Folate deficiency

Last updated: July 5, 2023

Summarytoggle arrow icon

Folate (vitamin B9) is an essential coenzyme that enables critical biochemical reactions. Dietary sources include naturally folate-rich foods such as leafy green vegetables, fruit and liver, but also supplements and fortified foods. Malnutrition and excessive alcohol use are the most common causes of deficiency. Folate deficiency causes impaired DNA synthesis, which leads to megaloblastic anemia. The clinical picture of anemia is similar to that of vitamin B12 deficiency, although folate deficiency is generally not associated with neurological manifestations. Diagnosis is based on laboratory findings such as macrocytosis, hyperhomocysteinemia, and normal levels of methylmalonic acid. Therapy consists of oral supplementation.

Physiologytoggle arrow icon

Etiologytoggle arrow icon

Folate deficiency is the most common vitamin deficiency in the US.

Pathophysiologytoggle arrow icon

Decreased folate levels leads to decreased levels of tetrahydrofolate. This, in term, leads to the following effects:

Clinical featurestoggle arrow icon

Unlike vitamin B12 deficiency, folate deficiency does not result in neurological symptoms.

Diagnosticstoggle arrow icon

If folate deficiency is suspected, always exclude the possibility of vitamin B12 deficiency.

Treatmenttoggle arrow icon

  • Oral folate supplementation for four months or until hematologic recovery takes place
  • Nutritional counseling to increase folate intake

Because of the risk of neural tube defects, it is recommended that women planning to become pregnant initiate folate supplementation before conception.

Referencestoggle arrow icon

  1. Stanger O. Physiology of folic acid in health and disease. Curr Drug Metab. 2002; 3 (2): p.211-23.
  2. Bebel Stargrove M, Treasure J, McKee DL. Herb, Nutrient, and Drug Interactions, Clinical Implications and Therapeutic Strategies. Elsevier ; 2008
  3. Folate and Cancer Risk - Position Statement. . Accessed: April 27, 2018.
  4. Vollset SE, Clarke R, Lewington S, et al. Effects of folic acid supplementation on overall and site-specific cancer incidence during the randomised trials: meta-analyses of data on 50 000 individuals. The Lancet. 2013; 381 (9871): p.1029-1036.doi: 10.1016/s0140-6736(12)62001-7 . | Open in Read by QxMD
  5. Devalia V, Hamilton MS, Molloy AM. Guidelines for the diagnosis and treatment of cobalamin and folate disorders. Br J Haematol. 2014; 166 (4): p.496-513.doi: 10.1111/bjh.12959 . | Open in Read by QxMD

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 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer