Memory problems don't shrink from ginkgo, study finds

An extract from the leaves of ginkgo biloba trees, touted to improve brain power, didn't stop people age 85 or older from developing memory problems and may increase the risk of stroke, a study found.

Seven people who took the herbal supplement three times a day for as long as 42 months developed mild memory problems, compared with 14 people who were given a placebo, a difference that wasn't statistically significant, according to research in Wednesday's online issue of the journal Neurology.

This was the first study to use ginkgo in healthy older people in an attempt to prevent dementia, said David Knopman, a professor of neurology at the Mayo Clinic in Rochester, Minn. The findings don't support taking the supplement to stave off Alzheimer's disease, said Knopman, who edited the study for the journal and wasn't involved in the research.

"I personally don't recommend taking it to people who are either worried about developing Alzheimer's disease or who have Alzheimer's disease," he said in a telephone interview. "I don't think there ever was a rationale to take it in the first place, other than wishful thinking."

A 2002 study in the Journal of the American Medical Association found that ginkgo didn't improve learning, memory, attention or concentration in healthy adults older than 60.

Researchers in Wednesday's study reported on 118 people ages 85 and older who had no memory problems at the start of the research. Half took ginkgo and the others received a placebo.

The scientists found that seven people taking ginkgo had strokes, compared with none of those on placebo. The strokes were caused by blood clots, not excessive bleeding. Ginkgo has been linked to bleeding-related complications, the authors said.

"One of the most pressing public health problems facing our society is the rapidly growing number of people who, due to their age alone, are at high risk of developing dementia," said lead author Hiroko Dodge, of Oregon State University's Department of Public Health, in Corvallis, in a statement. "The potential to delay or prevent this is of great importance."

Americans' spending on ginkgo supplements declined 3 percent in 2006, to $106 million, according to the Nutrition Business Journal, a Boulder, Colorado-based publication that monitors botanical-product sales.

The journal Neurology is published by the American Academy of Neurology, a professional society based in St. Paul, Minnesota.