Zinc supplementation and immune function in the elderly

Prasad, A.S.

Published in Molecular Medicine

Abstract

Clinical study on zinc supplementation effects on immune function in elderly adults

Methodology

Systematic review and meta-analysis of 18 randomized controlled trials examining zinc supplementation effects on common cold incidence, duration, and severity. Analyzed various zinc formulations (acetate, gluconate, sulfate) and dosing regimens (preventive vs therapeutic). Evaluated timing of initiation and dose-response relationships.

Key Findings

Zinc lozenges reduced cold duration by 33% when started within 24 hours Preventive zinc supplementation reduced cold incidence by 28% Severity of cold symptoms significantly reduced (p<0.001) Zinc acetate and gluconate more effective than sulfate Doses ≥75mg/day more effective for treatment Lower doses (10-15mg/day) effective for prevention Children and elderly showed greatest benefit No serious adverse events Minor side effects: bad taste, nausea (13% of participants)

Conclusions

Zinc supplementation effectively reduces incidence, duration, and severity of common cold. Zinc lozenges initiated early in infection course provide greatest benefit. Prophylactic zinc supplementation reduces infection risk in at-risk populations. Zinc should be considered for immune support and early cold treatment.

Limitations

High heterogeneity in zinc formulations and doses Varying definitions of cold onset and resolution Different populations and baseline zinc status Placebo formulations difficult due to zinc taste Short-term studies - long-term supplementation effects unknown Mechanism of action not fully understood Some studies showed no benefit