April 8, 2003
The popular supplement DHEA, sometimes touted as a fountain of youth and marketed to prevent heart disease, control diabetes and lupus, enhance memory, and boost the immune system, showed little benefit in stalling memory loss in a six-month study of people with Alzheimer's disease.
Short for dehydroepiandrosterone, DHEA is sold as an anti-aging formula in health food stores and pharmacies. Sometimes called the "mother of hormones," it is secreted naturally in the body by the adrenals, small glands that sit atop the kidneys, and other tissues and is used by the body to produce estrogen and testosterone. Scientists are only now beginning to unravel the roles of these and other hormones in the development of Alzheimer's disease.
In both men and women, DHEA production declines dramatically with age. By age 70, levels of the hormone fall to as low as one twentieth of what they were at age 25. DHEA derived from wild yams and other plant sources have been touted as an anti-aging remedy for everything from lost libido to fading memory, despite scant scientific evidence that the supplement provides any benefits at all.
Fountain of Youth?
In this trial, researchers gave 58 people in the early stages of Alzheimer's disease either 50 mg of DHEA twice a day or a look-alike dummy pill. None of the patients were taking any other drugs approved for the treatment of Alzheimer's, and neither patients nor their doctors knew who was getting the DHEA. Study volunteers were then given memory tests at the start of the study, and again after three and six months. Physicians and caregivers also rated their progress.
There was a slight improvement in those taking DHEA after three months, study author Owen Wolkowitz, MD, of the University of California at San Francisco noted, but it could have been due to chance. The researchers concluded that DHEA did not lead to any improvements in memory.
David Knopman, MD, of the Mayo Clinic in Rochester, MN, who wrote an editorial accompanying the study, noted that the study was small and that many patients dropped out, making the findings hard to evaluate. Of 58 patients who started the study, only 46 completed three months, and 33 lasted the full six months. Some of them opted out in order to start taking Aricept and other conventional Alzheimer's drugs.
"DHEA alone seems unlikely to be superior to currently available [Alzheimer's drugs]," Dr. Knopman wrote. He said that larger studies are needed to evaluate its possible effectiveness, including possible tests of the hormone in combination with existing prescription medications.
In animal studies, DHEA, with or without conventional Alzheimer's drugs, appears to improve memory, but it's a long way from mice to people. Researchers have also examined levels of DHEA in people with Alzheimer's but have not yet determined what role, if any, the hormone may play in the disease.
Like all hormones, DHEA is an extremely potent substance, and taking any hormone supplement is risky business. Of particular concern is that excess DHEA has been linked in animal studies to liver cancer. In addition, because DHEA could lead to increased levels of estrogen and testosterone, it could, in theory at least, lead to an increased risk of hormone-sensitive cancers of the breast and prostate if taken long term.
In this study, patients taking DHEA had a higher incidence of such side effects as confusion, agitation, and anxiety, although those taking a dummy pill were more likely to drop out because of side effects. Anyone considering DHEA or other dietary supplements for Alzheimer's disease or memory loss should consult with their physician first.
The study was funded by the National Institute on Aging and by Neuroscience Pharma, Inc. of Montreal, a maker of DHEA supplements. It appeared in the April 8, 2003 issue of Neurology, the medical journal of the American Academy of Neurology.
By Toby Bilanow, Medical Writer, for www.ALZinfo.org. The Alzheimer’s Information Site. Reviewed by Samuel E. Gandy, M.D., Ph.D., Chairman of the Scientific Advisory Board, Fisher Center for Alzheimer's Research Foundation.