title: Zinc status and age-related changes in peripheral blood leukocyte subpopulations in healthy men and women aged 55-70 y: the ZENITH study.
abstract: OBJECTIVE
  To determine zinc status and age-related changes in the immune function of healthy late-middle-aged men and women (aged 55-70 y).
  
  
  METHODS
  Observational study.
  
  
  METHODS
  Population of Northern Ireland.
  
  
  METHODS
  Apparently healthy, free-living individuals (45 men, 48 women) aged 55-70 y.
  
  
  METHODS
  Zinc status markers were analysed by flame atomic absorption spectrometry and commercially available kits. Immune function was assessed by flow cytometry.
  
  
  RESULTS
  Serum and erythrocyte zinc concentrations were 13.0 (s.d. 1.40) micromol/l and 222 (s.d. 48.2) micromol/l, respectively. Serum alkaline phosphatase (ALP) concentrations were 76.8 (s.d. 16.1) U/l; women showed significantly higher concentrations of ALP (P = 0.011). Women demonstrated (1) a significant inverse correlation in naive T lymphocytes, specifically naive T-helper lymphocytes (% expression, r = -0.364, P = 0.007 and absolute count, r = -0.275, P = 0.036) with age and (2) a significant positive correlation between late activation of T lymphocytes (% expression, r = 0.299, P = 0.019 and absolute count, r = 0.260, P = 0.039) with advancing age. Men demonstrated a significant positive correlation in the % expression of (CD3-/CD16+/CD56+) natural killer (NK) cells with age (r = 0.316, P = 0.017).
  
  
  CONCLUSIONS
  Between the ages of 55 and 70 y, healthy individuals experience significant alterations in immune function; however, such changes appear largely sex specific. Given the reported importance of adequate zinc status in maintaining optimal immune function, further studies are required to explore the effect of enhanced zinc status on emerging immune deficiencies in cell-mediated immunity in healthy 55-70 y olds.
authors.affiliation: Northern Ireland Centre for Food and Health (NICHE), University of Ulster, Coleraine, Northern Ireland, UK.
authors.forename: C F
authors.initials: CF
authors.lastname: Hodkinson
authors.forename: M
authors.initials: M
authors.lastname: Kelly
authors.forename: C
authors.initials: C
authors.lastname: Coudray
authors.forename: W S
authors.initials: WS
authors.lastname: Gilmore
authors.forename: B M
authors.initials: BM
authors.lastname: Hannigan
authors.forename: J M
authors.initials: JM
authors.lastname: O'Connor
authors.forename: J J
authors.initials: JJ
authors.lastname: Strain
authors.forename: J M W
authors.initials: JM
authors.lastname: Wallace
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology / Q000502:physiology; D007962:Leukocytes / Q000276:immunology* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009660:Northern Ireland; D009749:Nutrition Surveys; D009752:Nutritional Status / Q000502:physiology*; D012016:Reference Values; D012737:Sex Factors; D013054:Spectrophotometry, Atomic / Q000379:methods; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology; D015032:Zinc / Q000097:blood*
chemical_list: D015415:Biomarkers; D000469:Alkaline Phosphatase; D015032:Zinc