Med Watch: Ginkgo Biloba

Product: Ginkgo Biloba, 60 capsules (60 milligrams each), $5.89.

Key ingredients: Ginkgo leaves contain two types of chemicals (flavonoids and terpenoids) believed to have antioxidant properties.

The pitch: Memory and concentration enhancer, and anti-vertigo agent.

How it works: Some research suggests it can stimulate widening of the blood vessels, which leads to increased blood flow to the brain and lowered blood pressure.

Pros: Reviews of ginko studies suggest the herb can improve the symptoms of dementia, according to American Family Physician. A 1998 review by Oregon Health Sciences University reported that ginko extract improved mental impairment in Alzheimer’s patients by 10 percent to 20 percent, an effect comparable to that of the drug donepezil, the treatment of choice for the disease.

Cons: Ginko provides no measurable benefit in memory or cognitive function in healthy adults, according to a 2002 study sponsored by the National Institute on Aging. The number of experiments and reported effects are both small, so proof for even a mild benefit is weak, concluded a Scientific American article in April 2003. Ginkgo is commonly added to energy drinks, but the amount is typically so low it doesn’t produce a noticeable effect, except perhaps a placebo effect.

Bottom line: We’re skeptical, especially since most supplement dosages are much lower than the amounts used in studies.

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