Folic Acid Deficiency

Folic acid present in most fruits and vegetables (especially citrus fruits and green leafy vegetables)

Daily requirements of 50–100 mcg/day usually met in the diet

Total body stores of folate enough to supply requirements for 2–3 mo

Most common cause of folate deficiency is inadequate dietary intake, which occurs in

• Alcoholics

• Anorectic patients

• Persons who do not eat fresh fruits and vegetables

• Those who overcook food

Other causes

• Decreased absorption (tropical sprue; drugs, eg, phenytoin, sulfasalazine, trimethoprim-sulfamethoxazole)

• Increased requirement (chronic hemolytic anemia, pregnancy, exfoliative skin disease)

• Loss (dialysis)

• Inhibition of reduction to active form (methotrexate)

Megaloblastic anemia, which may be severe

Glossitis and vague GI disturbances (eg, anorexia, diarrhea)

No neurologic abnormalities, unlike vitamin B₁₂ deficiency

Megaloblastic anemia identical to that in vitamin B₁₂ deficiency (eg, macro-ovalocytes, hypersegmented neutrophils (see Vitamin B12 Deficiency)

Red blood cell folate level < 150 ng/mL

Serum vitamin B₁₂ level normal

Distinguish from vitamin B₁₂ deficiency as well as from pure anemia of liver disease (macrocytic anemia with target cells but no megaloblastic changes)

Folic acid, 1 mg orally once daily, for patients with folic acid deficiency or increased folic acid requirements

Rapid improvement in sense of well-being, reticulocytosis in 5–7 days, and total correction of hematologic abnormalities within 2 months