Nutritional and macrocytic anemias can be caused by a deficiency of folate. This deficiency can result from diets devoid of raw fruits, vegetables or other foods rich in folic acid, as may be the case with chronic alcoholics, drug addicts, the elderly or persons of low socioeconomic status, etc. In addition, low serum folate during pregnancy has been associated with neural tube defects in the fetus. Dietary deficiency and malabsorption are the major causes of folate deficiency in humans. Folate is necessary for normal metabolism, DNA synthesis and red blood cell regeneration. Untreated deficiencies may lead to megaloblastic anemia.
Since a deficiency of either vitamin B12 or folate can cause megaloblastic anemia, it is advisable to determine the concentration of both vitamin B12 and folate in order to properly diagnose the etiology of anemia.