According to a newly published USDA database, purple grape juice made from Concord grapes tested higher in total proanthocyanidins--natural plant compounds that function as antioxidants and may contribute to good health in a variety of ways -- than any of the juices or beverages it tested on a per serving basis, including red wine, tea, cranberry juice cocktail and apple juice. The new database is part of an effort to quantify some of the micronutrient status of the foods Americans consume.
"These plant compounds are of great interest because of their potent antioxidant capacity and possible protective effects on human health. Flavonoids in fruits, vegetables and juices appear to play a significant role in cancer and heart disease health benefits, and proanthocyanidins account for a significant portion of the total flavonoids ingested by Americans," says Ronald L. Prior, Ph.D., nutritionist, USDA Agricultural Research Service, Arkansas Children's Nutrition Center. "Up until now, however, it has been difficult to compare the relative concentrations of these micronutrients in common foods. This database is an important step in that direction."
According to the database, grape juice topped the beverage list by containing 124 milligrams of proanthocyanidins per 8 ounce serving. Compared to grape juice, red wine had 91 milligrams/5 ounce serving, cranberry juice cocktail had 55 milligrams/8 ounce serving, brewed tea had 32 milligrams/8 ounce serving and apple juice had 30 milligrams/8 ounce serving. Beer and chocolate milk trailed, each with about 7 milligrams/serving (12 and 8 ounce servings, respectively).
"This is not surprising," adds Prior. "In a previous study we published, we measured the antioxidant capacity of several commercial juices and found Concord grape juice to be more than two times higher than orange, apple, grapefruit or tomato juice."
Another researcher who has studied the cardiovascular health benefits of Concord grape juice, John D. Folts, Ph.D., University of Wisconsin Medical School-Madison, notes, "These findings underscore what we know already about the potential benefits of Concord grape juice. In preliminary studies, it reduced the tendency of blood platelets to aggregate, slowed the oxidation of LDL cholesterol, enhanced the flexibility of the arteries and reduced blood pressure."
While the authors recognize the interest in proanthocyanidins because of their potent antioxidant and potential protective effect, choosing foods high in these compounds is only one part of a healthy diet.