May 12 2009
Taking a DHEA supplement combined with vitamin D and calcium can significantly improve spinal bone density in older women, according to a new study from a Saint Louis University scientist and his colleagues at Washington University.
"The results of our study are very promising. Similar studies have demonstrated much smaller benefits for bone than we found. However, calcium and vitamin D deficiencies, which are present in half of older adults, may have prevented DHEA from improving bone density in the earlier studies," said Edward Weiss, Ph.D., associate professor of nutrition and dietetics at Saint Louis University's Doisy College of Health Sciences and lead author of the study.
"In our study, we supplemented all participants with calcium and vitamin D to ensure that deficiencies were not present. This may explain why our study showed more favorable effects on bone density."
DHEA (dehydroepiandrosterone), a naturally occurring steroid hormone produced in the adrenal gland, gonads and brain, decreases with age. According to Weiss, low DHEA concentration has been associated with low bone density, which lead researchers to question whether restoring DHEA levels could improve or preserve bone health.
The two-year study divided men and women, ages 65 to 75 years old, into two groups. The first group received the DHEA supplement, vitamin D and calcium for two years. The control group received a placebo, vitamin D and calcium for the first year and then received the DHEA supplement the second year in place of the placebo.
The effects of the treatment differed for men and women. After the first year, women in the test group experienced an approximate 2 percent increase in bone density, while women in the control group did not see an increase. After the second year when both groups took the DHEA supplement, women in the test group experienced an additional 2 percent increase for a total of approximately 4 percent, while women who switched from placebo to DHEA also experienced an approximate 2 percent increase.
The same treatment, however, did not offer similar benefits for older men. Instead, men in both the test and control groups experienced a 1 to 2 percent increase in spinal bone density. According to researchers, the results suggest that vitamin D and calcium supplements, which were give to both groups, could be responsible for the increase in bone density.
The results of the study are promising for older women. According to Weiss, patients who achieve similar increases of 2 to 4 percent in spinal bone density with the help of medication experience a 30 to 50 percent reduction in risk of spine fractures.
Further, researchers say that the increase in spinal bone density experienced by women in the test group who took DHEA for two years, is at least as effective as other current therapies including estrogen and bisphosphonates, a class of prescription drugs that increases bone density.
However, like other therapies, the benefits of DHEA supplements were limited to spinal bone density. Neither men nor women experienced an improvement in hip bone density. Weiss says the hip may respond more slowly to bone-enhancing therapies than the spine, thus requiring more time to see a beneficial effect. More research is needed though.
"In addition to its beneficial effects on bone, DHEA replacement may have other benefits including improvements in risk factors for diabetes and heart disease, improvements in immune function, and improvements in psychological health," Weiss said.
While the research findings are promising, Weiss says that people should consult with their doctor before taking DHEA, which is an over-the-counter dietary supplement.
"Although DHEA is generally considered safe for consumption at 50 mg per day, it increases estrogen and testosterone levels which in turn could increase cancer risk," Weiss explained. "Therefore, DHEA supplementation should be avoided in men and women who have had cancer or who have a strong family history of cancer until further research can establish whether or not it is safe for these individuals."
The study was funded with grants from the NIH, NIH General Clinical Research Center and NIH Clinical Nutrition Research Unit. Findings were published in the May 2009 issue of the American Journal of Clinical Nutrition.
Study coauthors include Krupa Shah, Luigi Fontana, Charles P. Lambert, John O. Holloszy and Dennis Villareal.