Ginkgo doesn’t prevent or reduce dementia, study says
Are you taking ginkgo biloba to ward off dementia and its accompanying loss of memory? Well, forget it.
The largest clinical trial ever to assess the effects of the popular supplement found that it does not appear to prevent dementia or memory-destroying Alzheimer's disease, researchers at Wake Forest University and elsewhere reported Tuesday.
The study followed more than 3,000 senior adults for an average of six years. Half the subjects were given 240 mg daily of ginkgo biloba, half a placebo.
During the study, dementia was diagnosed in 523 participants, 246 in the placebo group and 277 in the ginkgo group. Researchers concluded that ginkgo showed no overall effect for reducing all types of dementia or the memory-destroying Alzheimer's disease.
The $30 million study was funded by the National Institutes of Health and released Tuesday by the Journal of the American Medical Association.
The findings weren't quite what researchers had expected.
"In addition to its widespread use based on the belief that it helps memory function," Wake Forest researcher Dr. Jeff Williamson said, "ginkgo biloba had enough promising circumstantial evidence from laboratory and animal studies and enough safety information to warrant a full-scale test in humans."
The supplement is an extract derived from the leaves of the ginkgo tree.
It has long been touted as a health aid, particularly in the areas of memory and concentration. It is among the most widely used supplements, with annual U.S. sales topping $1 billion.
But a 2002 study, also published in the Journal of the American Medical Association, found that the supplement did not affect memory and related cognitive functions in test subjects older than 60 with no known cognitive problems.
Based on his research, Williamson called it "very unlikely" that the supplement helps prevent dementia at any dose over five years and also unlikely that it works in people older than 75.
"It is also ineffective in people with signs of early memory loss," Williamson said. "What is not known yet is whether the effect of ginkgo biloba might require taking the drug for many, many years, say 15 years, before there is even a sign of memory loss."
Williamson said the millions of people spending their money on over-the-counter ginkgo to protect themselves from dementia and Alzheimer's disease should spend their money on other things while remaining mentally and physically active.
One bright spot: The study showed that conducting large-scale dementia-prevention studies in older adults is feasible.
That finding likely will help allocate Medicare dollars more efficiently in the future, Williamson said.
Contact Lex Alexander at 373-7088 or lex.alexander@news-record.com
