premature deaths in healthy people as well as those with diabetes, high blood pressure, and other chronic conditions. Although red wine initially looked to be special in this regard, any alcohol-containing beverage — red wine, white wine, beer, cordials, and spirits such as gin or Scotch whisky — offers similar protection. Alcohol may do this by raising HDL (good) cholesterol, hindering the formation of artery-blocking blood clots, easing inflammation, or by some other as-yet-undiscovered route. The key is moderate drinking. This means no more than two drinks a day for men and one a day for women.
There are better ways than grapes or alcohol to protect your heart. You know the list: exercising, following a healthful diet, not smoking, maintaining a healthy weight, easing stress.
If you enjoy wine, then savor it. If the rich flavor of grape juice gets your engine running in the morning, bottoms up with a small glass. If you love snacking on grapes, crunch away. These are beverages and foods to enjoy, not heart-protecting medicines to take on some arbitrary schedule.
— Walter C. Willett, M.D.
Harvard School of Public Health