Ginkgo biloba, derived from the leaves of the gingko tree, is one of the best-selling herbal remedies in the United States. It is an anticoagulant, or blood thinner, and it increases blood flow throughout the body. This effect is under study for its potential benefits in treating poor blood circulation, glaucoma, Grave's disease, multiple sclerosis and many other conditions. The anticoagulant effect is also one of its biggest risks—hemorrhaging or bleeding into the internal organs. As with any herbal product, consult a doctor before using.
An Exhaustive Study of Gingko
Although used medicinally for centuries for a variety of conditions from memory loss to sexual dysfunction, Ginkgo biloba's alleged benefits have yet to be confirmed in rigid scientific trials. And there are some significant risks associated with its use. A eight-year study of 3,000 participants between 72 and 96 years old conducted in six academic medical centers in the United States found that daily doses of Gingko biloba did not slow cognitive decline in older adults. The results of this study were published in the "Journal of the American Medical Association" in 2009.
No Evidence Ginkgo Prevents Cognitive Decline
Participants in the study on the effectiveness of ginkgo biloba for preventing cognitive decline in older adults were tested in the areas of memory, attention, language, visual-spatial construction and executive mental functions. Rates of cognitive decline between those who took 120 mg of ginkgo biloba twice daily and those who were given placebo did not differ significantly, according to the study. "A single study rarely provides a complete picture of the benefits and risks of any herb or drug," explains Brent Bauer, MD, of the Mayo Clinic. "However, in this case, ginkgo biloba doesn't appear to be living up to its earlier promise."
While some studies suggest that ginkgo biloba may benefit people with painful legs caused by clogged arteries, or intermittent claudication, it is not clear whether the herb is as effective as exercise or prescription drugs, according to the National Institutes of Health.
Risks of Taking Ginkgo Biloba
Whatever its benefits, ginkgo biloba also has been shown in a recent large clinical trial conducted under the auspices of the National Institutes of Health to be ineffective in treating tinnitus, or ringing in the ears.
Among the health risks of ginkgo biloba are internal bleeding, poisoning from eating seeds, skin blistering, dizziness, headache, diarrhea and tachycardia, or racing heartbeats. Bleeding problems can range from nosebleeds to potentially fatal bleeding when ginkgo biloba is taken with other anticoagulant drugs. In some people, gingko biloba sets off an allergic reaction that includes skin blistering and sloughing. Ginkgo may also affect insulin and blood sugar levels. Serum glucose levels may need to be monitored when people with diabetes or low blood sugar take ginkgo.
Interactions With Other Drugs
Ginkgo biloba can increase the bleeding risks of people who also take aspirin, warfarin, heparin, anti-platelet drugs, as well as non-steroidal anti-inflammatory drugs such as ibuprofen or naproxen, according to the National Institutes of Health. Ginkgo may cause adverse interactions with other drugs such as monoamine oxidase inhibitors, anti-psychotic drugs and antiseizure medications. Ginkgo is suspected of changing the way the liver metabolizes certain drugs, herbs and supplements, as well as augmenting the effects of remedies for erectile dysfunction such as yohimbe.
Because of the numerous side effects, interactions and risks of ginkgo biloba, a prudent course is to notify your healthcare provider if you are taking it or plan to take it.
Doses and Outcomes May Vary Widely
The U.S. Food and Drug Administration does not regulate herbal supplements and remedies sold over-the-counter, so these products may vary in strength and purity. Effective dosing is, therefore, difficult to measure, as are outcomes of these supplements when taken internally.
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