Ginkgo biloba is an herbal product that is used worldwide for improving memory and other cognitive functions in elderly people. It is thought to slow the cognitive decline in people suffering from Alzheimer’s disease. Many studies that have been conducted so far on ginkgo biloba had limitations in the form of low sample size, short duration, or combined administration of drugs. Hence, this study was performed to determine whether gingko biloba is useful in halting cognitive decline in elderly people. However, no evidence was found to show that ginkgo biloba reduces cognitive decline in older people.
The primary outcome analysis from the Ginkgo Evaluation of Memory (GEM) study had proved that ginkgo biloba has no capacity in decreasing the prevalence of Alzheimer’s disease. However, many smaller studies had shown that there were subtle beneficial effects, which over a period would delay the development of forgetfulness in old people. These studies also argued that ginkgo biloba delays the development of age-related cognitive impairment. The present study, which included 3,072 participants, was performed to assess the cognitive decline in participants of ginkgo-treated and control groups over a period. This study also examined whether sex, race, education, and APOE*E4 (APOE is a class of gene that provides instructions for making a protein called apolipoprotein E and combines with allele E4; allele is one of two or more forms of a gene) status had any role to play on the effect of ginkgo biloba.
* In this study, 7,709 individuals were screened and 3,072 participants were included. This recruitment into the study was conducted from September 2000 to May 2002. Old-aged individuals with normal or slightly low memory capacity were included.
* The baseline cognitive status, age, sex, race, education, and presence of APOE*E4 allele were examined.
* The participants were divided into two groups. The first group was given 120 mg of ginkgo biloba twice every day, while the second group was the control group that received placebo.
* At the start and then after every six months until August 2004, the cognitive capacity of all the participants was assessed. In the initial part of the study, the Modified Mini-Mental Status Examination was used. However, later on, a comprehensive test battery was administered to all the participants at study screening. The latter was able to measure memory, visual special construction, language ability, attention, and executive functions. These all are different elements of cognitive function.
* About 60 percent of the participants continued to take the medication given to them until the end of the study. This adherence was similar in both the groups. The mean age of the participants was 79 years; 95.5 percent were white and 54 percent were men. Of these, 38 percent reported to have education of more than 16 years.
* The baseline assessment showed that the participants in the placebo group performed slightly better in some of the tests such as memory test.
* The results showed that performance of all the participants reduced over a period. “The ginkgo biloba and placebo groups did not differ in rates of cognitive change for the global cognition score or any of the cognitive domains.”
* There was no noteworthy effect of age, sex, education, race, or APOE*E4 status on performance.
One of the important drawbacks of this study is the lack of a complete evaluation of cognitive function in the initial part of the study. Few baseline differences of cognitive functions were found between the study groups. Moreover, there was no proper representation of population, as almost 95 percent of the participants were white, and most of the participants were well educated. Hence, these findings cannot be generalized.
Alzheimer’s disease occurs due to the accumulation of a substance called amyloid in the brain. It was postulated that ginkgo biloba retards the amyloid deposition and development of Alzheimer’s disease. Some studies have shown that ginkgo biloba increases the blood supply to the brain, decreases blood thickness, and destroys free radicals in the brain. By this mechanism, it is able to slow down the aging process of the brain. However, the present study has convincingly shown that ginkgo biloba has no effect on improving the cognitive defects in aged people. This confirms the findings of some smaller studies, such as 2009 Cochrane review of ginkgo biloba for dementia, which showed results similar to this study.
For More Information:
Ginkgo biloba for Preventing Cognitive Decline in Older Adults
Publication Journal: The Journal of the American Medical Association, December 2009
By Beth Snitz, PhD; Ellen O’Meara, PhD; University of Pittsburgh, Pennsylvania; Johns Hopkins Medical Institutions, Baltimore, Maryland