Ginkgo Biloba and Memory
How effective are ginkgo biloba supplements?
The supplement ginkgo biloba is promoted as a natural way to improve memory, fight age related memory loss and reduce Alzheimer's dementia. It's become so closely associated with memory improvement, that many companies put ginkgo biloba and the word "memory" together on their boxes or packaging.
The association is deliberate. Supplement companies imply that if you take a ginkgo biloba supplement, you'll have better memory. But a closer inspection reveals something quite different. They don't actually say ginkgo improves memory. They use words like "enhance" and "support", because according to the Food and Drug Administration, those are medically meaningless words. ANYTHING can be said to "support" or "enhance" ANY bodily function.
The reason they can't say ginkgo supplements IMPROVE memory, is because the clinical studies show it doesn't.
The largest clinical trial ever conducted to test the effects of ginkgo biloba on dementia was called the GEM study. (Ginkgo biloba for the Evaluation of Memory). 3,069 elderly individuals were recruited and given either 120 milligrams of ginkgo twice daily, or a placebo. The people in the study were either normal or had only mild cognitive impairment. Researchers then followed them for an average of 5.8 years.
The GEM study took eight years and cost $36.5 million dollars. The research was conducted by five components of the National Institutes of Health (NIH): National Center for Complementary and Integrative Health (NCCIH); National Institute on Aging; National Heart, Lung, and Blood Institute; National Institute of Neurological Disorders and Stroke, and the Office of Dietary Supplements.
In the end, the conclusion was devastating to ginkgo promoters. "In this study, ginkgo at 120 milligrams twice a day was neither effective in lowering the overall incidence rate of dementia nor Alzheimer's disease incidence in normal elderly or elderly people with mild cognitive impairment." In other words, ginkgo was no better than a sugar pill.
That study came out in 2009, but people kept buying ginkgo supplements!
In 2010 the National Institute for Public Health and the Environment in the Netherlands decided to check into ginkgo supplements. They were investigating three health claims made by ginkgo supplement manufacturers. Specifically: improvement of blood circulation, improvement of symptoms of old age, and improvement of memory.
They evaluated 35 human intervention studies to see if those health claims could be substantiated. The final report said, "Evidence is lacking for three health claims of herbal products with G. biloba." But that's not all. They also decided to analyze 29 ginkgo supplements on the market to see what was in them. The results were bad.
"...our chemical analysis showed that 25 of the 29 sampled products did not contain the required minimum 24% standardized extract. Moreover, in most preparations the content of substances typical for G. biloba did not conform to what was declared on the label."
Most ginkgo supplements listed one thing on the label, but had something else in the pills. Even if ginkgo did provide a benefit, you would have a hard time finding supplements with the right amount of ginkgo in them.
The news continued to get worse. In October 2012 the results of a long term study using ginkgo to slow or prevent Alzheimer's disease came out. Researchers followed 2,854 participants, with half getting a twice daily dose of ginkgo and the other half getting a placebo. After more than five years, researchers concluded: "Long-term use of standardised ginkgo biloba extract in this trial did not reduce the risk of progression to Alzheimer's disease compared with placebo."
So here's where we stand. After millions of dollars spent and thousands of people given ginkgo supplements for years, it hasn't been shown to provide any benefit. Researchers are unable to show that it helps with memory, dementia, Alzheimer's, blood circulation or even "general improvements in the symptoms of old age."
There are a host of other things supplement companies claim ginkgo biloba can help with including high blood pressure, tinnitus, peripheral artery disease, macular degeneration and altitude sickness. Unfortunately there is no good evidence supporting any of those claims either.
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Food Nutr Res. 2010 Sep 30;54.
Assessment of health claims, content, and safety of herbal supplements containing Ginkgo biloba.
Hum Psychopharmacol. 2012 Nov;27(6):52733.
Is Ginkgo biloba a cognitive enhancer in healthy individuals? A meta-analysis.
Lancet Neurol. 2012 Oct;11(10):8519.
Epub 2012 Sep 6.
Longterm use of standardised Ginkgo biloba extract for the prevention of Alzheimer's disease (GuidAge): a randomised placebocontrolled trial.
Anal Bioanal Chem. 2015 Oct;407(25):773346.
Epub 2015 Aug 22.
Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatographydiode array detectorquadrupole time of flightmass spectrometry.
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