Dhea Danger | Dhea Benefits | Dhea
Dhea Danger And Dhea Benefits: Is DHEA really, as some suggest, the fountain of youth in a bottle?
What is the most popular nutritional supplement ingested by runners right now? Well, if we forget about antioxidants for a moment, the most beloved nutritional add-on would have to be DHEA. In case you're among the few out-of-fashion types who haven't heard about the stuff, DHEA is not a food preservative or a drug-enforcement agency; it's actually dehydroepian-drosterone, a steroid chemical which occurs naturally in your body but which - somewhat paradoxically - you are also free to buy at an extremely high price at your local 'health-food' shop.
In the San Diego investigation, subjects didn't have to take DHEA pills, because - as mentioned - DHEA is a natural steroid chemical found in the blood and tissues of all human beings. Produced from cholesterol in the adrenal glands, it can reach a blood concentration which is actually 10 times greater than the level of any other steroid hormone. Its exact physiological mechanism is still unclear (sell the stuff anyway!), but it's thought that DHEA can be used to either manufacture testosterone, the key male sex hormone, or oestrogen, the prime female hormone. This means that DHEA could play a role in all the actions which we associate with sex hormones, including the maintenance of sexual characteristics, growth, and the repair of muscles and connective tissues.
Decline and fall
Although our DHEA levels are high when we're young, they decline steadily with ageing, dropping to about 10 to 20 per cent of youthful, 'normal' values when we reach the ripe-old age of 70. Since physical maladies accelerate in frequency in parallel with DHEA's decline, some scientists have speculated that DHEA drop-offs may actually be responsible for some age-related illnesses.
More specifically, since the late 1950s medical researchers have speculated that low DHEA levels might be a risk factor for atherosclerosis. In the 1986 San Diego study, researchers pursued that possibility by assembling a group of 242 men aged 50 to 79, measuring their DHEA concentrations, and then monitoring their illnesses over a 12-year period. 76 of the 242 men died during the 12-year follow-up, and the investigators found that having low DHEA levels (below about 140 micrograms per decilitre, which represented the 50th percentile) increased a man's risk of death from heart disease by more than three times. In contrast, upswings in DHEA of about 100 micrograms per decilitre reduced mortality from any cause by 36 per cent and decreased the cardiovascular-disease death rate by 48 per cent.
But such upswings were not exactly easy to come by. In fact, the San Diego scientists learned that DHEA levels tend to dive by about 6.5 micrograms for each year of life, making the passing of the troublesome 140-microgram marker almost inevitable by the age of 65 or so. Of course, the mere fact that DHEA concentrations declined in synchrony with increases in heart-attack death rates doesn't mean that low DHEA caused cardiovascular problems. In addition, the San Diego researchers were unable to determine the exact mechanism behind DHEA's potentially protective action, although they suggested an interesting possibility: a lack of DHEA might stimulate excess production of fat by the liver, which would have an artery-clogging effect.
Can it help improve your body composition?
The link between DHEA and cardiac health is an intriguing one, but it still doesn't explain why DHEA is so popular among athletes. The latter phenomenon is partly marketing, with scads of ads and articles in popular magazines referring to DHEA as a 'hormonal superstar'. The general tenor of such DHEA boosterism is that the chemical rejuvenates the body, upgrades overall energy, and promotes faster recovery from physical stress. Although there's little evidence that DHEA actually does any of these things, another reason for the compound's commercial success is that scientific research has linked the steroid with improvements in body composition and the trimming of excess corporeal fat.
The interest in DHEA as an anti-fat agent actually goes back to the 1970s, when researchers studying obesity found that mice could eat quantities of food which would ordinarily make them quite fat and yet stay fairly sleek and slim, as long as they were ingesting rather large doses of DHEA. An interesting aspect of this research was that DHEA-fed mice also seemed to have a lower risk of breast cancer. Follow-up studies showed that DHEA wasn't just for mice; it also improved body composition in rats and dogs.
This research was eventually extended to humans, and at first the results seemed pretty positive. In a study carried out at the Medical College of Virginia in 1988, five 'normal' men weighing about 170 pounds with 16 per cent body fat embarked on a four-week programme of DHEA supplementation during which they took in 1600 mg of DHEA per day, a relatively hefty dose (supporters of DHEA as a 'hormonal superstar' often call for intakes of only 50 to 100 mg per day, for reasons we'll explain in a minute). During the same time period, five other men consumed only a placebo.
The research demonstrated that DHEA intake actually produced an upsurge in DHEA blood levels (this may seem automatic, but some sceptics had argued that DHEA would be broken down in the digestive tract before it got to the blood). The increases in blood DHEA were pretty substantial, ranging from 2.5- to 3.5-fold.
But the real news was that the DHEA diners achieved big improvements in body composition. Their average percent body fat decreased by 31 per cent (from about 16 to 11 per cent), but body weight did not change, suggesting that the reduction in fat was coupled with an increase in muscle mass. Another positive change was that total cholesterol dropped by 7 per cent, with almost all of the fall accounted for by low density lipoprotein (aka 'bad' cholesterol). This effect might have been at least partially responsible for the reduced cardiovascular mortality among high-DHEA men in the San Diego study mentioned earlier.
