Which micronutrient plays a role in immune function?

Vitamin C is essential for immune function due to its role as an antioxidant and its involvement in various cellular functions necessary for both the innate and adaptive immune system. It acts to protect cells from oxidative stress, which can hinder immune function. Additionally, vitamin C is crucial in the production of collagen, which helps maintain the integrity of skin and mucosal barriers, essential for preventing pathogens from entering the body.

Furthermore, vitamin C aids in the proliferation and function of immune cells, particularly lymphocytes and phagocytes, enhancing their ability to respond to infections. It is also known to improve the skin's defense system and assists in the absorption of iron, which is critical for carrying oxygen in the blood and supporting overall energy levels and immune responses.

The other options do not have the same direct impact on immune function as vitamin C. While protein is vital for antibody production and cell repair, it does not specifically target immune response enhancement. Calcium plays a role in many physiological processes, including bone health and muscle function, but it does not directly influence immunity. Carbohydrates are primarily a source of energy for the body and do not have a direct role in modulating immune responses.