|
A 2-year trial, recently published in the October 19 issue of the New England Journal of Medicine, found that dehydroepiandrosterone (DHEA) and testosterone supplementation by elderly men and women improved participants’ bone mineral density (BMD) in certain areas of the body but did not seem to produce positive effects on body composition, physical performance, insulin sensitivity, or quality of life.1 DHEA is a naturally-occurring steroid hormone produced by the adrenal glands and an indirect precursor to the sexual hormones testosterone and estrogen. DHEA levels decline rapidly with age.
For the randomized, double-blind, placebo-controlled,trial, 29 men and 27 women were assigned low-dose sulfated DHEA tablets (75 mg per day for men and 50 mg per day for women), 27 men were given a transdermal testosterone patch (5 mg per day), and 31 men and 30 women were given placebo (either a placebo tablet with lactose as filler or a placebo patch for some men). All participants were over the age of 60. By the end of the trial, participants in the DHEA groups had significant increases in levels of sulfated DHEA and the horomone estradiol, and women had an increase in total testosterone. Men in the testosterone group had a significant increase in levels of bioavailable and total testosterone. In the treatment groups, women had a slight but significant increase in BMD of the ultradistal radius and men had a slight but significant increase in BMD in the femoral neck.
There were no major adverse effects for either treatment, and participants in the DHEA groups had significant reductions in high-density lipoprotein cholesterol levels. DHEA supplementation had no significant effects on body-composition measurements, although men who received testosterone had a slight increase in fat-free mass. Neither DHEA nor testosterone had any detectable effects on physical performance, insulin sensitivity, or quality of life.
The Council for Responsible Nutrition (CRN), a leading trade organization in the dietary supplement industry, released its own analysis of the trial as soon the study was published, as well as a statement from Andrew Shao, PhD, CRN’s vice-president of scientific and regulatory affairs (Hadesman L, e-mail, October 18, 2006). “This is the longest duration human supplementation trial confirming the safety of relatively high-dose DHEA in both men and women and we are encouraged by those results, particularly because there is a need for safe bone builders in this age group,” said Dr. Shao in his written statement. “Further, the study found small but significant increases in bone mineral density, consistent with the body of clinical trials on DHEA. The lack of other significant effects in an elderly population is surprising as that is inconsistent with the published research. This study did not look at other clinically relevant outcomes where DHEA has been shown to provide benefit, such as libido and sexual performance.”
According to CRN’s analysis, the finding of safety is the most important outcome of the study, and the trial’s authors downplayed both this and other positive outcomes of the trial.
DHEA in dietary supplement form is usually derived from the root of the Mexican wild yam (Dioscorea spp.), an herb traditionally used in folk medicine of Mexico and the southwestern United States for a variety of applications related to women’s reproduction. Partly due to its relative safety and documented benefits, DHEA was exempted from the recent legislative ban on steroid hormone-based ingredients in dietary supplements when the U.S. Congress passed the Anabolic Steroid Control Act of 2004. This act classified steroid hormone precursors such as androstenedione ("andro"), and other steroidal prohormones which have been the subject of increasing controversy, under the Controlled Substances Act.2
-Courtney Cavaliere
References
1. Nair KS, Rizza RA, O’Brien P, Dhatariya K, Short KR, Nehra A, Vittone JL, Klee GG, Basu A, Basu R, Cobelli C, Toffolo G, Man CD, Tindall DJ, Melton LJ, Smith GE, Khosla S, Jensen MD. DHEA in elderly women and DHEA or testosterone in elderly men. NEJM. 2006;355(16):1647-1659.
2. United States Senate. Anabolic Steroid Control Act of 2004 (S. 2195). October 6, 2004. Available at: http://thomas.loc.gov/cgi-bin/query/C?c108:./temp/~c108oHcasr.
|