A new large study has dashed hopes that the dietary supplement ginkgo biloba can protect against age-related dementia and Alzheimer’s.
In the largest clinical trial ever to evaluate the impact of gingko biloba supplements on the development of dementia, the results have come up flat, says study author Steven DeKosky, vice president and dean of the University of Virginia School of Medicine. DeKosky’s research appears in today’s Journal of the American Medical Association.
“We’re hugely disappointed. It could have saved hundreds of thousands of people from getting the disorder,” DeKosky says.
The new study puts to rest the questions previous studies have raised about the effectiveness of ginkgo biloba as a memory preserver, says Lon Schneider, professor of psychiatry, neurology and gerontology at the University of Southern California, who wrote an accompanying editorial in the medical journal.
Schneider says ginkgo’s antioxidant properties, previously isolated in the lab, had led researchers to believe the plant-derived supplement would be beneficial to brain health.
For the government-funded study, DeKosky and colleagues tested the effectiveness of 120 milligrams of ginkgo twice daily versus a placebo in diminishing dementia and Alzheimer’s in more than 3,000 volunteers. The participants were 75 or older and had normal cognitive health or only mild cognitive problems at the study’s launch in 2000. They were followed up every six months for six years.
There was negligible difference between the supplement and placebo takers by study’s end. Of the 523 who developed dementia, 246 received the placebo, and 277 took ginkgo.
“This will be a wake-up call for all those who spend hundreds of dollars on unproven memory cures,” says Murali Doraiswamy, an Alzheimer’s expert from Duke University. According to Nutrition Business Journal, consumers now spend more than $100 million a year on ginkgo supplements.