Ask the doctor; Do grapes and grape juice protect the heart like wine does?

Q. For the health of my heart and arteries, how does regular consumption of red wine compare with grape juice or the equivalent in grapes?

A. You are asking a question that science hasn't caught up with, especially when it comes to grape juice and grapes. Let's start by looking at what you get with each of these.

Grapes of all colors are chock-full of antioxidants and myriad 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 8-10 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 the flesh of grapes ...