nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
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Monday, December 1, 2008

FIRST IN A SERIES OF SPECIAL ISSUES: GINKGO BILOBA

There were several studies published in the last two weeks that are fascinating, for the results… and the Object Lessons they contain about science and health policy.  I decided to alter the format and write these up as a series of single topic newsletters.  The subjects are Ginkgo biloba, universal healthcare world-wide, and silicone breast implants.  You’ll be surprised by what I found.

Today’s subject is Ginkgo biloba and dementia.  Note that “dementia” is a general term, and Alzheimer’s accounts for over 90% of all dementias of the elderly.

“How much unlike art thou to Dementia
How much unlike my hopes and my deservings!” …(The Merchant of Venice, medical edition)

Talk to people about Ginkgo biloba and you find that most people think it improves thinking and memory.  A smaller percentage isn’t sure and wouldn’t take it, but think it’s OK to try…what could it hurt?  Few are wary of it.  Biochemical studies have shown promise that it reduces neuronal cell death and other beneficial effects --in the lab, not in humans.  Worldwide sales of Ginkgo biloba products, out of the US alone, exceed $249 million annually, despite analyses that show that these products contain variable amounts of the active ingredients, and sometimes contain adulterated material (lead, in one case).

A large randomized controlled trial of over 3000 people 75 years old or older was recently published.  The subjects were followed for over 6 years, while they took a standard dose of G biloba versus placebo.  The people were interesting because there were about the same number of men as women, from all over the country, but were 95% ethnically white.  Although most performed normally on a dozen cognitive tests initially, 15% had mild cognitive impairment (MCI).  All the tests and diagnostic criteria were ones that are considered standard.  They got re-tested about every six months, while taking placebo or a formulation of G biloba that is used in many commercial products, and at the maximum dose used clinically.  This was a very well-designed study and the largest ever.  (Reference: Ginkgo biloba for Prevention of Dementia, A Randomized Controlled Trial by Steven T. DeKosky, MD. et al, JAMA. 2008;300(19):2253-2262)

 

All that is very dull stuff, but what did they find?

1.       During the study 523 people developed dementia.

2.       More people developed dementia, including Alzheimer’s, after taking G biloba, than those people taking placebo, but the results were not statistically significant. (277 v 246, p = 0.21)

3.       There was no influence of age, gender, genetic susceptibility, or MCI on the results.

4.       Those individuals who had cardiovascular disease (CVD) from the beginning were more likely to become demented after taking G biloba, and this was statistically significant, if small in number (p = 0.006).

5.       Twice as many people taking G biloba experienced hemorrhagic strokes than those taking placebo, but this was not statistically significant.  An even larger study is needed to decide this.

Caveats:  Dementia is not the same as mental alertness in normal people; taking G biloba may make you feel like it’s helping your alertness and recall, but it’s clear that it doesn’t slow down the development of dementia.  Also, it’s possible that if you took G biloba for 20 years, or all your life, it might be different.  However, the trend after six years is, if anything, in the opposite direction.  AND, don’t forget those pesky strokes…

So, the bottom line is not surprising:  a product containing many different, and uninvestigated, compounds may be harmful.  This includes most herbals and alternative medicines.  We’re finding out new things every day about their constituents.

As the editor wrote,

“The potential adverse effects of G biloba extract illustrate why it is untenable to recommend a drug or nutraceutical in the absence of efficacy evidence simply because it could possibly help and initially appears harmless.”  (Object Lesson No. 1)

By the way, you may know about another herbal, Saw Palmetto—some men take it for “prostate health,” whatever that means.  I read a study showing that it contains a compound with estrogenic activity…and, you guessed it, some men experience breast enlargement.  Not something every male looks forward to.

I don’t take any herbals, and don’t recommend any of them.  If you want something that’s organic and healthy, eat oatmeal.

As I’ve said to some of you, being “natural” is no assurance of being beneficial, or even harmless:  digitalis is natural, but so is hemlock.

Doc D

Opinions are entirely my own.

 

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