Ginkgo Does Not Prevent Alzheimer’s

By: Dr. Pascale Michelon

Ginkgo biloba is one of the top selling herbs in the United States. A new study nevertheless confirms that Ginkgo does not prevent or delay Alzheimer’s disease.

Why Ginkgo Biloba?
Ginkgo extracts, usually taken from the ginkgo leaf, are used to make tablets, capsules, or teas. They contain flavonoid which are most commonly known for their antioxidant activity. Since oxidative stress may accelerate Alzheimer’s disease pathology, antioxidants may have a beneficial effect on Alzheimer’s incidence.

Most Recent Study
The most recent study on the effect of Ginkgo was conducted in multiple centers in France. This randomized, double-blind trial involved over 2,800 men and women age 70+ who had memory complaints. Half of the participants received 120 milligrams of ginkgo biloba extract twice a day and the other half, a placebo. They were all given yearly cognitive tests to assess their memory, cognitive function and dementia status and were followed for up to five years. About 70% of them took the ginkgo biloba or placebo pills during the entire study.

In the ginkgo biloba group, 61 people (4%) were diagnosed with probable Alzheimer’s disease versus 73 people (5%) in the placebo group. The difference was not statistically significant, meaning it could have occurred by chance. The researchers also found no significant difference between the groups in terms of number of participants who died or had a stroke.
Interestingly, the study was paid for by Ipsen, a producer of ginkgo biloba supplements.

In Sum
These results confirm the ones found by the 2008  largest US independent clinical trial to assess ginkgo biloba effects on Alzheimer’s. The study, known as the Ginkgo Evaluation of Memory study, was a randomized trial that included more than 3000 volunteers aged 75 years or older with normal cognition. Participants received either 120 mg twice a day of ginkgo extract or a placebo and were followed for an average of 6 years. Results showed that ginkgo biloba was not effective in reducing the overall incidence rate of dementia.

There is now ample evidence that ginkgo does not help prevent the emergence of Alzheimer’s disease neither in healthy individuals nor in people who have memory complaints. Some experts cautiously say that we may need longer studies to observe  any effects. Others now suggest that there is enough evidence to stop taking ginkgo.
An alternative solution to taking supplements may involve regular physical exercise, a balanced diet and mental challenge, as these factors are backed-up by much stronger evidence as to their effects on cognitive health.

References

  • DeKosky, S. T., et al. (2008). Ginkgo biloba for prevention of dementia: A randomized controlled trial. JAMA, 300, 2253-2262.

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