Ginkgo May Help Prevent Altitude Sickness
By Dr. Edward R. Rosick
The public's enthusiasm for sports and activities that were once thought of as extreme has never been higher than it is today. So-called wilderness and adventure travel, which just a few years ago was the domain of only a few brave souls, has become mainstream. More and more people view activities such as mountain biking, mountain climbing, and high-altitude skiing as new ways to enjoy nature - witness the increased number of trekking permits issued in Nepal: from 14,000 in 1976 to almost 75,000 in 1996.
Getting High Can Make You Sick
The heightened enthusiasm for high-altitude sports has brought the risks and dangers of altitude sickness into the forefront of travel medicine. Even people who are otherwise in excellent physical shape can be incapacitated, or worse, when they travel from sea level (where the vast majority of people on the planet live) to heights beyond about 2400 meters (7900 feet). Studies show that about 25% of travelers who venture from sea level to elevations between 2000 and 3000 meters will experience some form of altitude sickness; at elevations above 3000 meters, over 50% of such people will become ill.1
The primary cause of altitude sickness is lack of oxygen (hypoxia in medical terminology). Although the percentage of oxygen in the air (21%) does not change with increasing altitude, the air density does. The higher you go, the thinner the air, and the fewer the oxygen molecules (as well as nitrogen molecules) you inhale with each breath.
Your Brain Is an Oxygen Hog
The human brain, which weighs about 3 pounds (about 1-3% of total body weight), uses an incredible 20% of the oxygen in every breath inhaled. Without adequate oxygenation, the brain cannot function normally, and all kinds of problems arise, the worst being death. We all know that most people who go to the mountains to climb or ski won't die, but that doesn't mean they won't suffer the effects of altitude sickness.
The most common form of altitude sickness is acute mountain sickness, or AMS. With less oxygen available for the brain, symptoms such as headache, dizziness, insomnia, and fatigue can plague even the most well-conditioned person. Most if not all the symptoms of AMS occur within the first 48-72 hours after rapidly ascending from sea level to mountainous areas. The symptoms are generally worse at night, because a person's respiratory rate decreases during sleep, so less oxygen is taken in than during the day.
AMS can usually be prevented by taking two to three days to ascend into the mountains, but this isn't practical for most people, for whom a ski weekend means going from sea level to the mountains in a matter of hours, not days.1
HAPE and HACE - High-Altitude Killers
While AMS can certainly ruin a vacation in the mountains, there are more serious forms of altitude sickness that can be life-threatening. One is high-altitude pulmonary edema(HAPE), which is most often seen in people who ascend too quickly from sea level to altitudes of over 10,000 feet. In fact, when the ascent occurs in less than 24 hours, such as one might experience in flying from Los Angeles to Denver and then driving into the high country of the Rockies, the incidence of HAPE is about 10%. The symptoms include rapid heart and respiration rates, severe cough, and fluid in the lungs. HAPE can be remedied only by quickly descending to a lower altitude or by using supplemental oxygen.
Ginkgo and vinpocetine provide a
variety of benefits. By improving
blood flow to the brain, they tend
to improve memory and other
cognitive functions.
Another form of altitude sickness that occurs under the same circumstances is high-altitude cerebral edema (HACE). Symptoms include severe loss of coordination, extreme fatigue, visual disturbances, confusion, and disorientation. As with HAPE, the remedy for HACE is a rapid descent to a lower altitude or the use of supplemental oxygen. If these steps are not taken, both HAPE and HACE can be fatal, but deaths rarely occur except at extremely high altitudes, such as in the Andes or Himalayas.
Drugs for AMS Can Be a Drag
The best way to prevent altitude sickness and the serious health risks it poses is to take your time going from sea level to high altitude - but, as we have seen, that's often impractical. Another way is to use supplemental oxygen - but who wants to carry around a tank of oxygen all day? If your vacation happens to be in the Andes, a popular remedy for altitude sickness is mate de' coca - literally, a tea made from coca leaves. Although locals swear by its efficacy, it would be extremely unwise to try to import coca leaves for any use (tea or otherwise!) into the United States.
The prescription drug acetazolamide (Diamox®), used to treat glaucoma and seizures, is also used to prevent or treat AMS, because it improves oxygenation of the blood and the release of oxygen from the red blood cells. Unfortunately, Diamox can have multiple side effects, including nausea, diarrhea, fatigue, frequent urination, and fever, along with possible kidney and liver toxicity. Another drug, dexamethasone, has also been used to prevent AMS, but the results have been mixed, and its side effects include ulcers, cataracts, and depression.
Ginkgo biloba - Ancient Remedy for a Modern Ailment
Fortunately for high-altitude sports enthusiasts, there is Ginkgo biloba, a safe, natural, herbal supplement that has shown promising results in studies of its effectiveness in preventing altitude sickness. Ginkgo biloba is a tree that, according to paleobotanists, has not changed appreciably in over 200 million years. For at least the past 5000 years, extracts of the leaves of the ginkgo tree have been used to treat a variety of medical conditions.
Ginkgo is known to exert its positive effects on human health in a variety of ways. In terms of acute mountain sickness, two of its most important effects are its ability to improve blood circulation and its ability to allow the brain to tolerate low oxygen levels.2In recent years, two groups of researchers have examined the effectiveness of ginkgo in preventing the symptoms of AMS, and both studies showed that it can help prevent the most common symptoms.
Two Studies, Similar Positive Results
The first study looked at the effects of ginkgo on a group of 44 healthy male climbers who had experienced symptoms of AMS on previous climbs.3 The men were randomly divided into two groups - one group received 160 mg/day of Ginkgo biloba extract, while the other group received a placebo. The trial took place in the Himalayas, where the group climbed.
