Background: Micronutrient deficiencies are common in the older adults and exacerbate these changes. Micronutrient supplementation has been proposed as a method to reverse immunosenescence. However, its effectiveness has been inconsistent. This systematic review and meta-analysis of randomized controlled trials (RCTs) evaluate the impact of micronutrient supplementation on immune function in older adults.
Methods: A comprehensive literature search was conducted in PubMed, the Cochrane Library, and Google Scholar, yielding 810 records. After removal of duplicates and applying the inclusion criteria, nine RCTs were included. Data extraction was performed according to the PRISMA checklist. Risk of bias was assessed using the Cochrane ROB2 tool, and meta-analysis was conducted using a random-effects model.
Results: Micronutrient supplementation significantly improved immune function, with an overall standardized mean difference (SMD) of 0.14 (95% CI: 0.07 to 0.35, p < 0.01). Subgroup analyzes revealed significant reductions in inflammatory biomarkers. The meta-analysis demonstrated that vitamin D supplementation led to a decrease in inflammation (SMD: -0.40, 95% CI: -0.48 to -0.32, p < 0.01), increased immune cell activity (SMD: 0.40, 95% CI: 0.32 to 0.47, p < 0.01), and enhanced antioxidant status (SMD: 0.46, 95% CI: 0.37 to 0.55, p < 0.01). Analysis by micronutrient type revealed that vitamin E had the largest effects on cellular immunity, while multivitamin supplements showed significant improvements in overall immune function.
Conclusion: Micronutrient supplementation enhances immune function in elderly adults by reducing inflammation, increasing T lymphocyte levels, and improving antioxidant status.
Keywords: immune function; immunosenescence; meta-analysis; micronutrient supplementation; older adults; systematic review.
Copyright © 2026 Li, Wang, Xiao and Li.