Which mineral is critical for immune function and deficiency increases susceptibility to infection in aging?

• A. Zinc
• B. Iron
• C. Selenium
• D. Copper

Answer: (A)

Zinc is a trace mineral essential for robust immune function, especially as we age. It acts as a cofactor for many enzymes and proteins that drive the development and activity of both innate and adaptive immune cells. It helps maintain the integrity of mucosal barriers, supports neutrophil and macrophage function, and influences the activity of natural killer cells and T and B lymphocytes. Zinc also participates in signaling pathways that regulate cytokine production, which coordinates the immune response.

In older adults, zinc status often declines because of lower intake, diminished absorption, and altered metabolism. This can lead to immunosenescence, with fewer naïve T cells, reduced T cell–mediated responses, and weaker phagocytic and NK cell activity. As a result, susceptibility to infections increases, and responses to vaccines can be blunted. While iron, selenium, and copper also play roles in immunity, zinc’s broad and direct impact on both arms of the immune system makes it the most critical mineral for preventing infection risk in aging.