folatstatus

Folatstatus, or folate status, refers to the level of folate (vitamin B9) in the body's tissues and circulation, indicating whether folate requirements are met for DNA synthesis and cell division. Folate exists in dietary polyglutamates and in circulating mono- and polyglutamated forms. Assessment is typically performed by measuring serum (plasma) folate and red blood cell (RBC) folate concentrations. Serum folate reflects recent intake, while RBC folate indicates longer-term stores over several months; RBC folate is often considered the more stable marker of status. Total homocysteine can be elevated when folate (or vitamin B12) is deficient, serving as a functional marker.

Reference ranges vary by laboratory and method. RBC folate is usually reported in ng/mL or nmol/L, with lab-specific cutoffs. Folate deficiency can cause megaloblastic anemia and, in early pregnancy, increases the risk of neural tube defects in the fetus. Low folate intake is also associated with elevated homocysteine, linked to cardiovascular risk and adverse pregnancy outcomes. High folate intake is generally safe but can mask vitamin B12 deficiency when taken in excess.

Causes of low folate status include inadequate dietary intake, poor absorption (for example, celiac disease or inflammatory bowel disease), alcoholism, certain medications (such as methotrexate and some anticonvulsants), pregnancy, and rapid growth. Management typically involves dietary improvement and, when indicated, folic acid or 5-methyltetrahydrofolate (5-MTHF) supplementation, guided by clinical context. Public health measures such as folic acid fortification of foods have reduced deficiency rates in many populations.

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