Researchers from the Department of Medicine at the Washington University School of Medicine were aware that DHEA had been shown to reduce the accumulation of abdominal visceral fat and protect against insulin resistance in animal tests. They therefore wanted to see whether the hormone could work to decrease abdominal obesity in humans and improve insulin action in elderly persons.
To this end, the scientists carried out a randomized, double-blind, placebo-controlled trial with fifty-six elderly persons (28 women and 28 men aged between 65 and 78 years), who had age-related decrease in DHEA level. The study was undertaken between June 2001 and February 2004.
Participants were randomly assigned to receive 50 mg/d of DHEA or matching placebo for six months. After which the change in visceral and subcutaneous abdominal fat was measured by magnetic resonance imaging and glucose and insulin responses to an oral glucose tolerance test (OGTT).
The researchers found that based on intention-to-treat analyses, DHEA therapy compared with placebo induced significant decreases in the visceral fat area and subcutaneous fat. Similarly, they added that the insulin area under the curve during the OGTT was significantly reduced after six months of DHEA therapy compared to placebo.
"Despite the lower insulin levels, the glucose AUC was unchanged, resulting in a significant increase in an insulin sensitivity index in response to DHEA compared with placebo," said the scientists, concluding that DHEA replacement could play a role in prevention and treatment of the metabolic syndrome associated with abdominal obesity.
This study is published in JAMA (2004;292:2243-2248).
DHEA or dehydroepiandrosterone is among the most abundant naturally occurring steroids in the blood of young humans, but its levels have been shown to peak between the ages of 20 and 30 and then decrease progressively with age.
A synthetic form of the hormone is sold over-the-counter as a dietary supplement in the US, thought to have anti-aging properties and to offer prevention against cancer and heart disease, Alzheimer's and other diseases. But scientists know relatively little about the drug and its basic biological effects on humans.
Much more research into DHEA is needed as there are fears that its hormone production could stimulate the growth of hormone-sensitive cancers, such as breast or prostate cancers. It has also been linked to build-up of cholesterol in the arteries, raising risk of heart disease.