Zinc supplementation has no effect on circulating levels of peripheral blood leucocytes and lymphocyte subsets in healthy adult men

• Published in: British journal of nutrition Vol. 89; no. 5; pp. 695 - 703
• Main Authors: Bonham, Maxine, O'Connor, Jacqueline M., Alexander, H. Denis, Coulter, James, Walsh, Paula M., McAnena, Liadhan B., Downes, C. Stephen, Hannigan, Bernadette M., Strain, J. J.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.05.2003
• Subjects: administration & dosage; Adult; adverse effects; analysis; Analysis of Variance; Biological and medical sciences; blood; Ceruloplasmin; Ceruloplasmin - analysis; copper; Copper - administration & dosage; Copper - blood; Diet; Dietary Supplements; Double-Blind Method; drug effects; duration; enzyme activity; experimental diets; Feeding. Feeding behavior; ferroxidase; Flow Cytometry; Fundamental and applied biological sciences. Psychology; human nutrition; Humans; Immune response; Immune status; immunity; immunology; Infectious diseases; Leucocytes; Leukocyte Count; Lymphocyte Subsets; Lymphocyte Subsets - drug effects; Lymphocyte Subsets - immunology; Lymphocytes; Male; men; No-Observed-Adverse-Effect Level; nutritional status; protein content; repletion; seasonal variation; Seasonal variations; Seasons; Side effects; superoxide dismutase; Superoxide Dismutase - blood; T-lymphocytes; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Zinc; Zinc - administration & dosage; Zinc - adverse effects; Zinc - blood; Leucocytes; Immune status; Lymphocyte subsets; Zinc; Human; Immune response; Leukocyte; Metal ion; Supplementation; Subunit; Inorganic element; Lymphocyte; Immune system
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1079/BJN2003826

As a result of evidence documenting harmful effects of Zn supplementation on immune function and Cu status, thirty-eight men were recruited onto a Zn supplementation trial. The aim was to examine the effects of chronic Zn supplementation on circulating levels of peripheral blood leucocytes and lymphocyte subsets. Subjects (n 19) took 30 mg Zn/d for 14 weeks followed by 3 mg Cu/d for 8 weeks to counteract adverse effects, if any, of Zn supplementation on immune status resulting from lowered Cu status. A control group (n 19) took placebo supplements for the duration of the trial. Dietary intakes of Zn approximated 10 mg/d. Blood samples, taken throughout the trial, were assessed for full blood profiles and flow cytometric analyses of lymphocyte subsets. Putative indices of Cu status were also examined. Results indicate that there was no effect of Zn supplementation on circulating levels of peripheral blood leucocytes or on lymphocyte subsets. Cu status was also unaltered. Independent of supplement, there appeared to be seasonal variations in selected lymphocyte subsets in both placebo and supplemented groups. Alterations in circulating levels of B cells (cluster of differentiation (CD) 19), memory T cells (CD45RO) and expression of the intracellular adhesion molecule-1 (CD54) on T cells were observed. Findings indicated no adverse effects of Zn supplementation on immune status or Cu status and support the US upper level of Zn tolerance of 40 mg/d. The seasonal variations observed in lymphocyte subsets in the group as a whole could have implications for seasonal variability in the incidence of infectious diseases.