Ginkgo does not prevent dementia, or “I can’t remember what NCCAM is good for”

ResearchBlogging.orgHere’s a question for you: is there, or should there be, any difference between studies of “alternative” and non-alternative medicine? I’ve argued before that there is no such thing as alternative medicine. So why do we need a separate agency to study “alternative” medicine? The National Center for Complementary and Alternative Medicine seems to be just such an agency. For example, the latest study of Gingko biloba for the prevention of dementia could have been funded by other agencies, such as NIMH. Why NCCAM?

First a glance at the study in question. In the introduction, the authors make their case for doing the study in the first place. They write of some in vitro studies of Gingko that show a possible justification, and mention the popularity of the substance. They also quote a number of studies that have looked at Gingko in people who already have dementia, the results of which were not good.

I have a bit of trouble with this. They admit that there is no real evidence that Gingko does anything. Scientifically, there isn’t very good justification to study the issue. But economically, there may be. If it is true that (in their confusing phrase), “In the United States, worldwide sales of G biloba exceed $249 million annually,” then it may be worth doing a study simply to debunk the myth that Gingko is anything other than a scam. The study was what I would characterize as an unqualified success. Gingko showed no efficacy in preventing Alzheimer’s-type dementia.

This seems to be a pattern at NCCAM, which on the outside seems to promote CAM, but ends up acting as a de facto “debunking” agency.

A quick glance at NCCAM’s front page:

    “Ginkgo Evaluation of Memory (GEM) Study Fails To Show Benefit in Preventing Dementia in the Elderly”
    “CAM and Hepatitis C: A Focus on Herbal Supplements ‘No CAM treatment has yet been proven effective for treating hepatitis C or its complications.'”
    Selenium and Vitamin E in Prostate Cancer Prevention Study, ‘selenium and vitamin E supplements, taken either alone or together, did not prevent prostate cancer.'”

Get the picture? It turns out that when you fund a government agency to look at the benefits of snake oil, the stuff is still snake oil.

i-55807ed94dc4a25adc79aa769160453a-551px-Gingko2_phixr.jpgNow, I’ve always thought negative studies were useful; they show the success of the scientific method, and it is too easy for publication bias to make them invisible. But it seems like we have a whole agency devoted to the investigation of improbable medical claims—and all the studies are negative.

NCCAM would seem to be a “Tooth Fairy” agency—to quote Dr. Harriet Hall:

You could measure how much money the Tooth Fairy leaves under the pillow, whether she leaves more cash for the first or last tooth, whether the payoff is greater if you leave the tooth in a plastic baggie versus wrapped in Kleenex. You can get all kinds of good data that is reproducible and statistically significant. Yes, you have learned something. But you haven’t learned what you think you’ve learned, because you haven’t bothered to establish whether the Tooth Fairy really exists.

Here’s NCCAM’s stated mission:

    Explore complementary and alternative healing practices in the context of rigorous science.
    Train complementary and alternative medicine researchers.
    Disseminate authoritative information to the public and professionals.

Number one seems fine, but why a separate agency? Number two seems non-sensical—why would researchers need specific training in CAM? Number three is admirable.

How are they doing? If their headlines are any indication, they’ve figured out what we already knew—the tooth fairy may not exist, but you can still design a study to find her favorite color.


Steven T. DeKosky, MD; Jeff D. Williamson, MD, MHS; Annette L. Fitzpatrick, PhD; Richard A. Kronmal, PhD; Diane G. Ives, MPH; Judith A. Saxton, MD; Oscar L. Lopez, MD; Gregory Burke, MD; Michelle C. Carlson, PhD; Linda P. Fried, MD, MPH; Lewis H. Kuller (2008). Ginkgo biloba for Prevention of Dementia The Journal of the American Medical Association, 300 (19), 2253-2262