Flavonoids that are found in fruit, vegetables, chocolate, tea, wine, and grape juice reduce cellular oxidative stress and are associated with a reduced risk of cancer and heart disease. Concord grape juice is a rich source of flavonoids, but it has not been compared to antioxidant supplements in terms of its efficacy in reducing oxidative stress.

In an article in the American Journal of Clinical Nutrition, O'Byrne et al. compared the effects of Concord grape juice (CGJ) and antioxidant supplements in a group of healthy subjects, and found that CGJ is a potent, long-lasting antioxidant that compares favorably to supplements in its action and perhaps has unique properties that supplements do not.

The 32 participants, who were all healthy and averaged 28 years old, were assigned to receive 400 IU of á-tocopherol (an antioxidant supplement), or 10 mL per day of 100% CGJ over a 2-week period. Prior to and throughout the study, the subjects were on a flavonoid-restricted diet to ensure that the primary source of flavonoids in their diets was either from the grape juice or the supplements, and fasting blood samples were collected before, during, and after the study period.

Both CJG and antioxidant supplements provided significant antioxidant protection to serum, plasma proteins, and low-density lipoproteins (LDL). A unique finding was that CGJ has a previously unknown antioxidant capability of reducing the concentration of oxidized protein in the blood by 20%, which the supplements did not.

The authors suggest that future studies should investigate the long-term antioxidant effects of CJD in combination with a well-defined diet. CGJ is a popular beverage that could provide an everyday method for prevention of chronic disease in all age groups.

SOURCE:
American Journal of Clinical Nutrition, December 2002