Folate deficiency
- Overview
- Theory
- Diagnosis
- Management
- Follow up
- Resources
Treatment algorithm
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
at risk of folate deficiency due to pregnancy or lactation
oral folic acid + multivitamin supplementation
There is conclusive evidence that use of folic acid supplementation pre-conceptually and during pregnancy reduces the incidence of fetal neural tube defects (NTDs).[19]MRC Vitamin Study Research Group. Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. Lancet. 1991 Jul 20;338(8760):131-7. http://www.ncbi.nlm.nih.gov/pubmed/1677062?tool=bestpractice.com [20]Ramakrishnan U, Grant F, Goldenberg T, et al. Effect of women's nutrition before and during early pregnancy on maternal and infant outcomes: a systematic review. Paediatr Perinat Epidemiol. 2012 Jul;26(suppl 1):285-301. http://www.ncbi.nlm.nih.gov/pubmed/22742616?tool=bestpractice.com [21]Czeizel AE, Dudás I. Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation. N Engl J Med. 1992 Dec 24;327(26):1832-5. https://www.nejm.org/doi/full/10.1056/NEJM199212243272602 http://www.ncbi.nlm.nih.gov/pubmed/1307234?tool=bestpractice.com
The US Preventive Services Task Force advises that the critical period for beginning supplementation is at least 1 month before conception.[35]US Preventive Services Task Force, Barry MJ, Nicholson WK, et al. Folic acid supplementation to prevent neural tube defects: US Preventive Services Task Force reaffirmation recommendation statement. JAMA. 2023 Aug 1;330(5):454-9. https://jamanetwork.com/journals/jama/fullarticle/2807739 http://www.ncbi.nlm.nih.gov/pubmed/37526713?tool=bestpractice.com Persons planning pregnancy, or who could become pregnant, should begin daily folic acid supplementation at least 1 month prior to anticipated conception and continue through the first 2-3 months of pregnancy.[35]US Preventive Services Task Force, Barry MJ, Nicholson WK, et al. Folic acid supplementation to prevent neural tube defects: US Preventive Services Task Force reaffirmation recommendation statement. JAMA. 2023 Aug 1;330(5):454-9. https://jamanetwork.com/journals/jama/fullarticle/2807739 http://www.ncbi.nlm.nih.gov/pubmed/37526713?tool=bestpractice.com
US recommendations vary from 400 to 800 micrograms/day depending upon factors such as diet, inclusion of food fortified with folic acid, socio-economic status, and individual medical history. NIH: dietary supplement fact sheet - folate Opens in new window
Higher folic acid doses (up to 5 mg/day) may be recommended for certain at-risk groups pre-conceptually and during the first 12 weeks of pregnancy.[34]Wilson RD, O'Connor DL. Guideline no. 427: folic acid and multivitamin supplementation for prevention of folic acid-sensitive congenital anomalies. J Obstet Gynaecol Can. 2022 Jun;44(6):707-19. http://www.ncbi.nlm.nih.gov/pubmed/35691683?tool=bestpractice.com [39]National Institute for Health and Care Excellence. Maternal and child nutrition: nutrition and weight management in pregnancy, and nutrition in children up to 5 years. Jan 2025 [internet publication]. https://www.nice.org.uk/guidance/ng247/chapter/Recommendations
Features associated with increased risk for folate deficiency and/or having a fetus with an NTD include: personal or family history of fetal NTD or congenital malformation in the patient or her male partner; previous fetal NTD or congenital malformation birth by the patient; personal history of type 1 or type 2 diabetes or a haematological condition requiring folic acid supplementation; personal use of drugs affecting folic acid absorption or metabolism, or any teratogenic drug.
The National Institutes of Health recommends a dietary folate equivalent of 500 micrograms/day for breastfeeding women. NIH: dietary supplement fact sheet - folate Opens in new window
Primary options
folic acid: low risk: 0.4 mg orally once daily starting at least 1 month prior to pregnancy and continue through 12 weeks’ gestation; high risk: 4 mg orally once daily starting at least 1-3 months before pregnancy and continue through 12 weeks’ gestation
More folic acidHigher doses (up to 5 mg/day) may be recommended in some countries. Consult your local drug information source for more information.
at risk of folate deficiency due to malabsorption disorders, chronic haemolytic disorder, or chronic dialysis
oral folic acid supplementation + treatment of underlying disorder
Correction of underlying cause and/or folic acid supplementation can prevent folate deficiency in patients with malabsorption disorders, such as tropical sprue and coeliac disease.
