Megaloblastic anemia due to folic acid deficiency is commonly due to –
**Core Concept**
Megaloblastic anemia is a type of anemia characterized by the production of abnormally large red blood cells that are unable to function properly. Folic acid deficiency is a common cause of megaloblastic anemia, leading to impaired DNA synthesis and cell division.
**Why the Correct Answer is Right**
Folic acid is essential for the synthesis of purines and pyrimidines, which are the building blocks of DNA. A deficiency in folic acid leads to reduced DNA synthesis, resulting in the production of large and immature red blood cells. This is because the cells are unable to divide properly due to a lack of necessary nucleotides. The bone marrow attempts to compensate for the defect by producing more red blood cells, leading to an accumulation of these abnormal cells.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because malabsorption of folic acid is a common cause of deficiency, but it is not the most common cause. Malabsorption can lead to a deficiency, but it is not the primary reason for folic acid deficiency in most cases.
* **Option B:** This option is incorrect because iron deficiency is a different type of anemia altogether, characterized by a decrease in the number of red blood cells or the amount of hemoglobin in the blood.
**Clinical Pearl / High-Yield Fact**
It's essential to note that megaloblastic anemia can be caused by other factors besides folic acid deficiency, including vitamin B12 deficiency. A thorough evaluation of the patient's diet, laboratory results, and medical history is necessary to determine the underlying cause of the anemia.
**Correct Answer:** C.