DHEA is the hormone looked on as perhaps having the most promise as an anti-aging agent. The next few years should tell whether this hormone is the "real deal" or just another false anti-aging product.

Dehydroepiandrosterone (DHEA) has been called the "mother of all hormones." It is a steroid hormone produced and mainly secreted by the adrenal glands. DHEA is the most abundant hormone in the blood stream with levels being very high in young men, often at levels 10 times greater than any other steroid hormone. The biochemical pathway goes from cholesterol to pregnenalone, which then forms DHEA. DHEA then goes on to form the sex hormones, testosterone and estrogen. DHEA can have sulfur added to it and form DHEA-S. This is the main form found in the blood, and it stays in the blood longer than DHEA does with eventual elimination via the kidneys.

DHEA and DHEA-S levels decline with age in both males and females, with DHEA-S levels peaking at ages 20 to 24 years in men and 15 to 19 years in women. Between the ages of 40 and 70, there is significant decrease in levels and, by the time a person is 70 years old, the levels are only 20% as high as in young adults, with men having significantly higher levels than women from 20 to 69 years old. DHEAS levels remain 10% to 20% higher in men

Like many of the other hormones already discussed, the decline may or may not be an indication of disease. The role of DHEA in aging is unknown. The decrease in levels may be just part of the normal aging process or something more serious that causes premature aging. No one really knows for sure.

Animal studies have shown that DHEA reduces cholesterol levels and may increase longevity. DHEA also appears to enhance the effect of insulin, to decrease body fat, increase muscle mass, and to improve function of the immune system.

Although this is unknown for certain, declining DHEA and DHEA-S levels may be related to how long you will live. Studies on animals in regard to longevity have demonstrated that DHEA is able to increase life span. Human studies indicate that low DHEA levels are associated with increased death from all causes. The DHEA-S level in men over 50 years of age has been shown to be inversely related to death from any cause. This simply means that the lower the levels of DHEA-S, the more likely death from any cause will occur.

In one study of 290 elderly people, it was found that the risk of death was higher for men under 70 years of age who had the lowest levels of DHEA-S. No difference between death and DHEA-S levels occurred in women. In another study of 242 men between the ages of 50 and 79 years, an increase in DHEA-S levels of 100 micrograms per deciliter was associated with a 36% reduction in death from any cause.

DHEA appears to be related to the risk of cardiovascular and heart disease. Lower levels have been shown to increase the risk of cardiovascular disease in men. This has not been found in women. DHEA-S levels are lower in men with a history of heart disease than in men with no history. In addition, in males over 50, the lower levels of DHEA and DHEA-S, the greater the chance of death from cardiovascular disease.

In one study, an increase in DHEA-S levels of 100 micrograms per deciliter was associated with a 48% reduction in death from cardiovascular disease. In another study of 963 men and 1,171 women between the ages of 65 and 76 years, it was found that men who had lower DHEA-S levels had more deaths from all causes and heart disease than those men who had higher levels. However, this was not found in women. In fact, women who had higher levels of DHEA-S had the highest rates of death. The subjects were examined between 1991 and 1995 and followed until August 2000.

The exact mechanism of how DHEA and DHEA-S protect against cardiovascular disease is unknown. They appear to offer protection against coronary artery disease through inhibition of plaque progression and perhaps inhibition of platelet-derived growth factor.

Animal studies have shown that DHEA reduces cholesterol levels. Human studies have shown that taking DHEA orally can lower total and LDL cholesterol levels. In a 28-day, randomized, double-blind study in 1988 by Nestler et al. DHEA given to young men was found to decrease body fat and LDL cholesterol.

As DHEA levels decline with age, the risk of breast cancer is highest in women with the lowest levels of DHEA. This effect is observed at every age and not just in the elderly. However, the effect of DHEA therapy on cancer is unknown.

DHEA has been shown to be beneficial in regard to diabetes. Animal studies have demonstrated that there is a relationship between diabetes and obesity, which can be reversed by taking DHEA. DHEA appears to increase the sensitivity of insulin and enhances its effectiveness.

It also appears to decrease the percentage of body fat and increase the percentage of muscle mass. DHEA taken at100 mg per day resulted in increased insulin-like growth factor, which resulted in increases of lean body mass in men and women. Knee muscle strength also increased in males. The subjects were eight men and eight women between the ages of 50 and 65, taking either DHEA or placebo for six months.

It appears that DHEA can improve immune system function. In a placebo controlled study of 11 postmenopausal women with an average age of 56, those taking 50 mg of DHEA for three weeks showed an increase in both the number and activity of natural killer cells. (Remember natural killer cells are cells of the immune system that fight cancer). No side effects were reported. It is also thought that DHEA can improve the effectiveness of vaccinations in the elderly.

DHEA replacement in adrenal insufficiency improves overall well-being, mood, and sexuality. The researcher Morales administered a replacement dose of DHEA in 13 men and 17 women between the ages of 40 and 70 in a randomized, placebo-controlled, cross-over design. The oral dose of DHEA given was 50 mg over a period of six months. After only two weeks, serum levels of DHEA and DHEA-S were restored to those found in young adults. There was an increase in perceived physical and psychological well-being for both men (67%) and women (84%). No changes in libido, liver, or thyroid function were reported.

There is some concern about taking DHEA in regard to cancer. There appears to be a positive relationship between DHEA and breast cancer risk. However, this risk seems to be what is termed "non-significant." It does not appear that increased levels of DHEA and DHEA-S decrease breast cancer risk. Taking DHEA may increase levels of the hormone insulin-like growth factor-1, which has been shown to increase the risk of breast and prostate cancer. Therefore, taking DHEA may aggravate existing prostate and breast conditions. In addition, if someone has a family or personal history of a tumor that is related to hormones, such as breast cancer or prostate cancer, taking DHEA may increase the risk. It may also negatively affect women who have cancers of the reproductive tract. Therefore, any person who has any of these conditions should not take DHEA supplements.

DHEA is available over the counter and should only be taken when DHEA levels are low and if normal levels of prostate antigen are present. I cannot recommend any specific dose at this time; however, research has shown that DHEA given daily at an oral dose of 25 or 50 mg for 8 days was found to be safe in 24 healthy aging men and women. If a person does take DHEA, he should also increase his intake of the antioxidants vitamin C, vitamin E, and selenium. Do not take any DHEA supplement without the advice of an expert in this area.

Although there is very little data, it appears that nutrition may affect DHEA-S levels. In rhesus monkeys, calorie restriction slows the decline in serum DHEA-S levels. Because of this, some researchers believe that nutritional intervention can affect aging; however additional study is necessary before any definitive conclusions can be made.

This is thought to be the first evidence that nutrition can affect DHEA-S levels and perhaps aging.