Increased folate loss occurs in patients with exfoliative dermatitis, chronic haemolytic anaemias, and in those undergoing chronic peritoneal dialysis (due to loss of folate in dialysis fluid).[14]Sevitt LH, Hoffbrand AV. Serum folate and vitamin B12 levels in acute and chronic renal disease. Effect of peritoneal dialysis. Br Med J. 1969 Apr 5;2(5648):18-21. https://pmc.ncbi.nlm.nih.gov/articles/PMC1983016 http://www.ncbi.nlm.nih.gov/pubmed/5776209?tool=bestpractice.com [15]Tu YR, Tu KH, Lee CC, et al. Supplementation with folic acid and cardiovascular outcomes in end-stage kidney disease: a multi-institution cohort study. Nutrients. 2022 Oct 7;14(19):4162. https://www.mdpi.com/2072-6643/14/19/4162 http://www.ncbi.nlm.nih.gov/pubmed/36235814?tool=bestpractice.com Daily folic acid supplementation may be required in these patients to prevent folate deficiency.
Primary options
folic acid: 3-5 mg orally once daily, maximum 15 mg/day
at risk of folate deficiency due to certain drugs
folinic acid
Certain drugs (e.g., sulfasalazine, trimethoprim, methotrexate, pyrimethamine, and anticonvulsants [phenytoin, phenobarbital]) interfere with folate function or absorption by inhibiting enzymes involved in folate metabolism, and by other unknown mechanisms.[32]Wani NA, Hamid A, Kaur J. Folate status in various pathophysiological conditions. IUBMB Life. 2008 Dec;60(12):834-42. http://www.ncbi.nlm.nih.gov/pubmed/18942083?tool=bestpractice.com
Folinic acid can be used to prevent folate deficiency in patients taking drugs that affect dihydrofolate reductase activity, such as methotrexate, pyrimethamine, and trimethoprim.[52]Scaglione F, Panzavolta G. Folate, folic acid and 5-methyltetrahydrofolate are not the same thing. Xenobiotica. 2014 May;44(5):480-8. http://www.ncbi.nlm.nih.gov/pubmed/24494987?tool=bestpractice.com
Folinic acid supplementation can reduce the risk of hepatotoxicity and gastrointestinal adverse effects in patients with rheumatoid arthritis.[58]Liu L, Liu S, Wang C, et al. Folate supplementation for methotrexate therapy in patients with rheumatoid arthritis: a systematic review. J Clin Rheumatol. 2019 Aug;25(5):197-202. http://www.ncbi.nlm.nih.gov/pubmed/29975207?tool=bestpractice.com
In some cases, where a drug has reduced efficacy when administered with folinic acid, a change to another drug may be required.
Primary options
folinic acid: consult specialist for guidance on dose
acquired: macrocytosis without anaemia
oral folic acid replacement
Ruling out vitamin B12 (cobalamin) deficiency is important. Initiation of folic acid therapy may resolve the haematological manifestations of vitamin B12 deficiency, but allow the neurological manifestations of underlying vitamin B12 deficiency to progress.
Oral folic acid therapy should be given to asymptomatic patients with documented folate deficiency, with or without macrocytosis.
Folic acid is better absorbed than natural folate (in food) in malabsorption states; hence, oral therapy is usually adequate.
Haematological findings are corrected after about 8 weeks.[53]Stover PJ, Durga J, Field MS. Folate nutrition and blood-brain barrier dysfunction. Curr Opin Biotechnol. 2017 Apr;44:146-52. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5385290 http://www.ncbi.nlm.nih.gov/pubmed/28189938?tool=bestpractice.com
Primary options
folic acid: children: 1 mg orally once daily; adults: 1-5 mg orally once daily
treatment of underlying disorder
Treatment recommended for ALL patients in selected patient group
Evaluation and treatment of underlying disorders is essential to prevent and treat ongoing deficiency states.
Ongoing losses of folate may need continued replacement (e.g., chronic haemolytic anaemia and exfoliative dermatitis need daily folic acid supplementation).
Patients taking continued folic acid supplementation should have vitamin B12 levels monitored periodically to prevent a missed diagnosis of vitamin B12 deficiency.
