About 35% of older adults in the United States, Canada, and Europe are deficient in one or more micronutrients. Older adults are at increased risk for vitamin and mineral deficiencies, which contribute to age-related immune system decline.

Multiple nutrients support immune function. Vitamin C is important for neutrophil phagocytosis, motility, reactive oxygen species (ROS) generation, antimicrobial activity, and monocyte locomotion. Zinc deficiency alters the numbers and functions of neutrophils, monocytes, natural killer T cells, and B cells and is an important mineral for neutrophil and monocyte chemotaxis. Vitamin D is critical for both innate and adaptive immune function and is required for the induction of the cathelicidin antimicrobial peptide gene in activated monocytes and macrophages.

Some evidence suggests that taking a multivitamin and mineral supplement (MVM) could improve immune function in people 55 years of age and older. To test this hypothesis, researchers conducted a double-blind, randomized, placebo-controlled trial in healthy adults aged 55–75, providing them with a MVM formulated to improve immune function or an identical inactive placebo control to be taken daily for 12 weeks. Before and after treatment, the researchers measured: (1) vitamin C, zinc, and vitamin D status in their blood; (2) immune function (i.e., whole blood bacterial killing activity, neutrophil phagocytic activity, and reactive oxygen species production); (3) immune status (salivary IgA and plasma cytokine/chemokine levels); and (4) self-reported health status.

The results of the experiment revealed that zinc and vitamin C levels were significantly higher in study participants after 12 weeks of MVM supplementation. We did not observe statistically significant changes in immune outcomes, but we observed a statistically significant decrease in reported disease length and severity in the MVM group compared to the placebo group (as shown in the table below). This suggests that MVM supplementation may improve immune outcomes in older adults.

Fantacone, M. L., Lowry, M. B., Uesugi, S. L., Michels, A. J., Choi, J., Leonard, S. W., Gombart, S. K., Gombart, J. S., Bobe, G., & Gombart, A. F. (2020). The Effect of a Multivitamin and Mineral Supplement on Immune Function in Healthy Older Adults: A Double-Blind, Randomized, Controlled Trial. Nutrients, 12(8), 2447. [Link]