When the snow cleared, so to speak, it turned out that the treatment group showed far fewer symptoms of AMS than the control group. With ginkgo, in fact, there were no reported symptoms related to brain hypoxia, such as headache, dizziness, insomnia, or nausea. By contrast, 41% of the control group did report such symptoms. Also, only 14% of the ginkgo group, but 82% of the control group, reported respiratory symptoms such as undue shortness of breath at rest or upon exertion.
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Alzheimer's disease, the most common form of dementia in those aged 65 or older, is expected to afflict over 14 million people in the United States in the next few decades. A measure was recently introduced in the U.S. Senate calling for increased research into this devastating disease. Although much of the research will focus on prescription drugs, other methods for treating Alzheimer's - including Ginkgo biloba - are getting serious attention. In 1997, a randomized, placebo-controlled, double-blind trial of a standardized ginkgo extract on patients with Alzheimer's disease showed that ginkgo was capable of stabilizing and even improving their cognitive performance and social functions for 6 months to 1 year.1 A more recent study showed that Alzheimer's patients given 120 mg/day of ginkgo improved on cognitive assessments, regardless of the severity of their condition.2 There was no difference in the safety profiles of the patients taking ginkgo or placebo. Those who scoff at using herbal remedies such as ginkgo to prevent or treat Alzheimer's would do well to remember that some medications now embraced by mainstream medicine are based on nutritional supplements that were in folkloric use long before they became hot-selling (and expensive) prescription drugs. One example is galantamine, a natural herbal product with a long history of use in Europe. It is now sold as the prescription drug Reminyl® for treating Alzheimer's disease, but it is also available without prescription. Galantamine has been subjected to rigorous scientific testing and has been shown to be particularly effective in combating the debilitating symptoms of Alzheimer's.3
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The second study looked at ginkgo for combating AMS in both sexes.4 In this randomized, double-blind study, 40 college-age men and women were given 120 mg of either ginkgo or placebo twice daily for five days before starting an ascent of Pikes Peak in Colorado. The group started their climb at 1400 meters (about 4600 feet) and climbed to 4300 meters (about 14,100 feet) in one day. As in the previous study, those people taking ginkgo reported significantly fewer symptoms of AMS than those taking placebo.
Vinpocetine Is Also a Brain Booster
If ginkgo can help protect against altitude sickness through its ability to improve blood flow, and thus oxygen delivery, to the brain, it stands to reason that other supplements with this ability may also be helpful. Vinpocetine, a compound extracted from the common periwinkle (Vinca minor), has been shown in multiple studies to help increase blood flow to the brain.5 In fact, vinpocetine is widely used in Europe and Japan to treat the symptoms of ischemic stroke, in which the blood supply to a portion of the brain is cut off by blockage of an artery, resulting in severe oxygen deprivation.6
Although vinpocetine has not been as widely studied as ginkgo for altitude sickness, there are indications that this safe, nontoxic, natural supplement might be as useful as ginkgo in preventing the symptoms of AMS.7
Ginkgo and Vinpocetine Are for Everyone
You don't need to plan your next vacation in Nepal to enjoy the health benefits of Ginkgo biloba or vinpocetine. Both of these nutrients provide a variety of benefits (see the sidebar), even for those whose idea of high altitude is climbing a stepladder. By improving blood flow to the brain, in particular, they tend to improve memory and other cognitive functions, making for a sharper mind - and probably a happier person, because much of life's pleasure, especially as we grow older, lies in the fond memories of times past with the ones we loved. So "get high" on ginkgo and vinpocetine!
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Scientific research has demonstrated that Ginkgo biloba helps to:1
Scientific research has demonstrated that vinpocetine helps to:2
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Multicognitive Enhancers Ginkgo biloba and vinpocetine, as well as pregnenolone, citicoline, choline, dimethylaminoethanol (DMAE), phosphatidylserine, docosahexaenoic acid (DHA),and pantothenic acid (vitamin B5) are all well established in the scientific literature to be of value in supporting the mechanisms of the brain - from its cell membrane integrity to its energy production, its bioelectrical patterns, and its neurotransmitter functions. |
References
- Weiss EA. Medical considerations for wilderness and adventure travel. Med Clin N Amer 1999;83(4):885-902.
- Blumenthal, Busse, Goldberg, et al. The Complete German Commission E Monographs. The American Botanical Council, Austin, Texas, 1998.
- Roncin JP, Schwartz F, D'Arbigny P. EGb 761 in control of acute mountain sickness and vascular reactivity to cold exposure. Aviat Space Environ Med1996;67(5):445-52.
- Leadbetter G et al. Ginkgo biloba reduces incidence and severity of acute mountain sickness. High Alt Med Biol 2001;2(1):110-6.
- Bonczk P et al. Role of sodium channel inhibition in neuroprotection: effect of vinpocetine. Brain Res Bull 2000;53:245-54.
- Feigin VL et al. Vinpocetine treatment in acute ischaemic stroke: a pilot single-blind randomized clinical trial. Eur J Neurol 2001;8(1):81-5.
- Memeo SA, Data PG, Modugno GC. Pharmacology of (-) eburnamonine as studied in a scientific expedition to the Peruvian Andes. Med Sport 1980;33:331-8.
Dr. Rosick is an attending physician and clinical assistant professor of medicine at Pennsylvania State University, where he specializes in preventive and alternative medicine. He also holds a master's degree in healthcare administration.