Millions of seniors take ginkgo biloba, hoping that the herbal supplement will prevent or slow the progress of dementia. However, according to a study published in the Nov. 19 issue of The Journal of the American Medical Association, the product doesn’t have these benefits.

Researchers carried out a study of more than 3,000 people who didn’t have Alzheimer's disease at the beginning of the study. About half of them were given 240 milligrams a day of the Ginkgo biloba special extract EGb 761, an anti-dementia drug that improves cognitive functioning and stabilizes mood in cognitively impaired senior citizens. The rest of them were administered placebos. All participants were followed for an average of six years.

Researchers found that 18 percent of people taking ginkgo biloba were diagnosed with dementia, compared to 16 percent of those assigned to the placebo group. The first group also included 257 cases of Alzheimer (also known as Senile Dementia of the Alzheimer Type), whereas in the second one there were reported 220 cases of the disease. Based on the results of the clinical trial, researchers drew the conclusion that ginkgo doesn’t prevent or delay the progression of dementia.

"It was worth finding out if giving this relatively benign drug to older people would have an effect," said study researcher Steven T. DeKosky, vice president and dean of the University of Virginia School of Medicine. But as the findings revealed, the herbal remedy “cannot be recommended for preventing dementia."

Dementia, the gradual decline in cognitive function, currently affects an estimated 5 million U.S. residents. Alzheimer’s disease is the most common type of dementia, its causes and progression not being well understood yet.