Reduce Abdominal Fat in the Elderly with DHEA?

Summarized by Robert W. Griffith, MD
December 10, 2004

Introduction

A larger girth (due to abdominal fat) has been shown to be linked to increased risk of developing insulin resistance, diabetes, and atherosclerosis (see the first link below). Indeed, waist size is one of the factors considered in establishing the diagnosis of the metabolic syndrome, which is becoming gradually more recognized as a 'marker' for increased mortality.

Just about everyone adds inches round their middle as they get older, and some scientists have linked this to lessened production of the adrenal hormone dehydroepiandrosterone (DHEA). Blood levels of DHEA peak at about 20, and then decline quite rapidly after 25 years of age. In animals, giving DHEA reduces the accumulation of abdominal fat and protects against insulin resistance. What effect does it have in aging people? A publication in the Journal of the American Medical Association has some preliminary results.

What was done

DHEA is widely available as a dietary supplement, without a prescription. This study was done in 56 elderly people living in St Louis, Missouri. They were essentially healthy individuals, aged 65 to 78. The participants were randomly assigned to take either 50 mg of DHEA daily, at bedtime, or a matching placebo (a dummy tablet), for 6 months. This was a double-blind study - the participants and the examining health professionals didn't know which treatment was being given, DHEA or placebo.

Magnetic resonance imaging (MRI) was used to measure abdominal fat. An oral glucose tolerance test was done - blood glucose and insulin levels were measured at intervals after a 75-gram glucose drink; this allowed insulin sensitivity to be calculated. Blood lipid levels as well as levels of DHEA and other hormones (including insulin-like growth factor, or IGF-1) were determined. All these tests were done at baseline and at the end of the 6-month treatment period.

What was found

Only 52 of the 56 people entered had follow-up evaluations. Their average age was 71. There were 29 men and 27 women. Their average BMI values showed they were overweight: 27 in the placebo, and 28 in the DHEA group. There were no relevant differences between the DHE and placebo groups at baseline.

After 6 months, the DHEA subjects had lost, on average, 0.9 kg (2 pounds) while the placebo subjects had gained 0.6 kg (1.3 pounds). This effect was the same in men and women. Energy intake in the diet was unaltered, however.

DHEA therapy for 6 months produced a significant reduction in abdominal fat, both inside and outside the abdominal cavity. With DHEA there was a loss of 13 square centimeters of both types of fat, while with placebo, there was a slight increase: 2 to 3 square centimeters, on average.

The glucose tolerance test showed that the response to a glucose 'load' was unchanged by DHEA, whereas the insulin levels were significantly reduced with DHEA, so that insulin sensitivity was shown to be increased (or, in other words, insulin-resistance was diminished).

DHEA increased serum testosterone levels in women, but not in men. It increased estradiol and IGF-1 levels in both sexes. (DHEA is, in fact, a forerunner of testosterone and estrogens.)

There were no significant side effects of DHEA supplementation. In particular, prostate specific antigen (PSA) levels in the men were unchanged - 1.7 ng/mL at baseline and 1.6 ng/mL after 6 months. In the placebo group, PSA levels were 1.4 ng/mL at baseline and 1.8 ng/mL 6 months later.

What this study shows

In this study, DHEA given for 6 months at a dose of 50 mg a day produced a significant reduction in abdominal fat, and a decrease in insulin resistance. These effects reverse aging changes, to a certain extent. Perhaps DHEA can protect against the development of the metabolic syndrome, and all that it entails?

The authors of the study speculate that the effect of DHEA may be primarily on estradiol and IGF-1 production, which acts in turn on reducing abdominal fat. They argue that longer-term studies are needed to make sure that these actions on other hormones (testosterone, estradiol, IGF-1) do not have serious adverse effects. This is wise advice. It would be foolish for everyone over 65 with some increase in waist size to embark on long-term DHEA supplementation without a better idea of the potential risks involved.

Source

• Effect of DHEA on abdominal fat and insulin action in elderly women and men. DFT. Villareal, JO. Holloszy, JAMA, 2004, vol. 292, pp. 2243--2248

Related Links
Your Waistline Can Tell You a Lot About Your Health Risk
Tool: Do You Have the Metabolic Syndrome (Syndrome X)?
HealthandAge.com's Alternative Medicine: DHEA

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