A glass of purple grape juice is
more fruitful than you might have imagined. According to preliminary research
by a University of Scranton professor, the fruit of the grapevine appears to
bear powerful antioxidant qualities that may improve the body's healthy
The study, published in the February 2001 issue of Journal of Medicinal
Food, used novel and extremely accurate methodology to research the
antioxidant qualities of grape juice. Antioxidants have been shown to prevent
the oxidation of cholesterol, especially the bad cholesterol, low-density
lipoprotein (LDL). High cholesterol is, of course, a scientifically
documented risk factor for heart disease. Recently LDL oxidation has been
hypothesized as the beginning of the atherosclerosis process that starts in
childhood. In short, your "pipes" begin to rust at an early age.
The study led by Joe A. Vinson, Ph.D., professor of chemistry at The
University of Scranton, analyzed lab tests and the results of human subjects
drinking grape juice and orange juice.
"The take-away message from our study is that people who are looking to
promote the body's healthy cardiovascular function through increased
antioxidant consumption might prefer a glass of purple grape juice in the
morning," said Dr. Vinson. "In our research, which involved two different test
tube models, we saw dramatically superior antioxidant performance by grape
juice. We added grape juice to either human plasma or human LDL and then
oxidized it. Grape juice was very effective, but orange juice had no
In the human testing conducted by Dr. Vinson, 16 participants were asked
to drink either two glasses of grape juice or two glasses of orange juice
daily over a period of one week. The study then used blood samples to measure
the LDLs' lag time among participants.
In lag time measurement -- a well-accepted method of determining
antioxidant effect -- LDL is isolated and exposed to an oxidizing agent. The
duration of time between exposure to oxidation and actual oxidation is called
lag time. The longer it takes for LDL to oxidize, the less likely it is to
contribute to the process where fatty substances like cholesterol cause damage
to the arteries.
Subjects consuming purple grape juice showed an increase in lag time of
27 percent. Subjects drinking orange juice showed no change in lag time.
Co-authors of the study led by Dr. Vinson were University of Scranton
students Jihong Yang, Xiquan Liang and research assistant John Proch. Ms. Yang
and Mr. Liang, both from China, participated in the research project as
chemistry graduate students. Ms. Yang is now a senior chemist at Lancaster
Labs, Lancaster, Pa. Mr. Liang is continuing his studies at Sloan-Kettering
Institute in New York, N.Y. Mr. Proch is a research assistant at the
Commenting on her participation in the study, Ms. Yang said, "I worked in
research in China for six years before coming to The University of Scranton.
By participating in Dr. Vinson's experiment, I learned the way in which
research was done the United States. This gave me the experience I need to do
my job; I also learned what is beneficial to human beings. When I visit
relatives in China, I always introduce them to what I learned about
Those who follow the antioxidant qualities of various foods may have
already heard rumblings about this research through the grapevine. According
to Dr. Vinson, the study's conclusions build upon and support previous
research, including a 1996 USDA study that showed that the total antioxidant
capacity of purple grape juice is more than three times that of orange,
grapefruit, tomato or apple juice.
"People drink fruit juice for many reasons," concluded Dr. Vinson. "Orange
juice, for example, is an excellent source of Vitamin C, folate and potassium
-- nutrients many people may consume in sufficient quantity in their diets
otherwise. But for people looking for dietary approaches to increase
consumption of natural antioxidants that may help reduce the risk of heart
disease, purple grape juice appears unique in its potential ability to provide
a beneficial effect to a variety of cardiovascular functions."