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📰Read the full Folate evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ Every woman of childbearing potential — 400 µg/day folic acid regardless of pregnancy plans (50% of pregnancies are unplanned) [3]
⚠ Prior NTD-affected pregnancy — 4 mg/day folic acid for subsequent pregnancies [6]
⚠ Megaloblastic anemia in elderly — check B12 BEFORE starting folate (masking risk) [1]
⚠ Patient on methotrexate for rheumatoid arthritis — folic acid supplementation reduces toxicity without reducing efficacy [2]
⚠ MTHFR 677TT + elevated homocysteine — L-5-MTHF + riboflavin may be more effective than folic acid alone [4]
🥗 Food first — build your daily 400 mcg DFE
Check the foods you regularly eat — the bar fills toward your daily target.
Beef liver, cooked (85 g)215 µg DFE
Spinach, cooked (125 mL)131 µg DFE
Black-eyed peas, cooked (170 g)105 µg DFE
Asparagus, cooked (4 spears)89 µg DFE
Brussels sprouts, cooked (125 mL)78 µg DFE
Lettuce, romaine (1 cup)64 µg DFE
Avocado (half)59 µg DFE
Fortified cereal (30 g)100 µg DFE
Check your regular foods above
☑ Risk checker
Pregnancy (increased demand for DNA synthesis) [3]
Chronic alcoholism (impaired absorption and increased excretion) [2]
Malabsorptive conditions (celiac disease, Crohn disease, tropical sprue) [2]
MTHFR 677TT genotype (impaired 5-MTHF production) [4]
Anticonvulsant therapy (phenytoin, carbamazepine, valproate) [2]
Methotrexate and trimethoprim therapy [2]
Sickle cell disease and chronic hemolytic anemias [2]
Hemodialysis (folate is dialyzable) [2]
Select factors
🔬 Lab interpreter
Recommended test
Serum folate
Serum folate
Reference range / target
>7 nmol/L (3 µg/L)
>7 nmol/L (3 µg/L)
Reflects recent dietary intake (past 1–2 weeks). Can be normal despite tissue depletion. Use RBC folate for chronic status [2].
Full lab monitoring ↓⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Folate is the most important preventive nutrient in obstetric medicine — 400 µg/day folic acid before conception prevents approximately 70% of neural tube defects. L-5-MTHF is the preferred form for MTHFR 677TT carriers. Always check B12 status before starting high-dose folic acid in elderly patients to avoid masking pernicious anemia [1] [3] [4].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: Specific dosage data under clinical review
👦 Pediatric: Specific dosage data under clinical review
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Can be taken at any time with or without food. Folic acid from supplements is 85% bioavailable on empty stomach [1].
💊 With food: No specific requirement. Food folate bioavailability is approximately 50% due to polyglutamate form [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['Folic acid', 'common', 'Synthetic form used in fortification and most supplements. Requires enzymatic reduction by DHFR to become active. High bioavailability (85% on empty stomach vs 50% from food folate) [1].'] | Standard | Check label | |
| ['L-5-Methyltetrahydrofolate (5-MTHF)', 'preferred', 'Biologically active form. Bypasses MTHFR enzyme — particularly beneficial for individuals with MTHFR 677C→T polymorphism (up to 25% of some populations) [4]. Does not mask vitamin B12 deficiency [4].'] | Standard | Check label | |
| ['Folinic acid (leucovorin)', '', 'Reduced folate used in clinical settings for methotrexate rescue and 5-FU modulation. Does not require DHFR for activation [2].'] | Standard | Check label |
3 Common questions
Should all women take folic acid? ▼
All women of childbearing potential should take 400 µg/day folic acid, ideally starting at least 1 month before conception. Approximately 50% of pregnancies are unplanned, which is why continuous supplementation (not just when planning pregnancy) is recommended [3]. This single intervention prevents approximately 70% of neural tube defects.
What is the difference between folate and folic acid? ▼
Folate is the natural form found in food (polyglutamate). Folic acid is the synthetic form used in supplements and fortification — it is more stable and has higher bioavailability (85% vs ~50% from food) [1]. L-5-MTHF is the bioactive form available as a supplement, which bypasses the MTHFR enzyme [4].
Can folic acid mask vitamin B12 deficiency? ▼
Yes — this is the basis for the 1,000 µg/day UL. Folic acid can correct the megaloblastic anemia of B12 deficiency while allowing irreversible neurological damage to progress [1]. This is why B12 status should be assessed when high-dose folic acid is prescribed, especially in elderly patients.
Does the MTHFR gene variant mean I need a special supplement? ▼
The MTHFR 677C→T polymorphism reduces MTHFR enzyme activity by 30% (CT) to 70% (TT), impairing conversion of folic acid to active 5-MTHF [4]. Individuals with the TT genotype may benefit from L-5-MTHF (methylfolate) supplements rather than folic acid, and adequate riboflavin (the FAD cofactor for MTHFR) is important [4].
