All of the following are true about folic acid except ?
**Core Concept**
Folic acid, also known as vitamin B9, is a water-soluble vitamin essential for various bodily functions including DNA synthesis, cell division, and the maintenance of healthy red blood cells. It plays a crucial role in preventing anemia and supporting fetal development during pregnancy.
**Why the Correct Answer is Right**
Folic acid is a crucial co-factor for the enzyme dihydrofolate reductase (DHFR), which is necessary for the conversion of folic acid into its active form, tetrahydrofolate (THF). THF is then used in the synthesis of purines and pyrimidines, which are the building blocks of DNA. Folic acid deficiency can lead to a decrease in THF levels, resulting in impaired DNA synthesis and cell division. This can cause megaloblastic anemia, a condition characterized by the production of abnormally large red blood cells.
**Why Each Wrong Option is Incorrect**
**Option A:** This statement is true. Folic acid is indeed essential for the maintenance of healthy red blood cells.
**Option B:** This statement is true. Folic acid plays a crucial role in the prevention of neural tube defects (NTDs) in the developing fetus during pregnancy.
**Option C:** This statement is false. Folic acid is not contraindicated in patients with kidney disease. In fact, folic acid supplementation is often recommended for patients with chronic kidney disease to prevent anemia and other complications.
**Clinical Pearl / High-Yield Fact**
It's essential to note that folic acid supplementation should not be used as a substitute for iron therapy in patients with iron deficiency anemia. Folic acid can actually worsen the condition by promoting the production of red blood cells that are deficient in hemoglobin.
**Correct Answer: C. Folic acid is not contraindicated in patients with kidney disease.