Lately, I've been on a grape kick. I'm surprised at how many varieties are available. What are their best points, nutrition-wise?
Grapes can't be beat for packing sugary sweet flavor with few calories. Although there are thousands of varieties grown throughout the world, they are usually classified in two broad categories: European and American. Both categories consist of grapes in a variety of colors, both seeded and seedless, and grown for both snacking (table grapes) and for wine.
The European type encompasses the vast majority of grapes you see in the grocery store, including the light-green Thompson seedless -- the most popular grape in America (as well as the most popular for making raisins). According to the National Nutrient Database, a cup of the European-type seedless grape has just over 100 calories, is a great source of vitamins C and K, and offers a significant amount of copper and potassium.
Grapes of the American type include the Concord, a seeded variety that's native to North America. This type is also called "slip-skin," because, compared with the European style grape, the skin just loosely adheres to the grape's flesh. You'll notice the difference when you bite into an American-style grape -- it feels a bit more wobbly in your mouth than the firmer European type does.
According to the National Nutrient Database, one cup of a seeded variety of the American type has just 60 calories and is a good source of vitamin K and manganese.
But the health benefits likely don't stop with vitamins and minerals. Grapes contain substances called polyphenols, including resveratrol and quercetin. Research suggests that these substances may help reduce the risk of blood clots from forming, and protect our arteries from the damaging effects of LDL (the "bad") cholesterol.
In addition, scientists believe resveratrol may keep the heart healthy and flexible even in the face of high blood pressure or heart failure. Those conditions can spur a series of reactions that lead to the stiffening of heart muscle, making the heart work harder to pump blood. Resveratrol, at least in the lab, appears to directly protect the heart from such reactions.
Scientists are also uncovering other possible health benefits of grapes. For example, in a study in the May 2007 Journal of Nutrition, mice fed a diet that included freeze-dried grape powder reduced inflammation associated with the development of type I diabetes.
There's still a bunch to learn about the health benefits of grapes, as well as other whole foods. And that's one reason why a balanced diet, which includes a wide variety of fruits and vegetables, is so important.
Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or firstname.lastname@example.org.
Editor: This column was reviewed by Josh Bomser, assistant professor of human nutrition in the College of Human Ecology, and Joe Scheerens, associate professor of horticulture and crop science. Both are researchers with the Ohio Agricultural Research and Development Center.