New Study Adds to Data on Grape Juice Antioxidants

Research presented at the American College of Cardiology's 48th Annual Scientific Session in New Orleans suggests that drinking purple grape juice may delay the oxidation of low-density lipoprotein cholesterol among people with coronary artery disease—even among those already taking vitamin E.

"We know that the oxidation of LDL is a key contributor to the development of atherosclerosis—which is the build up of plaque in the coronary artery," said John Folts, Ph.D., director of the Coronary Thrombosis Research Laboratory at the University of Wisconsin School of Medicine and co-author of the study. "Anything we can do to delay the onset of that oxidation should be beneficial. One reason why organizations like the American Heart Association urge people to eat diets rich in fruits and vegetables is for the antioxidant benefits these foods provide. Many people take the antioxidant vitamin E for the same reason."

The study included 14 people with stable coronary artery disease, 11 of whom were taking vitamin E. The patients all consumed purple grape juice (7 to 10 ml/kg of body weight per day) for 14 days. Researchers drew blood samples and measured LDL oxidation lag time at the beginning of the study and at its conclusion. Lag time measurement is a commonly used method for determining how long it takes for cholesterol to oxidize when exposed to certain oxidant chemicals. The longer the lag time, the slower the onset of oxidation.

Before drinking the juice, the average lag time was 87 minutes (more or less 29 minutes). After drinking the juice, lag time was 117 minutes (more or less 23 minutes). In looking at just those patients who were consuming vitamin E (400IU/day), the initial lag time was 86 minutes (more or less 33 minutes); after drinking the juice it was 121 minutes (more or less 24 minutes).

Similar research is currently being conducted on healthy subjects. Folts notes that the results, although preliminary, are significant. While the number of subjects was relatively small, they served as their own controls, and a significant antioxidant effect was observed in each subject.

"When we combine this new data with what we already know about purple grape juice's ability to reduce platelet activity and increase nitric oxide production, there appears to be a growing body of research suggesting that drinking purple grape juice can contribute to healthy cardiovascular function in several ways," said Folts.