DHEA) and Androstenedione Has Minimal Effect on Immune Function in Middle-Aged Men
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Original Research Ingestion of a Dietary Supplement Containing Dehydroepiandrosterone (DHEA) and Androstenedione Has Minimal Effect on Immune Function in Middle-Aged Men Marian L. Kohut, PhD, James R. Thompson, MS, Jeff Campbell, BA, Greg A. Brown, MS, Matthew D. Vukovich, PhD, Dave A. Jackson, MS, Doug S. King, PhD Department of Health and Human Performance, Iowa State University, Ames, Iowa Key words: aging, cytokines, lymphocyte, hormones, androstenedione, DHEA Objective: This study investigated the effects of four weeks of intake of a supplement containing dehydro- epiandrosterone (DHEA), androstenedione and herbal extracts on immune function in middle-aged men. Design: Subjects consumed either an oral placebo or an oral supplement for four weeks. The supplement contained a total daily dose of 150 mg DHEA, 300 mg androstenedione, 750 mg Tribulus terrestris, 625 mg chrysin, 300 mg indole-3-carbinol and 540 mg saw palmetto. Measurements: Peripheral blood mononuclear cells were used to assess phytohemagglutinin(PHA)-induced lymphocyte proliferation and cytokine production. The cytokines measured were interleukin (IL)-2, IL-4, IL-10, IL-1, and interferon (IFN)-␥. Serum free testosterone, androstenedione, estradiol, dihydrotestosterone (DHT) were also measured. Results: The supplement significantly increased serum levels of androstenedione, free testosterone, estradiol and DHT during week 1 to week 4. Supplement intake did not affect LPS or ConA proliferation and had minimal effect on PHA-induced proliferation. LPS-induced production of IL-1beta, and PHA-induced IL-2, IL-4, IL-10, or IFN-gamma production was not altered by the supplement. The addition of the same supplement, DHEA or androstenedione alone to lymphocyte cultures in vitro did not alter lymphocyte proliferation, IL-2, IL-10, or IFN-␥, but did increase IL-4. In addition, serum HDL-C concentration significantly declined. Conclusion: These findings suggest that, although chronic intake of a complex dietary supplement contain- ing DHEA, androstenedione and herbal extracts increases serum androgen levels, it has minimal effect on immune function in middle-aged men. INTRODUCTION nutritional supplements containing different combinations of these androgenic steroid hormones are sold, the potential ef- The plasma concentration of several androgenic steroid fects of these supplements on immune function have not been hormones declines with advancing age [1]; therefore, the older characterized. adult population may consume supplements containing andro- Immune function may decline with age, and the results from genic steroids in an effort to reverse age-associated changes several studies suggest that supplementation with the steroid such as the decrease in immune function. In addition, strength/ dehydroepiandrosterone (DHEA) may modify the age-related power athletes may use these substances in an attempt to changes of immune response. It is well documented that the enhance performance. Various combinations of herbal extracts production of the cytokine interleukin-2 (IL-2) declines with have been added to the androgenic steroid-containing supple- age [2]. It has been suggested that a dysregulation in cytokine ments that are sold over the counter, in an attempt to maximize balance (reduced T helper type 1 (Th1) cytokines, increased T the “androgenic effect” of these dietary supplements. Although helper type 2 (Th2) cytokines) may also accompany the aging Address correspondence to: Marian L. Kohut, Ph.D., Department of Health and Human Performance, Iowa State University, 235 Forker Building, Ames IA 50011. E-mail: [email protected]. Journal of the American College of Nutrition, Vol. 22, No. 5, 363–371 (2003) Published by the American College of Nutrition 363 DHEA, Androstenedione and Immunity process [2–5]. IL-2 and interferon-␥ (IFN-␥) are Th1 cytokines preventing conversion to DHT [22], indole-3-carbinol and that drive cell-mediated immune responses, whereas Th2 cyto- chrysin, which prevent aromatization of androgens [23,24], and kines promote humoral-mediated immunity. The age-related Tribulus terrestris, suggested to increase serum lutenizing hor- dysregulation in Th1/Th2 cytokine balance may contribute to mone, although this claim has not been verified in a controlled an impaired ability to defend against infection [3]. Studies trial. These herbal extracts are not known to exhibit significant using animal models have demonstrated that one of the steroids immunomodulatory properties. The purpose of this study was contained in the over-the-counter “androgenic dietary supple- to investigate the immunological effects of four weeks of oral ments,” dehydroepiandrosterone (DHEA), may reverse the