Which vitamin is important for vision and immune function?

Vitamin A is essential for both vision and immune function. It plays a crucial role in the formation of rhodopsin, a pigment in the retina that is necessary for vision in low light conditions. Without adequate Vitamin A, one may experience difficulties in seeing at night, a condition known as night blindness.

Moreover, Vitamin A is vital for the immune system. It helps maintain the integrity of skin and mucosal cells, which act as barriers against pathogens. Additionally, this vitamin supports the functioning of various immune cells, enhancing the body's ability to fight off infections.

In contrast, the other vitamins listed serve different primary functions. Vitamin K is mainly known for its role in blood clotting, Vitamin E acts as an antioxidant protecting cells from damage, and Vitamin D is best recognized for its importance in bone health and calcium absorption. Each vitamin has its specific roles, but Vitamin A stands out in the context of vision and immune function.