DHEA and Immune Function
DHEA levels decline 80-90% by age 70 or later. DHEA has demonstrated a striking ability to maintain immune system synchronization. Oral supplementation with low doses of DHEA in aged animals restored immunocompetence to a reasonable level within days of administration. DHEA supplementation in aged rodents resulted in almost complete restoration of immune function (Danenberg et al. 1996).
DHEA has been shown in numerous animal studies to boost immune function via several different mechanisms. Only limited human studies have been done to measure DHEA's effect on the immune system.
In one study that focused on men, scientists proposed that the oral administration of DHEA to elderly men would result in activation of their immune system: nine healthy men averaging 63 years of age were treated with a placebo for two weeks followed by 20 weeks of DHEA (50 mg a day). After two weeks on oral DHEA, serum DHEA levels increased by 3-4 times. These levels were sustained throughout the study. Compared to the placebo, DHEA administration resulted in: An increase of 20% in IGF-1. Many people are taking expensive growth hormone injections for the purpose of boosting IGF (insulin-like growth factor) levels. IGF is thought to be responsible for some of the antiaging, anabolic effects that DHEA has produced in previous human studies.
An increase of 35% in the number of monocyte immune cells.
An increase of 29% in the number of B immune cells and a 62% increase in B-cell activity.
A 40% increase in T-cell activity even though the total number of T-cells was not affected.
An increase of 50% in interleukin-2.
An increase of 22-37% in natural killer cell (NK) numbers and an increase of 45% in NK cell activity.
No adverse effects were noted with DHEA administration.
The scientists concluded: "While extended studies are required, our findings suggest potential therapeutic benefits of DHEA in immunodeficient states" (Khorram et al. 1997).
A study published in the Journal of Clinical Endocrine Metabolism showed that when old female mice were treated with DHEA, melatonin, or DHEA and melatonin, splenocytes (macrophages) were significantly higher as compared to young mice. B-cell proliferation in young and in old mice significantly increased. DHEA, melatonin, and DHEA and melatonin helped to regulate immune function in aged female mice by significantly increasing the cytokines interleukin-2 and interferon-gamma and significantly decreasing the cytokines interleukin-6 and interleukin-10, thus regulating cytokine production (Inserra et al. 1998).
Interleukin-6 (IL-6) is one of the pathogenic elements in inflammatory and age-related diseases, such as rheumatoid arthritis, osteoporosis, atherosclerosis, and late-onset B-cell neoplasia. According to a report in the June 1999 issue of the Journal of the American Geriatrics Society , "higher circulating levels of IL-6 predict disability onset in older persons." The authors suggest that IL-6 may cause a reduction in muscle strength or contribute to specific diseases such as congestive heart failure, osteoporosis, arthritis, and dementia, which cause disability (Ferrucci et al. 1999).
DHEA has consistently been shown to boost beneficial interleukin-2 and suppress damaging interleukin-6 (IL-6) levels. Interleukin-6 is overproduced in the aged, which contributes to autoimmune disease, immune dysfunction, osteoporosis, depressions in healing, breast cancer, B-cell lymphoma, and anemia. Continuous DHEA administration maintained immunocompetence in aged animals (by boosting interleukin-2 and other beneficial immune components and suppressing interleukin-6 and other detrimental immune components). Suppression of interleukin-6 with 200 mg a day of DHEA was shown to be effective against systemic lupus erythematosus (Van Vollenhoven et al. 1998).
Researchers compared levels of IL-6 in 283 subjects with a mobility or functional disability with IL-6 levels in 350 adults without a disability. The investigators found that adults in the highest third of values of IL-6 had a 76% higher rate for mobility disabilities and a 62% higher rate for inability to perform daily activities than subjects in the lowest third of values. "These data suggest that IL-6 is a global marker of impending deterioration in health status in older adults," wrote a team led by Dr. Luigi Ferrucci at the National Institute on Aging in Bethesda, MD (Ferrucci et al. 1999).
In a study in the Proceedings of the Society for Experimental Biology and Medicine, DHEA has been shown to restore normal cytokine production in immune system dysfunction induced by aging by suppressing the excessive production of cytokines (IL-6) by 75%, although increasing IL-2 secretion by nearly 50%, during a leukemia virus infection in old mice (Inserra et al. 1998).
Another study in normal healthy individuals over the age of 40 found an opposite relationship between plasma DHEA levels and the presence of detectable levels of IL-6. Studies also revealed that low doses of DHEA and DHEA-S inhibited the production of IL-6 in unstimulated human spleen cell suspension cultures and enhanced its release by cultures transferred from organs of the same tissue (James et al. 1997).
The age-related increase in circulating IL-6 levels in humans, which has been attributed to decline in DHEA production by the adrenal gland, is currently attracting attention because of its possible relevance to the etiology and management of a number of age-related clinical disorders. The potential importance of these observations and suggestions has prompted us to perform more detailed studies on the relationship between IL-6 and DHEA. Using immunoassay techniques, scientists found in normal healthy individuals over the age of 40 that low levels of plasma DHEA levels predicted levels of IL-6 (James et al. 1997).
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