Researchers report in the journal Neurology that reliably taking the supplement could reduce the risk of developing mild memory problems by 68 per cent in healthy older people with no memory problems. On the other hand, in the general study population with differing levels of compliance no overall benefits were observed for gingko. Moreover, there were suggestions that the extract may lead to an increased risk of stroke, report the researchers, led by Hiroko Dodge from Oregon State University. "To our knowledge, our study is the first to report the results of a dementia prevention RCT among oldest old subjects," wrote the authors. "The suggestive results of a protective effect of GBE found in our study needs to be confirmed by ongoing larger prevention studies such as the Ginkgo Evaluation of Memory study in the US and the European GuidAge study." Ginkgo is derived from the leaves of the ginkgo tree and has been used for thousands of years by the Chinese as a herbal remedy for a variety of ailments. It contains potent antioxidants called flavoglycosides that have been shown to have neuro-protective effects in animal models of spinal cord injury. Previous clinical trials in Germany and France reported that gingko biloba produced long-term improvements in cognitive function in older adults with dementia, but, a study by Joseph Carlson and co-workers from Stanford University reported no benefits for the herbal in healthy, non-demented older adults (Journal of the American Dietetic Association, March 2007, Vol. 107, pp. 422-432). Similar results in the new study were reported when the researchers looked at the overall population. New data The new study involved 118 people age 85 and older with no memory problems. The elderly subjects were randomly assigned to receive either a ginkgo biloba extract (240 mg daily, provided by Thorne Research) or placebo for three years. The extracts were independently verified to contain at least six per cent terpene lactones and 24 per cent flavone glycosides. Dodge and co-workers report that, during the course of the study, 14 people taking the placebo developed mild memory problems, while only seven people developed such problems after taking the ginkgo extract. Although there was a trend favouring ginkgo, the difference between those who took gingko versus the placebo was not statistically significant. Interestingly, when the researchers considered only people who followed the directions in taking the study pills, they found that people took at least 84 per cent of the supplements as directed had a 68 per cent lower risk of developing mild memory problems, compared to those taking placebo. On a cautionary note, a slight increase in the risk of a stroke or mini stroke was observed for those taking the gingko supplements, with seven people taking ginkgo experiencing strokes, compared to none in the placebo group. "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. "These results need to be clarified with larger studies, but the findings are interesting because ginkgo biloba is already widely used, readily available, and relatively inexpensive," said Dodge. "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. The potential to delay or prevent this is of great importance. Further studies are needed to determine whether gingko biloba has any benefits in preventing cognitive decline and whether it is safe." The study was supported by grants from the National Institute on Aging and the National Center for Complementary and Alternative Medicine (NCCAM). Source: Neurology Doi: 10.1212/01.wnl.0000303814.13509.db "A randomized placebo-controlled trial of ginkgo biloba for the prevention of cognitive decline" Authors: H.H. Dodge, T. Zitzelberger, B.S. Oken, D. Howieson, J. Kaye
Supplements of ginkgo biloba may boost the memory and memory function of the elderly, so long as people comply and take them as instructed, according to the results of a new randomised clinical trial (RCT).