age- ingestion of a supplement containing DHEA, androstenedione, related decline of immune function and provide protection from saw palmetto, Tribulus terrestris, chrysin and indole-3-carbinol infection [6]. Aged mice treated with DHEA exhibit enhanced in middle-aged men. Serum levels of several steroid hormones interleukin (IL)-2 and interferon (IFN)-␥ production with no were also monitored. In addition, blood samples from middle- effect on IL-4 or IL-10, perhaps reversing the age-associated aged men were collected to assess the in vitro effects of the change in Th1/Th2 cytokine balance [4,5]. supplement and its androgenic components. In addition to its potential effect on cytokines, other studies have shown that the same component, DHEA, contained in “androgenic dietary supplements” has a protective effect METHODS against infection with numerous pathogens (M. tuberculosis, West Nile virus, Herpes simplex type, Coxsackie virus) in mice Subjects [7–9]. However, it is important to note that lifelong treatment Sixteen healthy men between the ages of 50 and 59 not with DHEA did not reverse immunosenescence or enhance taking medications or dietary supplements were recruited for resistance to infection in rodents [10]. Fewer human studies this double-blind study. Written informed consent was obtained exist, and there is limited evidence suggesting that DHEA can from each participant, and the protocol was approved by the reverse immunosenescence. In several trials, oral DHEA ad- Iowa State University Human Subjects Review Board. Each ministration did not significantly improve the immune response subject completed a medical history, to eliminate subjects with to influenza immunization [11–13]. The effect of “androgenic known chronic disease, and a dietary evaluation. Subjects were dietary supplements” on overall immune function is not well randomly assigned to consume either a rice flour oral placebo studied in humans. Based on two reports of healthy, older (n ϭ 8) or an oral dose of the dietary supplement (n ϭ 8) for adults, some aspects of immune function may be enhanced by 28 days. The supplement contained 150 mg DHEA, 300 mg DHEA treatment, whereas others show no effect or are inhib- androstenedione, 750 mg Tribulus terrestris, 625 mg chrysin, ited [14,15]. The effect of a complex “androgenic dietary 300 mg indole-3-carbinol and 540 mg saw palmetto. The sup- supplement” on immune responsiveness has not been studied in plement was consumed in three equal doses taken before 0900, humans to our knowledge. at 1500 and before bedtime. The supplement was supplied by Other weak androgenic steroids include dihydrotestosterone Experimental and Applied Sciences, Golden, CO, and content (DHT), androstenedione, androstenediol and androstenetriol. of the supplement was verified by HPLC at an independent These steroids may also enhance immunity and protect against laboratory (Integrated Biomolecule, Tuscon, AZ). Subjects infection [16–19]. DHT is the most potent androgen [20] and were asked to maintain normal diet and activity patterns binds to the androgen receptor more tightly than any other throughout the study. Subjects recorded dietary intake and androgen [21]. Some investigators have demonstrated that the activity for the two days prior to each blood draw. Diet analysis beneficial effect of these other steroid hormones, in terms of was performed with Nutritionist 4 software. Six additional immune function, may be greater than DHEA [17–19]. How- young male subjects (ages 21 to 32) were included only as an ever, the immunoenhancing effect of these steroids or combi- age comparison group. These young subjects also completed a nation of steroids has only been observed in animal models, medical history and a dietary evaluation to eliminate any sub- and, to our knowledge, these have not been tested in humans. jects with known chronic disease and/or consuming dietary The metabolic fate of ingested DHEA and androstenedione supplements. The young subjects did not consume oral placebo is not clear. DHEA may be converted to androstenedione or or dietary supplement. Instead, this group was included only to androstenediol, and either of these steroids may undergo further document the age-related changes of immune function. conversion to testosterone, a more potent androgen. Testoster- one can undergo further conversion to DHT by the enzyme Blood Collection and Peripheral Blood 5-alpha reductase or may undergo aromatization resulting in Mononuclear Cell (PBMC) Isolation estrogen formation. In order to maximize the “androgenic” effect of these steroids and reduce the possibility of steroid Fasting blood samples were collected from the older sub- conversion to DHT or estrogens, several herbal extracts have jects between 6:30 and 8:00 am prior to supplementation and been added to nutritional supplements. These