Wine and grapes have made headlines recently because of studies showing they may help prevent cancer. Such news has led sales of both grape seed and grape skin extracts to soar, and wine taken in the name of la santé (good health) has become fashionable.
The plant chemical behind the headlines is called resveratrol. It is found in grapes and grape leaves, peanuts, mulberries, some species of eucalyptus, pine, and cypress, to name a few sources. Grape leaves are the best source of resveratrol—they are up to one hundred times richer in resveratrol than the fruits. It is believed that plants produce resveratrol to help ward off fungus.
You may already be familiar with resveratrol, because research has linked the substance and its sources, such as wine, to cardiovascular benefits. Many studies have shown that people who drink moderate amounts of wine have less heart disease than heavy drinkers and non-drinkers. This is known as the “French paradox” based on a study published in 1992 showing that the French have lower rates of coronary heart disease despite eating a fairly high-fat diet. A comparison of French and American diets shows that the French eat far less junk food and more fruits and vegetables, don’t eat between meals, eat large meals at lunch instead of dinner, and drink a few glasses of wine every day, especially red wine.
More recent research has looked at resveratrol and cancer. In a 1997 study, researchers reported that resveratrol inhibits the growth of cancerous cells in all three stages of the disease—stage one, when tumors are initiated; stage two, when the growth of cancer cells is promoted; and stage three, when uncontrolled growth of cancer cells leads to the formation of a tumor mass.
In other studies, resveratrol has been shown in cell cultures to limit cancer initiation caused by exposure to toxic chemicals and to slow the uncontrolled proliferation of leukemia cells.
In one eighteen-week study using animals, researchers applied cancer-causing chemicals to the shaved skin of 100 mice divided into 5 groups. One group received no resveratrol treatment. The other 4 groups received resveratrol in concentrations of 1, 5, 10, or 25 micromoles twice weekly and experienced a respective reduction in the number of tumors by 68, 81, 76, and 98 percent, compared with the untreated group. Similarly, the percentage of mice developing tumors decreased by 50, 63, 63, and 88 percent, respectively. The researchers observed no side effects from the resveratrol treatment.
Results of cell culture studies show that resveratrol is better than aspirin in reducing abnormal blood clotting that could otherwise lead to heart attacks and is almost as effective as the prescription medication indomethacin.
Further research may prove resveratrol to be a powerful weapon against both cancer and abnormal blood clotting. Meanwhile, Jim Duke’s second-favorite source of resveratrol is Mexican bamboo (Polygonum cuspidatum), which is used in Traditional Chinese Medicine to lower cholesterol and triglycerides, strengthen heart contractions, and treat bacterial and viral infections. In the spring, Jim grazes on the young shoots of Mexican bamboo growing near his home on the East Coast much in the same way he nibbles asparagus shoots and unfolding grape leaves, his favorite source of resveratrol.
C. Leigh Broadhurst holds a doctorate in geochemistry and is a nutrition consultant in Clovery, Maryland. James Duke spent thirty years working for the U.S. Department of Agriculture and is a member of the Herbs for Health Editorial Advisory Board.
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