title: The effect of zinc and vitamin A supplementation on immune response in an older population.
abstract: OBJECTIVE
  To determine if either supplemental vitamin A, zinc, or both increases cell-mediated immune response in an older population.
  
  
  METHODS
  A double-blind, randomized, controlled trial of supplementation with vitamin A and zinc.
  
  
  METHODS
  Casa Di Riposo Roma III, a public home for older people in Rome, Italy.
  
  
  METHODS
  The health and nutritional status of 178 residents were evaluated. One hundred thirty-six residents agreed to participate in the trial and were randomized into four treatment groups, and 118 of these residents completed the trial.
  
  
  METHODS
  The four treatments consisted of: (1) Vitamin A (800 micrograms retinol palmitate); (2) Zinc (25 mg as zinc sulfate); (3) Vitamin A and Zinc (800 micrograms retinol palmitate and 25 mg as zinc sulfate); (4) Placebo capsules containing starch.
  
  
  METHODS
  Immune tests-counts of leucocytes, lymphocytes, T-cell subsets, and lymphocyte proliferative response to mitogens-were measured before and after supplementation.
  
  
  RESULTS
  Zinc increased the number of CD4 + DR + T-cells (P = .016) and cytotoxic T-lymphocytes (P = .005). Subjects treated with vitamin A experienced a reduction in the number of CD3 + T-cells (P = .012) and CD4 + T-cells (P = .012).
  
  
  CONCLUSIONS
  These data indicate that zinc supplementation improved cell-mediated immune response, whereas vitamin A had a deleterious effect in this older population. Further research is needed to clarify the clinical significance of these findings.
authors.affiliation: National Institute of Health, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Fortes
authors.forename: F
authors.initials: F
authors.lastname: Forastiere
authors.forename: N
authors.initials: N
authors.lastname: Agabiti
authors.forename: V
authors.initials: V
authors.lastname: Fano
authors.forename: R
authors.initials: R
authors.lastname: Pacifici
authors.forename: F
authors.initials: F
authors.lastname: Virgili
authors.forename: G
authors.initials: G
authors.lastname: Piras
authors.forename: L
authors.initials: L
authors.lastname: Guidi
authors.forename: C
authors.initials: C
authors.lastname: Bartoloni
authors.forename: A
authors.initials: A
authors.lastname: Tricerri
authors.forename: P
authors.initials: P
authors.lastname: Zuccaro
authors.forename: S
authors.initials: S
authors.lastname: Ebrahim
authors.forename: C A
authors.initials: CA
authors.lastname: Perucci
mesh_terms: D000368:Aged; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects*; D007958:Leukocyte Count / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects; D008297:Male; D016176:T-Lymphocyte Subsets / Q000187:drug effects; D014801:Vitamin A / Q000008:administration & dosage / Q000276:immunology*; D015032:Zinc / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D014801:Vitamin A; D015032:Zinc