One of the most hotly marketed supplements in
Complimentary/Alternative Medicine arena is DHEA
(dehydroepiandrosterone). Just as a quick index, a Yahoo
search for DHEA turns up over three million hits, and an impressive
array of advertisements.
Many of the sites that promote the sale of DHEA state or imply that it
is a “life-extension” product.
It sure would be nice if someone would do a definitive study to show
whether or not it really can extend the life of humans.
However, such a study would be very costly to do. The main
reason for the cost is that it would require that the researchers to
enlist a lot of people, then do regular exams and blood studies on them
for the rest of their lives. You’d have to wait until
everyone died before you could do a full analysis of the results.
Another problem is that you would want to have some indication that the
conduct of the study would not expose the recipients to undue risk.
And you would want some indication that the study would be
worth doing in the first place.
Proponents might have had high hopes for the latest study on the
subject. Researchers from the Mayo Clinic and the University
of Padua recently published an article in the New England Journal of
Medicine (Volume 355:1647-1659): DHEA
in Elderly Women and DHEA or Testosterone in Elderly Men.
They studied 87 elderly men, and 57 elderly women. The men
were divided into three groups: one group got 75mg/day DHEA, one got
testosterone 5mg/day, and one got placebo. The women were
divided into two groups: one group got 50mg/day DHEA, the other got
placebo. The study ran for two years.
There are a lot of technical details to the study, but let it suffice
to say that the study appears to have been done well.
The bottom line is that they did not see any evidence for benefit, and
no evidence for harm.
An accompanying editorial by Paul M. Stewart, M.D. (Aging
and Fountain-of-Youth Hormones) explains the
background and implications. He reviews a number of recent,
valid studies. The results are largely disappointing.
The author comments:
…another “negative” study on the efficacy of DHEA
is unlikely to have much effect on its use in Western societies. Owing
to a loophole in U.S. legislation, DHEA is regarded not as a drug but,
rather, as a dietary supplement. Although DHEA was never approved as a
drug by the Food and Drug Administration (FDA), its status changed from
drug to food supplement under the Dietary Supplement Health and
Education Act of 1994. Companies that sell supplements may not claim
that the products prevent, treat, cure, mitigate, or diagnose disease,
but these guidelines are often ignored or circumvented, as appears to
be the case with many current providers of DHEA…
…Without a reversal of the current U.S. legislation, DHEA is likely
to continue to be used inappropriately, and quackery will prevail.
Furthermore, the FDA has no requirements for the composition of
supplements. As a result, commercially available DHEA preparations
contain from 0 to 150% of the amount stated on the package.
When I started to write this post, I gave it the title: Cold
Water On A Hot Product. I changed it, though,
because the results of the study are not exactly cold water.
Rather, the results show that certain endpoints (muscle mass,
bone density, insulin sensitivity, body composition) do not change.
The lack of negative health effects leaves the door open to
further study. In the editorial, Dr. Stewart even says that
“Further research focusing on the action of DHEA and its role in
patients with DHEA deficiency is certainly indicated.” (reference)
Furthermore, there is some evidence that DHEA may have a role in the
treatment of depression, as mentioned in Dehydroepiandrosterone
Monotherapy in Midlife-Onset Major and Minor Depression
(Arch Gen Psychiatry. 2005;62:154-162.)
The thing is, such specific indications for the use of DHEA would be
limited to persons with identifiable disease states. Such
uses would lead to reclassification of DHEA as a drug, which would
prevent the marketing of it as a supplement.
Anyway, the NEJM study does not entirely rule out the possibility that
DHEA may have some uses for the general population. As I
stated earlier, it does not directly assess the
possibility that it might extend life. But in the absence of
some specific confirmatory evidence, it would not make any sense to
believe that it would. If the authors had found evidence of
harm, in the absence of benefit, it would have been cold water.
Instead, it is merely tepid.