All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Causes of folic acid deficiency
Medical expert of the article
Last reviewed: 06.07.2025
Since folate reserves in the body are limited and the daily requirement is high, folate deficiency and megaloblastic anemia may develop 1-6 months after folic acid intake is stopped. The following sequence of events is typical for folate deficiency: during the first 3 weeks, a decrease in the concentration of folic acid in the blood serum is noted, after about 11 weeks, hypersegmentation of the nuclei of neutrophils, basophils, and eosinophils (an indicator of folate deficiency and a reliable predictor of megaloblastic hematopoiesis) is detected during the examination of a blood smear, a little later a decrease in the concentration of the vitamin in erythrocytes is detected (17 weeks), macro-ovalocytosis of erythrocytes (18 weeks), megaloblastic hematopoiesis in the red bone marrow (19 weeks), and the full-blown clinical picture of megaloblastic anemia develops after 19-20 weeks.
The concentration of folate in red blood cells is a more accurate indicator of its reserves in the body than the content in serum, since it does not depend on the intake of the vitamin with food in the last days. However, megaloblastic anemia can develop even with a normal content of folate in red blood cells and blood serum (for example, only 50% of pregnant women with megaloblastic anemia have a reduced concentration of folates in red blood cells).
Folic acid deficiency is one of the most common forms of vitamin deficiency, occurring due to insufficient intake of folate into the body, malabsorption syndrome, alcoholism, hyperthyroidism in children, scurvy, deficiency of vitamins B 12 and C, liver disease, Crohn's disease, ulcerative colitis, malignant neoplasms, myeloproliferative diseases, sepsis, hemolytic and sideroblastic anemia, acute inflammatory diseases (especially of the skin), pregnancy.
Taking large doses of vitamin C (more than 2 g) increases the excretion of folic acid from the body (it is necessary to increase the daily intake of folic acid).
[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ], [ 7 ], [ 8 ], [ 9 ]