Gingko may help people with Alzheimer's disease

Better Nutrition, Jan, 1998 by Victoria Dolby

Few scientific breakthroughs have occurred with Alzheimer's disease since 1907, when Alois Alzheimer first identified brain changes characteristic of the progressive mental disease that now bears his name. That is, until recently.

Several major studies have been published over the past 12 months offering a ray of hope to families affected by this devastating illness. Perhaps the flood of new research can be traced to the burgeoning legions of Baby Boomers heading into their older years, and fearful of the many age-related illnesses that nature could have in store.

First, there was the announcement from the Alzheimer's Disease Cooperative Study that high doses of vitamin E (2,000 I.U. per day) over a two-year period preserves the day-to-day basic functioning capability of those afflicted with the mind-robbing disease of Alzheimer's. Now there's the research presented at an American Medical Association conference showing that the ancient herb Ginkgo biloba ("ginkgo") helps preserve reasoning, memory, and behavior in Alzheimer's patients.

Understanding Alzheimer's disease

An estimated four million Americans are afflicted with Alzheimer's disease; in fact, it is the fourth leading cause of death among adults, accounting for about 10,000 deaths each year.

Although this mortality rate is alarming, the most tragic aspect of Alzheimer's disease is the loss of memory, reasoning power, and ability to carry out daily functions that Alzheimer's victims suffer in the years -- and sometimes decades -- before death. The loss of cognitive function is known as dementia, a condition that is primarily associated with Alzheimer's disease.

Antioxidant nutrients, by disarming free radicals before they damage key cell components, can act as "antidotes" to the free radical-induced changes that may precede Alzheimer's disease.

In fact, the two recent studies demonstrating that vitamin E and ginkgo aid Alzheimer's patients share an underlying commonality: both of these nutrients are antioxidants.

Good news about ginkgo

Ginkgo biloba is the oldest living species of tree, and ginkgo leaves have been used medicinally for at least 5,000 years for the treatment of memory loss in the elderly, among other benefits. Modern research now confirms this ancient application for ginkgo.

According to Pierre Le Bars, Ph.D., M.D., and fellow researchers from the New York Institute for Medical Research, almost one-third of Alzheimer's patients taking ginkgo supplements showed improvements in cognitive function during a double-blind clinical trial comparing ginkgo supplements with a placebo.

Le Bars' study enrolled 327 patients with dementia (caused by either Alzheimer's disease or stroke) and randomly assigned them to take either ginkgo supplements or look-alike placebo pills every day for one year. The ginkgo supplements provided 120 mg of a standardized concentrated extract known as EGb. Of the initially enrolled group, only 137 patients completed the entire study -- some patients were dropped from the study because they developed other, unrelated illnesses, some did not take the scheduled amounts of supplements, and others were withdrawn from the study by their caregivers.

Study results show improvement

After about six months of daily supplement use, the ginkgo group showed better results on standard tests of reasoning, memory, and behavior. Meanwhile, the group taking placebos showed worsening test results, which would be expected with the progressive nature of Alzheimer's disease.

In other words, Le Bars explains that "EGb appears to stabilize And, in an additional 20 percent of cases vs. placebo), improve the patient's functioning for periods of six months to one year. Regarding its safety, adverse effects associated with EGb were no different from those associated with [the] placebo."

How does it do it? Well, according to Le Bars, and colleagues, "the mechanism of action of" ginkgo is "only partially understood," although the main effects seem to be related to its antioxidative properties, involving compound families in the herb, including flavonoids, terpenoids (ginkgolides, bilobalide), and organic acids.

REFERENCES

Le Bars, P.L., Katz, M.M., Berman, N., et al. "A placebo-controlled, double-blind, randomized trial of an extract of ginkgo biloba for dementia," JAMA 278(16):1327-1332, 1997.

Drachman, D.A., and Leber, P. "Treatment of Alzheimer's disease -- Searching for a breakthrough, settling for less," New Engl J Med 336:1245-47,1997.