Ginkgo Biloba & The Brain
Ginkgo biloba may help improve memory, and could even protect against Alzheimer's.
September 1 , 2006
Researchers found significant improvement in verbal recall among a group of people with age-associated memory impairment, who took the herbal supplement ginkgo biloba for six months, when compared with a group that received a placebo.
The UCLA study used positron-emission tomography (PET) and found that for people taking ginkgo biloba, improved recall correlated with better brain function in key brain memory centres.
However, actual changes in brain metabolism, measured by PET for the first time, did not differ significantly between the study's two volunteer groups. Researchers noted that although all volunteers taking ginkgo biloba experienced better verbal recall, a larger sample size might be needed to effectively track brain metabolism results.
"Our findings suggest intriguing avenues for future study, including using PET with a larger sample to better measure and understand the impact of ginkgo biloba on brain metabolism," said Dr. Linda Ercoli, lead author of the study and an assistant clinical professor at the UCLA Neuropsychiatric Institute.
Gingko biloba is a Chinese herb often used as a dietary supplement to treat memory loss. The UCLA study and previous controlled clinical trials on ginkgo biloba's effects on verbal recall have yielded conflicting results.
"The research also raises questions regarding the significance of supplement quality and treatment duration," said principal investigator Dr. Gary Small, a UCLA professor on aging and director of the Aging and Memory Research Center at the UCLA Neuropsychiatric Institute. "The Food and Drug Administration does not regulate dietary supplements, and the quality of retail supplies varies widely. We used only the highest grade of ginkgo biloba in conducting our research."
Small also noted that the six-month UCLA study is one of the first to measure the effects of ginkgo biloba over a longer period of time. Most previous studies have measured the effect of the supplement over 12 weeks or less.
The study examined the impact of ginkgo biloba, compared to a placebo, in 10 patients, aged 45 to 75, who did not have dementia but complained of mild age-related memory loss. Four subjects received 120 mg of ginkgo biloba twice daily, and six received a placebo or inactive substance such as a sugar pill.
Researchers used cognitive tests to measure verbal recall and PET to measure brain metabolism before and after the treatment regimen. Magnetic resonance imaging was used to determine regions of interest to be examined by PET.
Funding for the study was provided by Dr. Willmar Schwabe GmbH & Co., the John Douglas French Alzheimer's Foundation, the Louis and Harold Price Foundation, the Larry L. Hillblom Foundation and the UCLA Center on Aging.
A study in France, published in the Journal of Gerontology, has revealed interesting results about the role of Ginkgo special extract EGb 761 in the prevention of Alzheimer's disease. Cognitive performance appears to be maintained for longer as a result of long-term treatment with Ginkgo special extract EGb 761. There also appears to be a positive effect in preventing the occurrence of Alzheimer's disease.
The primary objective of the Epidemiology of Osteoporosis (EPIDOS) study, a large-scale prospective multicentre study, was to investigate the risk factors associated with femoral neck fracture in elderly women. As numerous health-related data, including drug therapy, were recorded for the subjects over a period of 4 to 7 years, the study data bank lends itself to further analyses. The data analysis presented here investigated factors associated with the development of Alzheimer's disease.
The study enrolled a total of 7598 subjects of at least 75 years of age, 1462 of whom were in the Toulouse centre. On completion of the study, data on the cognitive status of 714 patients in the Toulouse centre were available. 414 who had no cognitive impairment at all on inclusion in the study (score of at least 8 in the Pfeiffer test) were selected from this patient group. Of these, 345 women were still cognitively unimpaired by the end of the study, 69 had developed dementia of the Alzheimer's type.
Interestingly, the women who still had their full cognitive faculties had taken medications such as the Ginkgo special extract EGb 761 or nootropics to stimulate blood circulation (category C4A medicines) significantly more frequently than the women who developed dementia. Additionally, the healthy women significantly more often had been taken these drugs for over 2 years or longer than the dementia patients. In contrast to the other C4A medicines, evidence of the anti-dementia effect of EGb 761 became apparent after only one year of taking this substance.
The findings of this study give every reason to believe that long-term treatment with Ginkgo special extract EGb 761 enables cognitive performance to be maintained for longer, and indicate that the development of Alzheimer's disease can be prevented or at least delayed.