Effect of zinc supplementation on the immune status of healthy older individuals aged 55-70 years: the ZENITH Study.
Aging is associated with alterations in the immune system, effects which may be exacerbated by inadequate zinc (Zn) status. We examined the relationship between Zn status and markers of immunity and the effect of supplementation with 15 mg or 30 mg Zn/d for 6 months on immune status in healthy individuals. Zn status was assessed by dietary intake and biochemical indices. Immune status was assessed by multiple flow cytometric methods. At baseline, Zn concentration was positively associated with lymphocyte subpopulation counts and T-lymphocyte activation. Zn supplementation of 30 mg/d significantly lowered B-lymphocyte count, albeit at month 3 only. Lower doses of Zn (15 mg Zn/d) significantly increased the ratio of CD4 to CD8 T lymphocytes at month 6. Overall, these findings suggest that total Zn intake (diet plus supplementation) of up to 40 mg Zn/d do not have significant long-term effects on immune status in apparently healthy persons aged 55-70 years.
Hodkinson
Clare F
CF
Northern Ireland Centre for Food and Health (NICHE), University of Ulster, Coleraine, Northern Ireland.
Kelly
Mary
M
Alexander
H Denis
HD
Bradbury
Ian
I
Robson
Paula J
PJ
Bonham
Maxine P
MP
O'Connor
Jacqueline M
JM
Coudray
Charles
C
Strain
J J
JJ
Wallace
Julie M W
JM
D000368:Aged; D001402:B-Lymphocytes / Q000166:cytology; D015415:Biomarkers / Q000032:analysis; D016516:CD4-CD8 Ratio; D003300:Copper / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D007109:Immunity / Q000187:drug effects*; D007501:Iron / Q000097:blood; D008213:Lymphocyte Activation / Q000276:immunology; D018655:Lymphocyte Count; D016131:Lymphocyte Subsets / Q000166:cytology; D008297:Male; D008875:Middle Aged; D010919:Placebos; D013601:T-Lymphocytes / Q000276:immunology; D014131:Trace Elements / Q000097:blood / Q000627:therapeutic use*; D015032:Zinc / Q000097:blood / Q000627:therapeutic use*
D015415:Biomarkers; D010919:Placebos; D014131:Trace Elements; D003300:Copper; D007501:Iron; D015032:Zinc