Ginkgo Biloba and Herbal Supplements

by Rich O’Boyle, Publisher
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Ginkgo biloba and other natural herbal supplements are increasingly popular as alternative remedies for numerous medical conditions. But caution must be exercised by individuals who are looking to these products to help relieve or cure medical conditions. While there is no evidence that widely available natural supplements are very dangerous, caution must be exercised in their use. Furthermore, the use of some supplements may not do any good either and may just be a waste of money.

Ginkgo biloba, a readily available natural product, has been the focus of recent media reports as a potential treatment for Alzheimer's Disease as well as useful for memory in general, even in folks without memory problems. Although a 1997 study in the United States suggests that a ginkgo extract may be of some help in treating the symptoms of Alzheimer's Disease and vascular dementia, there is no evidence that ginkgo biloba will cure or prevent Alzheimer's Disease.

In one of our recent educational chat sessions, Dr. Lawrence Honig from Columbia University’s Taub Institute said, “There is not good data to support Gingko's efficacy. With regard to vitamin E, there is theoretical work that would support it's use in a variety of neuro-degenerative conditions.” But he raised caution about the high doses used in clinical trials: “Dosages of vitamin E used in studies were very high, 2000 IU a day. At these doses vitamins are like medications, namely, they can cause harmful side effects. I would recommend consulting with a doctor.”

Specifically, some recent case studies imply that daily use of ginkgo biloba extracts may cause side effects, such as excessive bleeding, especially when combined with daily use of aspirin or other anti-coagulant drugs. Much more research is needed before scientists will know whether and how ginkgo biloba extracts benefit people.

Remember, supplements can have drug-like effects, which means that they can also interact with prescription drugs and even other supplements. Whenever you take dietary supplements, consider them just like prescription drugs. Tell your health professionals what supplements and drugs you and your loved are taking.

Uses Outside the United States

For centuries, extracts from the leaves of the ginkgo biloba tree have been used as Chinese herbal medicine to treat a variety of medical conditions. In Europe and some Asian countries, standardized extracts from ginkgo leaves are taken to treat a wide range of symptoms, including dizziness, memory impairment, inflammation, and reduced blood flow to the brain and other areas of impaired circulation. Because ginkgo biloba is an anti-oxidant, some claims have been made that it can be used to prevent damage caused by free radicals (harmful oxygen molecules). Although Germany recently approved ginkgo extracts (240 mg a day) to treat Alzheimer's Disease, there is not enough information to recommend its broad use.

Research in the United States

Researchers at the New York Institute for Medical Research in Tarrytown, New York, conducted the first clinical study of ginkgo biloba and dementia in the United States. Their findings were published in the Journal of the American Medical Association (October 22/29, 1997). These scientists examined how taking 120 mg a day of a ginkgo biloba extract affected the rate of cognitive decline in people with mild to moderately severe dementia due to Alzheimer's Disease and vascular dementia. At the end of the study, they reported a small treatment difference in people given the ginkgo biloba extract.

Three tests were used to measure changes in the condition of participants. First, participants showed a slight improvement on a test that measured their cognitive function (mental processes of knowing, thinking, and learning). Second, participants showed a slight improvement on a test that measured social behavior and mood changes that were observed by their caregivers. Third, participants showed no improvement on a doctor's assessment of change test.

Because 60 percent of the people did not complete the study, findings are difficult to interpret and may even be distorted. In addition, this study did not address the effect of ginkgo biloba on delaying or preventing the onset of Alzheimer's Disease or vascular dementia. The researchers recommend more investigation to determine if these findings are valid, understand how ginkgo biloba works on brain cells, and identify an effective dosage and potential side effects.

The National Institute on Aging (NIA) and the Office of Alternative Medicine, both at the National Institutes of Health, are funding a small study to test the effectiveness of ginkgo biloba in treating Alzheimer's Disease. This 2-year study at the Oregon Health Sciences University in Portland started in 1997. It will include 42 patients with mild to moderate Alzheimer's Disease.

Consulting With Your Doctor

People should consult with their family doctors before using ginkgo biloba extracts. This is especially true for those with disorders in blood circulation or blood-clotting and those taking anti-coagulants such as aspirin. Many different preparations of ginkgo biloba extract are available over the counter. They vary in content and active ingredients. Because not enough research has been done, no specific daily amount of a ginkgo biloba extract can be recommended as safe or effective at this time.

Anyone who is worried about a memory problem should see a doctor. Symptoms similar to those caused by Alzheimer's Disease may be caused by other medical conditions, including a high fever, dehydration, vitamin deficiency and poor nutrition, bad reactions to medicines, thyroid problems, depression, or a minor head injury. Medical problems like these are serious and should be treated by a doctor as soon as possible.

Other Common Herbal Supplements

Increasingly herbal supplements are being promoted for their medicinal properties. Every day we see advertisements on television, in magazines and on the Internet touting easy-to-swallow pills that contains naturally derived compounds that may (or may not) helps with the numerous problems of aging. Promoters suggest that various pills will improve or maintain one’s health, vision, joint flexibility, mood or mental state. It should be clear to consumers that this form of advertising is in a gray area and under constant scrutiny by drug regulators.

Popular herbal supplements derived from plants are increasingly appearing in sports drinks, herbal teas and food products. Read all product labels carefully and ask a salesperson about exotic ingredients that you may not recognize.

Ginseng is a plant root that has been used in Asia for centuries to for vitality and wellbeing, among other numerous conditions. While it is generally considered safe, there is some concern that it may adversely affect blood sugar levels. If you or your loved one is diabetic, it is a good idea to consult with your physician.

St. John’s Wort has increasingly been touted as “herbal Prozac.” Some believe that it can help elevate mood and act as an anti-depressant. While it may alleviate mild to moderate depression, and related anxiety and insomnia, physicians worry that people taking the supplement will not get proper psychological counseling. There are widespread concerns that it reduces the effectiveness of some prescription drugs.

Echinacea may enhance the immune system by stimulating the production of white blood cells. However, the flower from which the supplement is derived is related to ragweed, so some people have experienced mild allergic reactions.

Kava is commonly used to relieve anxiety and has also been used as an anticonvulsant. It is dangerous in conjunction with alcohol, sedatives or antipsychotics because it may cause sleepiness and even coma.

Remember, supplements can have drug-like effects, which means that they can also interact with prescription drugs and even other supplements.


  - Prism's Caregiver Education Series publishes an educational booklet on Managing Medicines Safely. You can purchase it online here...
  - U.S. Food and Drug Administration
  - National Center for Complimentary and Alternative Medicine

  -’s Herbs for Health Channel

Sources: National Institute on Aging, Herb Research Foundation and the University of Arkansas College of Pharmacy. Updated June 2001.

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