Drinking Purple Grape Juice Significantly Reduced Oxidation of Bad Cholesterol, According to Study
Onset of LDL oxidation delayed by more than a third, on average, even among patients taking vitamin E
New Orleans, LA, March 1, 1999
Research presented at the American College of Cardiology’s 48th Annual Scientific Session suggests that drinking purple grape juice may delay the oxidation of LDL cholesterol, the so-called "bad" 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," explains John D. 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. What is particularly interesting," adds Folts, "is that even in those people who were already taking vitamin E—which is a powerful antioxidant—we saw a similar delay in onset of LDL oxidation."
The study included fourteen people with stable coronary artery disease, eleven of whom were taking vitamin E. The patients all consumed purple grape juice (7-10 ml/kg of body weight per day) for 14 days. Blood samples were drawn and LDL oxidation lag time was measured at the beginning of the study and then again 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 (± 29 minutes). After drinking the juice, lag time was 117 minutes (± 23 minutes). In looking at just those patients who were consuming vitamin E (400IU/day), the initial lag time was 86 minutes (± 33 minutes); after drinking the juice it was 121 minutes (± 24 minutes).
The study was conducted on 11 men and 3 women with existing coronary artery disease. 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," Folts says.
The study was underwritten by the Oscar Rennenbohm Foundation, Madison, WI; the Nutricia Research Foundation, The Netherlands; and Welch Foods, Inc., A Cooperative, Concord, MA.
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