Which vitamin is most associated with immune function?

Vitamin C is highly regarded for its vital role in supporting the immune system. It is a powerful antioxidant that helps protect cells from damage caused by free radicals, thereby enhancing the immune response. This vitamin contributes to the production and function of white blood cells, which are crucial for fighting infections. Additionally, vitamin C is involved in various biochemical processes, including the synthesis of collagen, which is important for maintaining healthy skin and mucous membranes that act as barriers against pathogens.

The other vitamins listed, while important for overall health, do not have the same direct and prominent association with immune function as vitamin C. For instance, vitamin A is essential for maintaining the integrity of skin and mucosal cells but does not have as potent an effect on immune response compared to vitamin C. Vitamin D plays a role in the immune system as well, impacting pathogen-fighting effects, but its relationship is less direct. Similarly, vitamin K is crucial for blood clotting and bone health but does not significantly influence immune functions.