Which vitamin is particularly known for enhancing immune function?

Vitamin A is particularly known for enhancing immune function, primarily due to its role in maintaining the integrity and function of mucosal surfaces, which are the first line of defense against infections. This vitamin is crucial for the development and differentiation of immune cells, such as T cells and B cells, which are essential in the body's immune response.

Additionally, vitamin A is involved in the production of antibodies and plays a significant role in the maintenance of epithelial tissues, contributing to the barriers that prevent pathogens from entering the body. It has also been shown that adequate levels of vitamin A can help reduce the severity and duration of infections.

While other vitamins such as vitamin D, vitamin K, and vitamin E also play roles in immune function, vitamin A is most prominently recognized for its direct impact on the immune system, making it the most relevant choice in this context.