Ginkgo biloba may delay the onset of memory loss among elderly people, so long as they take the herbal supplement regularly, suggests new research published in the Feb. 27 edition of Neurology.
However, ginkgo might also increase the incidence of stroke, results showed.
A research team led by Dr. Hiroko H. Dodge of Oregon State University in Corvallis studied 118 people, age 85 and older, without memory problems. Half the group was instructed to take ginkgo biloba extract three times a day and half were given a placebo.
Over the course of the three-year study, 21 people developed mild memory problems. Among them, 14 had taken the placebo and seven the ginkgo extract. While that difference implies ginkgo had a positive effect, the gap is not statistically significant, say the researchers.
More telling, they said, is that those people who reliably took the ginkgo pills as instructed (adherence varied within the ginkgo group) had a 68 percent lower risk of developing mild memory problems than people who took the placebo.
"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 Dodge in a statement. "The potential to delay or prevent this is of great importance."
He said larger studies are needed to clarify their findings.
"This is an interesting study with intriguing preliminary results in those 85 and older. However, it is in a small sample, thus, the value of ginkgo in the elderly will really need further verification with larger samples," said Catherine Stoney, program officer for the National Center for Complementary and Alternative Medicine. The ginkgo study was supported by grants from NCCAM and the National Institute on Aging, both agencies within the National Institutes of Health.
Of concern, seven of the subjects who took the ginkgo extract experienced strokes or "mini-strokes" compared with none of the people in the placebo group. The reasons were unclear.
"Ginkgo has been reported to cause bleeding-related complications, but the strokes in this case were due to blood clots, not excessive bleeding, and were generally not severe," said Dodge.
Ginkgo is marketed as a memory enhancer, and it is a popular ingredient in many energy drinks, because some studies have reported that GBE improves attention in healthy adults. Other studies suggest that the herb, which contains potent antioxidants, may improve blood flow to organs and protect against cell damage caused by free radicals.