Folate deficiency
Symptoms, at-risk groups, and clinical context for folate deficiency. Sourced from NIH Office of Dietary Supplements and StatPearls.
Folate deficiency is uncommon in the US since mandatory grain fortification began in 1998, but it persists in pregnant women, people with malabsorption, and those on certain medications. Inadequate folate during early pregnancy is the leading cause of neural tube defects (spina bifida, anencephaly).
Common symptoms
- Fatigue, weakness, shortness of breath (from megaloblastic anemia)
- Sore tongue (glossitis) — smooth, red, painful 'beefy' tongue
- Mouth ulcers
- Headache, heart palpitations
- Difficulty concentrating, irritability
- Diarrhea or other GI symptoms
- Changes in hair, skin, or fingernail pigmentation
- Forgetfulness or mood changes (especially older adults)
- Most folate deficiency is asymptomatic until anemia develops
At-risk groups
- Women planning pregnancy or in early pregnancy (CRITICAL — neural tube defect prevention)
- Women of reproductive age generally (defects occur before pregnancy is recognized)
- People with alcohol use disorder
- People with GI conditions affecting absorption (celiac, tropical sprue, Crohn's)
- People taking methotrexate, sulfasalazine, or some anticonvulsants (phenytoin, carbamazepine)
- People with MTHFR gene variants (may need methylfolate form)
- Older adults, especially institutionalized
- People on hemodialysis
When to see a doctor: All women who could become pregnant should take 400 mcg folic acid daily — this is one of the most important nutritional recommendations and prevents up to 70% of neural tube defects. Otherwise, persistent fatigue with sore tongue or mouth ulcers warrants a serum or RBC folate test plus B12 (deficiencies share symptoms but have different consequences).
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Related deficiencies
Nutrients with overlapping symptoms — useful when investigating an unclear clinical picture.