Malabsorptive states need correction of underlying disease and vitamin supplementation.
Folate deficiency due to certain drugs may need modification of drug therapy.
Older people and those with poor nutrition (and, therefore, with inadequate intake of folate) should be advised to increase the proportion of folate-rich foods in their diet (i.e., legumes, leafy vegetables, and some fruits).[54]Cordero JF, Do A, Berry RJ. Review of interventions for the prevention and control of folate and vitamin B12 deficiencies. Food Nutr Bull. 2008 Jun;29(2 suppl):S188-95. http://www.ncbi.nlm.nih.gov/pubmed/18709892?tool=bestpractice.com In addition, folic acid may be supplemented by taking multivitamin preparations.
acquired: macrocytic anaemia
oral folic acid replacement
Ruling out vitamin B12 (cobalamin) deficiency is important. Initiation of folic acid therapy may resolve the haematological manifestations of vitamin B12 deficiency, but allow the neurological manifestations of underlying vitamin B12 deficiency to progress.
In severe megaloblastic anaemia where it is essential to initiate therapy immediately, concomitant folic acid and vitamin B12 should be given (until vitamin B12 testing is undertaken). Vitamin B12 and folate status determine subsequent therapy.
Primary options
folic acid: children: 1 mg orally once daily; adults: 1-5 mg orally once daily
OR
folic acid: children: 1 mg orally once daily; adults: 1-5 mg orally once daily
and
cyanocobalamin: consult specialist for guidance on dose
treatment of underlying disorder
Treatment recommended for ALL patients in selected patient group
Assessment and treatment of underlying disorders is essential to prevent and treat ongoing deficiency states.
Ongoing losses of folate may need continued replacement (e.g., chronic haemolytic anaemia and exfoliative dermatitis need continued daily folic acid supplementation).
Patients taking continued folic acid supplementation should have vitamin B12 levels monitored periodically to prevent a missed diagnosis of vitamin B12 deficiency.
Malabsorptive states need correction of underlying disease and vitamin supplementation.
Folate deficiency due to certain drugs may need modification of drug therapy.
packed red blood cell transfusion
Treatment recommended for ALL patients in selected patient group
Folic acid replacement therapy and packed red blood cell transfusion should be started simultaneously in cases where there is anaemia and associated heart failure.
Blood should be transfused slowly, with the use of diuretics to avoid volume overload.
Patients should be monitored for hypokalaemia following the commencement of folic acid therapy for severe megaloblastic anaemia.[50]Selhub J, Jacques PF, Dallal G, et al. The use of blood concentrations of vitamins and their respective functional indicators to define folate and vitamin B12 status. Food Nutr Bull. 2008 Jun;29(2 suppl):S67-73. http://www.ncbi.nlm.nih.gov/pubmed/18709882?tool=bestpractice.com Serum potassium should be replaced as needed.
Primary options
furosemide: children: 1-2 mg/kg intravenously/intramuscularly every 6-12 hours initially, increase according to response, maximum 6 mg/kg/dose, or 0.5 to 2 mg/kg orally every 6-12 hours initially, increase according to response, maximum 6 mg/kg/dose; adults: 20-80 mg orally every 6-8 hours initially, increase according to response, maximum 600 mg/day, or 20-40 mg intravenously/intramuscularly every 6-12 hours initially, increase according to response, maximum 80 mg/dose
congenital: hereditary folate malabsorption
folinic acid
Hereditary folate malabsorption is treated with parenteral folinic acid.
High-dose oral folinic acid may be considered in select cases.
Primary options
folinic acid: consult specialist for guidance on dose
congenital: methylenetetrahydrofolate reductase (MTHFR) polymorphisms
folic acid
MTHFR polymorphisms should be treated with daily oral folic acid to ensure optimum protection against low folate status.
Primary options
folic acid: children and adults: 0.4 mg orally once daily
congenital: cerebral folate transport deficiency
folinic acid
Cerebral folate transport deficiency is treated with high doses of folinic acid, which can bypass the transport defect across the blood-brain barrier.[55]Russel A, Statter M, Abzug S. Methionine-dependent formiminoglutamic acid transferase deficiency: human and experimental studies in its therapy. Hum Hered. 1977;27:205.
Primary options
folinic acid: consult specialist for guidance on dose
Choose a patient group to see our recommendations
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer
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