Friday, September 7, 2012

Ginkgo Biloba: Another Supplement Bites The Dust--Almost

One of the biggest fears among seniors is the development of dementia, particularly Alzheimer's, which comprises about 60% of dementia cases.  According to currently available statistics, about 1 out of 7 seniors over 65 develops dementia, as do about 3 out of 8 above 85.

Nevertheless, the moment many seniors experience any memory problems, the first thing they worry about is if they are developing dementia. On this point, I turn to my favorite quote source Mark Twain, who once wrote and I paraphrase, "I have spent most of my time worrying about things that never happened."  Clearly in most cases, dementia begins with memory problems, but not every memory problem is dementia, and forgetting something once in a while is not necessarily a sign of dementia. I write this not to discourage proper follow-up of increasing or sudden onset of significant memory problems, but to caution sanity when your mind doesn't seem to work as well as it once did and you forget a thing or two. There are many reasons one may forget something, the simplest being distraction and the most complicated being more than dementia.

Nevertheless, the business of helping people deal with memory issues is thriving.  There are books, games, programs, specialized exercise equipment, medical foods, and of course supplements that promise improvement in memory if you just use them. One of the foremost among them is Ginkgo Biloba. Skipping over the detailed specifics of its origins, it is best summarized as an extract of trees that typically grow in China. This extract has been purported to be used by the Chinese for centuries and studied extensively. Nevertheless, there is quite a bit of debate regarding its effectiveness in treating memory problems and preventing Alzheimer's.  European studies have shown more benefits than American studies for memory help.

One of the biggest problems with many medical studies is that they are paid for by the manufacturer of the product who controls what gets data released and this often creates a conflict of interest for the researcher. Therefore, one hardly ever sees a negative study paid for by the manufacturer.  Imagine my surprise and delight to learn about a new study about ginkgo biloba that was paid for by Ipsen, the producer of ginkgo biloba extract that had negative findings. And by negative, I mean the product did not do what the researchers had hoped it would do--stop the progression of Alzheimer's.

Here are the results of the study copied verbatim from the study itself:


Between March, 2002, and November, 2004, we enrolled and randomly allocated 2854 participants, of whom 1406 received at least one dose of ginkgo biloba extract and 1414 received at least one dose of placebo. By 5 years, 61 participants in the ginkgo group had been diagnosed with probable Alzheimer's disease (1·2 cases per 100 person-years) compared with 73 participants in the placebo group (1·4 cases per 100 person-years; hazard ratio [HR] 0·84, 95% CI 0·60—1·18; p=0·306), but the risk was not proportional over time. Incidence of adverse events was much the same between groups. 76 participants in the ginkgo group died compared with 82 participants in the placebo group (0·94, 0·69—1·28; p=0·68). 65 participants in the ginkgo group had a stroke compared with 60 participants in the placebo group (risk ratio 1·12, 95% CI 0·77—1·63; p=0·57). Incidence of other haemorrhagic or cardiovascular events also did not differ between groups.


Long-term use of standardized ginkgo biloba extract in this trial did not reduce the risk of progression to Alzheimer's disease compared with placebo.

This study performed by Bruno Vellas, MD, of Hopital Casselardit in Toulouse, France, and colleagues was reported in The Lancet Neurology.
According to the researchers, "Ginkgo has been used in some countries by patients with cognitive disorders, and its plausible mechanisms of action for brain benefits include antioxidant effects and potential inhibition of caspase-3 activation and amyloid-beta aggregation."

Quoting, furthermore, the researchers noted, "Yet several studies -- including the Ginkgo Evaluation of Memory trial reported in 2008 -- haven't been able to demonstrate that the plant extract can prevent dementia. Indeed, the entire field of prevention of Alzheimer's disease is lacking, with little effects seen for various therapies including hormone replacement therapy, NSAIDs, vitamins, and cholinesterase inhibitors."

According to a Columbia University professor, this was a well constructed, if imperfect study. What makes it most noteworthy is that it was paid for by the manufacturer and did not get the desired results. That makes this study more reliable in my mind.

So there you have it. Another staple of the supplement industry bites the dust, at least as far as for Alzheimer's prevention value. It may still have some value in short term memory help, but that's a topic for another day.

1 comment:

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