A group of human volunteers get DHEA
Drs. Morales, Nelson, Nolan and Yen, from the Department of Reproductive Medicine, University of California School of Medicine, San Diego, (in La Jolla), wanted to find out the influence of DHEA supplements on middle-aged and older individuals. (We briefly mentioned this 1994 study in Chapter 1.) They were aware that aging is associated with a gradual shift from a 'young' state characterized by the building-up of muscles and tissues, called anabolism, to an 'aged' state characterized by the loss of muscle mass and strength, called catabolism (not to be confused with cannibalism).
These researchers recruited 13 men and 17 women who ranged from 40 to 70 years of age. Using a randomized, placebo-controlled, cross-over trial (the best careful and meticulously designed study for human research), they provided 50 mg of DHEA nightly for 3 months. During the study period they measured blood levels of many hormones and nutrients including androgens, lipids, and insulin, as well as body fat, libido, and sense of well-being. Within two weeks of treatment, the DHEAS levels in the bloodstreams reached those found in young adults.
A striking finding became apparent. The researchers state: "DHEA supplementation resulted in a remarkable increase in perceived physical and psychological well-being for both men and women. The subjects reported increased energy, deeper sleep, improved mood, more relaxed feeling, and an improved ability to deal with stressful situations."
Interestingly, no changes were noted in libido or body fat. Changes in blood lipids levels such as cholesterol were not significant.
Based mostly on results of this relatively short-term study, a number of people started DHEA supplements and a lot of media hype was generated. Articles appeared in various newspapers and magazines. Even Newsweek's August 7, 1995 article on melatonin had a sidebar titled, "Nature's Other Time-Stopper?"
In order to find out whether higher doses and a longer period of treatment would have a more significant effect, Drs. Yen, Morales, and Khorram (1995) gave 100 mg of DHEA to 8 men and 8 women between the ages of 50 and 65 for 6 months-- twice as long as the earlier study.
With 100 mg of DHEA on board, the serum levels of DHEAS increased several-fold in both men and women. The androgen levels doubled in the men, and quadrupled in the women. One of the eight women developed facial hair that resolved by the end of the study.
There were many biological markers assessed throughout the study. Lean body mass showed an increase in both genders, there was some increase in muscle strength of the knee, and no change was found in lipid profiles, insulin or glucose levels, nitrogen balance, bone mineral density, or basal metabolic rate. Interestingly, there was no mention of DHEA's effect on well-being as had been reported in the earlier study of 3 months.
Here are some theoretical mechanisms on how supplemental DHEA can increase lifespan, remembering, though, that as of yet there is no proof that it does so in humans:
Turning on "youth" genes in our DNA that may be shut off by low levels of DHEA in old age
Decreasing rate of heart disease by lowering cholesterol and acting as a blood thinner
Decreasing the rate of cancer
Improving insulin's function thus better regulating blood sugar levels
Balancing DHEA/cortisol ratios. As we age DHEA levels drop but cortisol levels stay relatively the same. This unbalanced ratio may have harmful consequences on blood sugar, immunity, among others.
Inhibition of glucose-6-phosphate dehydrogenase enzyme. This enzyme is involved in cancer promotion, lipid formation and production of toxic oxygen free radicals
Enhancing mood and energy. Enhanced well-being could have a mind-body effect on improving our health.