Gingko biloba for Prevention of Dementia

Some posts back, I wrote about the use of Gingko biloba for the prevention of acute mountain sickness (AMS). Now there appears an article in the Journal of the American Medical Association (JAMA) [2008;30(19):2253-2262] entitled, "Gingko biloba for prevention of dementia: a randomized controlled trial," authored by Steven T. DeKosky et al.

The authors note that G. biloba is widely used for its potential effects on memory and cognition. They further note that prior to their clinical trial, there was no adequate investigation from which G. biloba's effects could be determined. So, their objective was to determine the effectiveness of G. biloba versus a placebo in reducing the incidence of all-cause dementia and Alzheimer disease in elderly persons with normal cognition and in those with mild cognitive impairment. In a statistically valid number of individuals, using twice-daily doses of 120 mg extract of G. biloba versus placebo, they concluded that this treatment regimen was not effective in reducing either dementia or Alzheimer disease.

There are many reasons offered for why G. biloba might be effective as a drug, including possible reduction of oxidative stress that perhaps leads to dementia or cerebrovascular disease, reduction of amyloid aggregation, or other effect(s). However, based upon this study, it does not appear that there is a benefit to taking G. biloba.

What is the implication of this for the outdoor medicine community? I think it highlights how little we know about drugs, supplements, and natural products that are often recommended as remedies, cures, and preventive agents for a wide variety of environmental medical problems, such as high-altitude illness, allergic reactions, snakebite, insect bite, marine envenomations, and others. We are still relatively early in our understanding of the pathophysiology of issue such as acute mountain sickness. We are becoming confident that it reflects a degree of brain swelling, but how much and why? Is there a logical reason why ingesting G. biloba would be expected to hasten acclimatization, or prevent or reverse a fundamental or subtle pathophysiological process related to hypoxia and brain dysfunction? The strength of our empirical observations will in large part be determined by designing and implementing large, statistically valid investigations, such as these authors did for looking at G. biloba and its (failed) effect on the prevention of dementia. Granted, in extrapolating from dementia to AMS, we may be comparing apples and oranges, but I am still cautioned about placing too much reliance on G. biloba for the prevention of AMS until someone can show me why it makes sense that it should be effective.

Tags: Gingko biloba, dementia, AMS, wilderness medicine, outdoor medicine, healthline

Labels: acute mountain sickness, AMS, dementia, Ginkgo, Ginkgo biloba

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Ginkgo biloba for Prevention of Acute Mountain Sickness

The fourth issue of Volume 18 of the journal Wilderness & Environmental Medicine has recently been published. The lead article is entitled "Ginkgo biloba Decreases Acute Mountain Sickness in People Ascending to High Altitude at Ollague (3696 m) in Northern Chile," authored by Fernando A. Moraga and his associates.

The article describes a study, the objective of which was to determine the effect of Ginkgo biloba in preventing acute mountain sickness (AMS) at an altitude of 3696 meters (12,126 feet) in participants without high-altitude experience. Thirty-six persons who reside at sea level were transported by ground transportation over 8.5 hours to an altitude of 3696 meters. The study participants were divided into three equal groups of 12 persons each. One group received Ginkgo biloba in a dose of 80 milligrams every 12 hours by mouth, one group received acetazolamide (Diamox, a drug commonly used to hasten acclimatization to altitude or to treat AMS) in a dose of 250 milligrams every 12 hours by mouth, and the final group received a placebo (e.g., no active drug). Each group began its treatment 24 hours before ascending and continued treatment during the 3-day stay at altitude. A standard Lake Louise Questionnaire was administered to determine the Self-Report Score, which is an accepted method for determining the presence and degree of AMS. In addition, selected physiological measurements were taken.

The results are the most compelling data to date supporting the efficacy of Ginkgo biloba in prevention of AMS. The group taking the Ginkgo biloba had no increase in their AMS score (which is remarkable), while the acetazolamide and placebo groups showed increases of 36% and 54%, respectively. The authors concluded that their study provides evidence supporting the use of Gingko biloba in the prevention of AMS, demonstrating that 24 hours of pretreatment with Gingko biloba and subsequent maintenance during exposure to high altitude are sufficient to reduce the incidence of AMS in participants with no previous high-altitude experience.

No doubt, others will attempt to replicate this investigation. If the results are corroborated, then Ginkgo biloba may prove to be a very useful adjunct in the prevention and treament of AMS.

Ginkgo biloba plant image courtesy of www.artofbonsai.org

Tags: Ginkgo biloba ,AMS, altitude, acetazolamide, high altitude, wilderness medicine, outdoor medicine, healthline

Labels: acetazolamide, acute mountain sickness, AMS, Ginkgo, Ginkgo biloba, high altitude, high altitude medicine

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