Long-term use of ginkgo biloba supplements doesn't prevent seniors with memory problems from progressing to Alzheimer's disease, according to a large, multi-center study in France published online this week in The Lancet Neurology.
In the randomized, double-blind placebo-controlled trial, 2,854 men and women age 70 or older who had memory complaints received either 120 milligrams of ginkgo biloba extract twice a day or placebo. After five years, investigators used standard tests to assess the patients' memory, cognitive function and dementia status.
The research showed that 61 (4 percent) of those in the ginkgo group were diagnosed with probable Alzheimer's disease, compared with 73 (5 percent) of those in the placebo group. The difference was not statistically significant, and the researchers also found no significant difference between the groups in the number of participants who had died or had a stroke.
The results mirror those of a similar placebo-controlled study in 2008 by U.S. researchers who followed more than 3,000 people age 75 or older for roughly six years, and found that ginkgo did not decrease the incidence of Alzheimer's disease or other dementias in people with normal cognition or mild cognitive impairment.
An accompanying editorial notes that "some users will rationalize that, in the absence of effective treatments, ginkgo biloba could still possibly help and, appearing safe, will not harm them. Other users of ginkgo biloba, however, might now consider letting it go."
U.S. sales of ginkgo biloba supplements were about $90 million in 2011, according to data collected by the Nutrition Business Journal
Bottom line: Studies have not shown that ginkgo delays the onset of Alzheimer's. But people who exhibit signs of memory loss should consult a physician. "Although medications are not particularly effective, a work-up is almost always called for to rule out alternative causes of dementia such as small strokes (multi-infarct dementia), and to make sure that the symptoms are not due to other, reversible conditions, such as thyroid disease, vitamin deficiency, or metabolic abnormalities," says Orly Avitzur, M.D., a board-certified neurologist and Consumer Reports medical adviser. "Physicians will also review current medications to evaluate whether the cognitive impairment may be attributable to possible adverse effects of medication." For details about Alzheimer's disease medications, read our free Best Buy Drugs report.
Long-term use of standardised ginkgo biloba extract for the
prevention of Alzheimer's disease (GuidAge): a randomised
placebo-controlled trial [The Lancet Neurology]