Evidence mounts against DHEA use in treating cognitive decline

May 21 2008

DHEA supplements are widely-available and touted as a preventive agent for many chronic diseases. A new study published in Journal of the American Geriatrics Society finds no evidence of a beneficial effect of DHEA supplements on cognitive function in healthy older adults. The researchers believe that based on their study, DHEA supplements should not be recommended for enhancement of cognitive function or well-being in the general population.

DHEA is a naturally-occurring hormone in the human body that serves as a precursor to male and female sex steroid hormones (androgens and estrogens). Levels of DHEA peak between the ages of 20 and 30 and decline with age. By age 70, DHEA levels are only about 20 percent of what they were in young adulthood.

The research is the first long-term study (1-year in length) to examine the effects of supplementation in a healthy sample of older men and women. The study included 110 men and 115 women aged 55-85. They received either daily 50 mg doses of DHEA or a similar looking placebo pill for 1 year. Six cognitive function tests were given and measures of depression, perceptions of physical and emotional health, life satisfaction and sexual function were recorded at the beginning of the study and again after 12 months.

"We found that, although youthful levels of DHEA were restored in the group on treatment, the DHEA supplements had no benefits for cognitive function in these healthy older adults," says Donna Kritz-Silverstein, lead author of the study. There were also no differences seen between those taking DHEA and those taking placebo in any of quality-of-life measures.

Previous clinical trials examining the effects of DHEA supplementation on cognitive function and quality-of-life have inconsistent results, with some showing positive effects and others showing no effect. However, these trials used small sample sizes, were of short duration (generally 2 weeks to 4 months) and did not include older men and women who were at an age when memory loss and cognitive impairment become more apparent. Also, unlike the participants in the majority of previous studies, the participants in this study were not selected for lower levels of DHEA, meaning the results reflect what would be found in the general population.