Ginkgo May Help Prevent Alzheimer’s
By Alan R. Gaby, MD
Healthnotes Newswire (July 28, 2005)—A preliminary study published in the Journal of Nutritional Biochemistry (2004;15:749–56) suggests that leaf extracts of the Ginkgo biloba tree may help prevent Alzheimer’s disease. Ginkgo has long been known to improve brain (cognitive) function in older people and to favorably influence other signs of aging.
Ginkgo improves brain function in at least two ways: it increases blood flow to the brain and enhances metabolic activity in brain cells irrespective of the amount of blood reaching the cells. Ginkgo also functions as an antioxidant, and might therefore help prevent cellular free radical damage. Clinical trials have shown that supplementing with ginkgo can reverse the decline in cognitive function that often accompanies aging. Ginkgo has also been reported to improve other age-related problems, including ringing in the ears (tinnitus), vertigo, headaches, mood disturbances, erectile dysfunction, macular degeneration (an eye condition that results in loss of vision), and intermittent claudication (leg pain on walking caused by hardening of the arteries).
In Alzheimer’s disease, certain proteins in the brain degenerate to form plaques and deposits of debris known as amyloid. A major component of these plaques and amyloid deposits is called amyloid beta-peptide. It is not known why amyloid beta-peptide forms in brain tissue, although some researchers suspect that environmental exposure to aluminum is an important factor. Any treatment that inhibits amyloid beta-peptide formation might be expected to help prevent Alzheimer’s disease.
In the new study, the brain tissue of aged rats who had been fed a popular commercially available ginkgo supplement (Egb 761) for 28 days was analyzed. Compared with rats that were not given ginkgo, those receiving the herb had significantly reduced amounts of amyloid beta-peptide.
The results of this study should encourage clinical trials in humans, in order to determine whether ginkgo can prevent Alzheimer’s disease. Ginkgo supplementation has been associated with very few adverse side effects. There are several case reports of serious bleeding episodes occurring in people taking ginkgo; however, it was not clear whether ginkgo was the cause of these problems. The types of bleeding problems that were described in these case reports are known to occur spontaneously; therefore, the association with ginkgo use could have been a coincidence. To be on the safe side, people who have a bleeding disorder, are taking blood-thinning medications, or are scheduled for surgery should consult a doctor before taking ginkgo.
An expert in nutritional therapies, Chief Medical Editor Alan R. Gaby is a former professor at Bastyr University of Natural Health Sciences, where he served as the Endowed Professor of Nutrition. He is past-president of the American Holistic Medical Association and gave expert testimony to the White House Commission on Complementary and Alternative Medicine on the cost-effectiveness of nutritional supplements. Dr. Gaby has conducted nutritional seminars for physicians and has collected over 30,000 scientific papers related to the field of nutritional and natural medicine. In addition to editing and contributing to The Natural Pharmacy (Three Rivers Press, 1999), and the A–Z Guide to Drug-Herb-Vitamin Interactions (Three Rivers Press, 1999), Dr. Gaby has authored Preventing and Reversing Osteoporosis (Prima Lifestyles, 1995) and B6: The Natural Healer (Keats, 1987) and coauthored The Patient's Book of Natural Healing (Prima, 1999).
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