What deficiency can cause macrocytic anemia?

Macrocytic anemia is characterized by the production of abnormally large red blood cells, which can occur due to a deficiency in certain vitamins, namely vitamin B12 and folate. The correct answer focuses on folate deficiency, which is crucial for the synthesis of DNA during red blood cell formation. Without adequate folate, the process of red blood cell production is hindered, leading to the production of larger, immature cells—contributing to macrocytic anemia.

Vitamin B12 is also vital in preventing macrocytic anemia, as it works alongside folate in DNA synthesis. However, because the question specifies only one option as the cause of macrocytic anemia, the emphasis on folate deficiency highlights its direct connection to the condition.

While vitamin C and vitamin K deficiencies have their own implications in terms of overall health and blood coagulation, they are not linked to the development of macrocytic anemia. Vitamin C primarily aids in iron absorption and collagen formation, while vitamin K is crucial for blood clotting. Thus, their deficiency does not result in the specialized red blood cell changes seen in macrocytic anemia, which focuses specifically on folate and vitamin B12.