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Ginkgo biloba as a memory booster? Forget about it.

December 29, 2009 |  1:01 pm

If you’ve made a New Year’s resolution to save money, here’s one suggestion: Stop buying ginkgo biloba pills to boost your brainpower.

Ginkgo is a popular – and unregulated – herbal remedy that was thought to prevent the cognitive decline associated with Alzheimer’s disease and general aging. It is prescribed by some doctors in Europe to preserve memory. On this side of the pond, the pills are touted for their ability to “improve mental sharpness, concentration, memory and cognitive ability,” according to one manufacturer.

There is some basic science to support that notion. According to this Los Angeles Times story from last year:

Ginkgo biloba contains flavonoids, whose antioxidant properties have been shown to combat the chemical damage that accumulates in aging brain cells. One laboratory study also found that ginkgo extract prevents the accumulation of beta-amyloid proteins which cluster into plaque in the brains of Alzheimer's patients.

"There are a lot of purported reasons why ginkgo might work," said Richard L. Nahin, a neuroscientist at the National Center for Complementary and Alternative Medicine, who worked on the study.

But as that story reported, a randomized clinical trial involving more than 3,000 senior citizens found that gingko biloba did nothing to prevent or delay dementia or Alzheimer’s disease.

Ginkgo Today, the same team of researchers from the National Center for Complementary and Alternative Medicine (NCCAM) and universities across the country reported that ginkgo also failed to reduce or slow cognitive decline in older adults.

About half the subjects – who ranged in age from 72 to 96 – took 120-milligram ginkgo tablets twice a day for an average of more than six years. The rest took an identical-looking placebo. All participants had normal mental function or mild cognitive impairment when the study began.

The rate of annual decline in cognitive function was the same for both groups, according to the new study published in the Journal of the American Medical Assn. The team didn’t find any differences even when looking at specific functions like memory, attention, visuospatial abilities, language, or executive functions. Age, sex, race, education and version of the apolipoprotein E gene (which is linked to risk of Alzheimer’s) also had no impact.

NCCAM, a branch of the National Institutes of Health, has been researching ginkgo for 10 years to see whether the type of clinical trials required for FDA-regulated pharmaceuticals would reveal any benefit. The new findings are in line with several other studies, including a Cochrane review published this year that found “no convincing evidence” that the herb preserves mental function in any way.

-- Karen Kaplan

Photo: It's time to give up on ginkgo, researchers agree. Credit: Robert Gauthier / Los Angeles Times