1.
Herbal supplements and athlete immune function--what's proven, disproven, and unproven?
Senchina, DS, Shah, NB, Doty, DM, Sanderson, CR, Hallam, JE
Exercise immunology review. 2009;:66-106
Abstract
The purpose of this paper is to critically evaluate current immunological and clinical literature regarding the effects of herbal preparations on athlete immune function. First, we review rates of herbal supplement use by athletes. Second, we use ginseng (Panax ginseng) and coneflower (Echinacea spp.) as models for examining how herbal supplements may influence immune function within the contexts of exercise and sport, while briefly considering several other popular herbal products. Third, we proffer several evidence-based hypotheses to explain apparent discrepancies among the cumulative data, concomitantly advancing a novel conceptual framework which may be useful to understanding herbal supplements and athlete immune function using Echinacea supplements as a model. Fourth, we apply the proposed framework to some prospective data regarding the effects of Echinacea pallida and Echinacea simulata on in vitro cytokine production and cell proliferation in peripheral blood mononuclear cells collected from male collegiate wrestlers and soccer players during training. Fifth and finally, we evaluate the current knowledge on herbal supplements and athlete immune function, identify gaps and limitations in knowledge, and advance several possible options for future research.
2.
Immune functions are maintained in healthy men with low zinc intake.
Pinna, K, Kelley, DS, Taylor, PC, King, JC
The Journal of nutrition. 2002;(7):2033-6
Abstract
Although immunity is impaired during severe zinc deficiency, there is limited information about the effects of mild zinc depletion on immune response in humans. We evaluated the effects of a zinc-restricted diet (4.6 mg/d) on several indices of immunity in 8 healthy men. The subjects consumed zinc supplements with 9.1 mg/d during the 5-wk baseline (BL) and 5-wk repletion (RP) periods, and placebos during the 10-wk zinc-restriction (ZR) period. Leukocyte numbers and functions were studied at the end of each metabolic period. After ZR, there were reductions in the proliferation of peripheral blood mononuclear cells (PBMNC) stimulated with phytohemagglutinin (PHA, 1.2, 2.5, 5.0, 10.0 [corrected] and 20.0 mg/L; P < 0.01) and in the in vitro secretion of interleukin-2 receptor (IL-2R) (PHA, 2.5 mg/L; P = 0.058). These variables remained reduced (P < 0.05) even after 5 wk of zinc repletion. The amount of zinc consumed did not alter the numbers of circulating neutrophils, monocytes and lymphocytes, the in vitro PBMNC secretion of interferon-gamma and tumor necrosis factor-alpha or neutrophil superoxide production. The results suggest that changes in lymphocyte proliferation and IL-2R expression may be early markers of mild zinc deficiency.