4 Clinical evidence
Strong
Prevention of neural tube defects: periconceptional folic acid supplementation (400 µg/day) reduces NTD risk by approximately 70% [3]. The landmark MRC Vitamin Study (n = 1,817) demonstrated 72% NTD recurrence reduction with 4 mg/day folic acid [6]. Treatment of megaloblastic anemia caused by folate deficiency [2]. Homocysteine reduction: folic acid supplementation at 400–800 µg/day reduces plasma homocysteine by approximately 25% [7]. HIGH
Moderate
Stroke risk reduction: a meta-analysis of 8 randomized trials (n = 16,841) found a 10% reduction in stroke risk with folic acid supplementation, with greater benefit in populations without mandatory fortification [7]. Cognitive decline: China Stroke Primary Prevention Trial (CSPPT, n = 20,702) found folic acid combined with enalapril reduced first stroke by 21% [8]. Autism spectrum disorder: prenatal folic acid supplementation may reduce ASD risk, with strongest evidence for periconceptional use [3]. MODERATE
Insufficient
Cancer prevention: mixed results. Folic acid may protect against colorectal cancer in deficient individuals but could promote growth of pre-existing neoplasms (dual role in one-carbon metabolism) [9]. Cardiovascular disease prevention through homocysteine lowering: the HOPE-2 trial showed reduced stroke but no overall CVD benefit [7]. Depression treatment as adjunct to antidepressants: some positive trials but not consistently replicated [2]. LOW
5 Safety, toxicity & adverse events
Absolute contraindications
✕ Undiagnosed B12 deficiency (folate corrects anemia but masks neurological progression)
Relative
⚠ Methotrexate therapy (folate may reduce efficacy — use only as directed by oncologist)
⚠ Antiepileptic drugs (complex interactions)
🚩 Red flags
● Megaloblastic anemia in elderly — CHECK B12 BEFORE treating with folic acid to avoid masking irreversible neuropathy [1]
● Woman of childbearing age not taking folic acid — NTD prevention opportunity [3]
● Macrocytosis (MCV >100 fL) on routine CBC — evaluate folate and B12 [2]
● Patient on anticonvulsants with macrocytosis — likely folate deficiency from drug-nutrient interaction [2]
● Pancytopenia with megaloblastic bone marrow — distinguish folate vs B12 deficiency (different treatments and prognoses) [2]
6 Interactions
Drug interactions
Methotrexate Major
Mechanism: Methotrexate competitively inhibits DHFR, blocking folic acid activation. In oncology, folate supplementation may reduce efficacy. In rheumatology, folic acid supplementation reduces toxicity without affecting efficacy. [2]
Effect: Without folate: mucositis, pancytopenia, hepatotoxicity. With folate: reduced adverse effects in RA patients. [2]
Action: Rheumatology: folic acid 1 mg/day or folinic acid 5 mg/week. Oncology: folate supplementation only as rescue per protocol [2].
Phenytoin Major
Mechanism: Bidirectional interaction: phenytoin impairs folate absorption and metabolism; folic acid supplementation may increase phenytoin metabolism and reduce serum levels. [2]
Effect: Folate deficiency from phenytoin. Reduced seizure control if folic acid added without dose adjustment. [2]
Action: Monitor phenytoin levels when adding or adjusting folic acid. Supplement folate cautiously with anticonvulsant monitoring [2].
Sulfasalazine Moderate
Mechanism: Competitively inhibits folate transporters (proton-coupled folate transporter) in the intestine. [2]
Effect: Reduced folate absorption. Megaloblastic anemia with chronic use. [2]
Action: Supplement with folic acid 1 mg/day during sulfasalazine therapy [2].
Trimethoprim Moderate
Mechanism: Inhibits bacterial and mammalian DHFR. Prolonged use can impair folate metabolism. [2]
Effect: Megaloblastic anemia possible with prolonged trimethoprim use, especially in patients with marginal folate status. [2]
Action: Folic acid supplementation for prolonged trimethoprim therapy. Folinic acid if hematological toxicity occurs [2].
Supplement synergies
Vitamin B12 · 2.4 µg/day minimum; higher if deficient
B12 is required to regenerate tetrahydrofolate from 5-MTHF (the methyl trap). Without adequate B12, folate is trapped in the 5-MTHF form and unavailable for DNA synthesis [2].
B12 is required to regenerate tetrahydrofolate from 5-MTHF (the methyl trap). Without adequate B12, folate is trapped in the 5-MTHF form and unavailable for DNA synthesis [2].
Riboflavin (B2) · 1.1–1.6 mg/day
FAD (from riboflavin) is the essential cofactor for MTHFR, which produces 5-MTHF. Particularly important in MTHFR 677TT carriers [4].
FAD (from riboflavin) is the essential cofactor for MTHFR, which produces 5-MTHF. Particularly important in MTHFR 677TT carriers [4].
Iron · As per deficiency protocol
Folate and iron deficiencies frequently co-exist in pregnancy. Co-supplementation addresses both simultaneously [3].
Folate and iron deficiencies frequently co-exist in pregnancy. Co-supplementation addresses both simultaneously [3].
7 Regulatory
United States (FDA): Mandatory fortification of enriched cereal grain products (140 µg folic acid per 100 g) since 1998. Dietary supplement. UL: 1,000 µg/day from synthetic folic acid [1]. FDA authorized health claim: 'adequate folic acid may reduce risk of NTDs.'
European Union (EFSA): Authorized health claims for blood formation, homocysteine metabolism, immune function, cell division, maternal tissue growth, and psychological function [10]. No mandatory fortification in most EU countries. UL: 1,000 µg/day [1].
Japan (MHLW): Eligible for Foods with Function Claims. Recommended intake: 240 µg/day; 440 µg/day periconceptional. Fortification is voluntary.
South Korea (MFDS): Registered health functional food ingredient. Approved claims: cell division and blood formation.
8 US supplement products
2,778
on-market products containing Folate (NIH DSLD)
Brands carrying Folate (651)
Click a brand to see its Folate products.
9 Frequently paired with
10 Cite this page
Vancouver: Pkhakadze G. Folate — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Aug 31]. Available from: https://supplement.ge/ingredients/folate/
APA 7th: Pkhakadze, G. (2026). Folate — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/folate/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: March 2027
References: 10 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "Folate — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/folate/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG