Which vitamin deficiency is most commonly associated with anemia?

Vitamin B12 deficiency is most commonly associated with anemia because it plays a crucial role in the production of red blood cells. This vitamin is vital for DNA synthesis, and without adequate B12, the body cannot produce enough healthy red blood cells, leading to a specific type of anemia known as pernicious anemia. This condition is characterized by larger-than-normal red blood cells that are ineffective at carrying oxygen.

In contrast, while the other vitamins listed have important roles in the body, they are not primarily linked to the development of anemia. Vitamin D is essential for calcium absorption and bone health, Vitamin A is critical for vision and immune function, and Vitamin K is necessary for blood clotting. Therefore, their deficiencies do not directly lead to the red blood cell production issues seen in B12 deficiency anemia.