A miracle drug?
Thus it seemed that DHEA might really be a 'miracle drug', heightening muscle mass, lowering body fat, and reducing the risk of cardiovascular troubles. The only clouds on the DHEA horizon were that only five men actually used DHEA in the Virginia study, too small a number to take to the bank - and that follow-up studies failed to show similar benefits for DHEA.
For example, in very similar research carried out a few years later at the University of Rochester, eight healthy men took the same quantity of DHEA (1600 mg per day) for four weeks. Again, the upswings in blood DHEA were substantial (about nine-fold), but this time there were no improvements in body composition or reductions in total cholesterol. The Rochester investigators also found that DHEA did not raise metabolic rate, as some researchers had suggested, nor did it increase protein synthesis - an effect which should be present if DHEA actually helps increase muscle mass.
Thus, there's very little evidence to suggest that DHEA actually makes humans more muscular and less fat, despite the claims of DHEA supplement makers. The idea that DHEA can upgrade body composition takes a further hit when it's realised that most of the mouse and rat studies which linked DHEA with greater leanness involved genetically unusual animals. There's little reason to expect that the metabolism of a genetically altered mouse would perfectly mimic what happens inside the human body, especially since mice don't even synthesise DHEA on their own (to get it inside their bodies, you have to inject it or put it in their food).
What about older athletes?
Both of the key DHEA studies mentioned above involved fairly young people (average age was 24 in the Virginia research and 26 in the Rochester study), so it has been suggested that DHEA supplements would work much better in older subjects who have fairly low natural DHEA levels. In an often-cited study carried out by Dr. Samuel Yen and colleagues from the University of California at San Diego, 17 women and 13 men who averaged 54 years of age took 50 mg of DHEA orally each night before bedtime for three months. Again, serum DHEA rose significantly, reaching the levels usually observed in young people within two weeks. However, the DHEA treatment had no effect at all on body composition or carbohydrate metabolism, although it did increase insulin-like growth factor, a chemical which stimulates cell growth, by about 10 per cent.
In this study, the major effect of DHEA was on the subjects' senses of well being: about 82 per cent of the women and 67 per cent of the men reported an improved quality of sleep, greater energy, and an increased ability to handle stress. These findings may seem surprising, but research has determined that DHEA can act directly on nerve cells in the brain, increasing or decreasing their responsiveness to various neurotransmitters (chemicals which carry messages from one nerve cell to another). Since DHEA can be so readily converted to sex hormones, the San Diego researchers were interested in the effect it might have on sexual behaviour, but no changes in libido or sexual activity were observed in the study (one woman did detect an increase in facial hair, however).
In a second investigation carried out with postmenopausal women who were about 56 years of age, 50 mg of daily DHEA did improve immune-system functioning. And in a third study with older people, 100 mg of DHEA per day boosted insulin-like growth factor, heightened lean body mass, and enhanced muscle strength at the knee.
Thus, it seems that DHEA seems to work more effectively in older individuals, compared to young upstarts. This makes sense, since most young people already have fairly decent DHEA concentrations. If your adrenal glands are already pumping out goodly quantities of the steroid, there is really no reason to take the stuff as a supplement.
True, some physiologists have pointed out that many fairly young, high-mileage runners are a bit like old people, since their voluminous training tends to drive down sex-hormone levels. DHEA proponents proclaim that DHEA supplements can truly help such individuals by bringing DHEA and testosterone or oestrogen up to snuff, which would promote better recovery between training sessions, but there's no scientific evidence at all to support this idea.
As you have already surmised, a great deal more scientific work needs to be carried out with DHEA before a full understanding of its effects is reached. However, don't expect this research to take place soon. To put it bluntly, the pharmaceutical industry will be very reluctant to financially support DHEA studies, since DHEA is a molecule that can not be patented and therefore can not bring substantial financial bonuses to any one company.
The bottom line is that if you decide to take DHEA, there will be a guinea pig involved, and that experimental animal will be you. Walking into a nutritional supplement shop, purchasing a bottle of DHEA, and then dosing yourself with the stuff without knowing your own DHEA concentration is pure insanity, because there are risks associated with DHEA supplementation: although research has indicated that high DHEA may be protective against breast cancer in premenopausal women, studies suggest that DHEA may increase the risk of liver cancer in both sexes, ovarian cancer in women, and prostate tumours in men. Women who take 100 mg a day or more may also notice masculinising effects, and the long-term side effects of DHEA supplementation are unknown.
DHEA is simply not a chemical that you want to cavalierly throw into your body; you shouldn't take it unless your serum levels are low and you're under the supervision of your doctor.
And runners and other endurance athletes shouldn't forget that not a single scientific study has linked DHEA supplementation with improved recovery from workouts or upgraded performances in any athletic pursuit. Under the supervision of a doctor, DHEA supplements might be beneficial for individuals over the age of 50 (about 50 mg of DHEA per day are enough to raise blood quantities of DHEA to youthful levels), but scientific research has yet to identify its benefits for younger people or athletes.
Dhea Danger and Benefits
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