Failure of dietary zinc supplementation to improve the antibody response to influenza vaccine

The effect of administering zinc gluconate on the immune response of elderly subjects to influenza vaccine was studied. Sixty health men and women aged 64 to 90 years (mean=74) were randomly assigned to two groups and asked to discontinue all mineral and vitamin supplements for a period of one month. Members of each group were then started on either 50 mg of elemental zinc as zinc gluconate or an identical appearing and tasting placebo in a double blinded manner for one month. Blood samples were then obtained to determine serum zinc and copper levels, and antibody titers to A/Philippines, A/Chile, B/USSR, B/Ann Arbor strains of influenza virus. All individuals were then immunized using trivalent influenza vaccine (Fluogen, Park-Davis), and continued on either zinc or placebo for one month. A second blood sample was then obtained and similarly analyzed. Serum zinc levels increased in both groups, however in the group receiving zinc gluconate supplementation there was a 5.8-fold greater increase than in the control group (p