Supplement evidence

003 / 575Vitamin

Folate / folic acid

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The short answer

Preventing neural-tube defects around conception and treating folate deficiency.

Evidence and scope: Established for an indicated use
This status does not grade the ingredient for every goal, outcome, or person.
Important limitation: It is not a general anti-aging supplement for folate-replete adults.
Before deciding: High folic-acid intake can mask vitamin B12 deficiency; pregnancy dosing should follow local guidance.

01 / PRACTICAL GUIDE

Dose, absorption, and combinations

These are indication-specific reference or studied ranges—not a personalized prescription. Start with the objective, then check the form, label, medicines, and health conditions.

Reference range by objective

Meeting usual needs400 mcg DFE/day

Reference or studied range—not a personalized prescription. The product label or a clinician may specify a different dose.

Dose source ↗

Pregnancy-related need400–800 mcg/day folic acid around conception unless a clinician specifies otherwise

Reference or studied range—not a personalized prescription. The product label or a clinician may specify a different dose.

Dose source ↗

More is not automatically better. A clinician or product label may specify a different amount.

Absorption / solubilityWater-soluble

Water-soluble or readily water-dispersible. This does not mean excess is always harmless.

How it is commonly taken

May be taken with food; prenatal use should follow local guidance.

Do not combine casually

Do not use high-dose folic acid to bypass evaluation for vitamin B12 deficiency.

Dose and use source ↗

Dose and use links lead to primary or official source material. Search links are discovery tools, not proof that every returned paper applies.

02 / EVIDENCE

What the research says

We keep supportive, mixed, negative, safety, and contextual findings together. The headline never replaces the underlying papers.

5research papers in this ledger

14unique primary studies represented

45,897unique participants represented

These are audited counts for this JIVANA collection, not search-result totals. Participants are counted once when multiple papers use the same cohort; review papers are not added again to participant totals.

Open the research timelineResearch timeline

Entries are ordered by publication year. A study period appears only when the source reports it.

2021

Evidence contextPMID 33338998

Folate fortification and supplementation in prevention of folate-sensitive neural tube defects

Mandatory fortification and recommended supplementation were associated with fewer folate-sensitive neural-tube defects, with larger population change attributed to fortification. This policy evidence is not a randomized supplement-effect estimate.

Published: 2021

Study design and methods

Design: Systematic review of 54 policy and population studies
Population: Populations exposed to mandatory fortification or supplementation policies across multiple countries
Intervention: Mandatory food fortification, recommended supplementation, or both
Outcome: Folate-sensitive neural-tube-defect prevalence, survival, and policy implementation

Open research record ↗

2019

Mixed or qualifiedPMID 30949983

Effect of vitamin B supplementation on cognitive function in the elderly

B-vitamin regimens lowered homocysteine but generally produced no obvious cognitive benefit; two elevated-homocysteine trials had modest, clinically uncertain findings. Because several vitamins were combined, this cannot isolate folate.

Published: 2019n=17,029 participants31 primary studies represented

Study design and methods

Design: Systematic review and meta-analysis of 31 randomized trials
Population: 17,029 older adults with or without cognitive impairment
Intervention: Folic acid, vitamin B12, vitamin B6, or combinations versus placebo
Outcome: Cognitive decline and cognitive-test performance

Open research record ↗

2015

Supports a specific usePMID 26662928

Effects and safety of periconceptional oral folate supplementation for preventing birth defects

Periconceptional folate substantially reduced neural-tube defects. Evidence for other birth defects and for choosing among doses or formulations was less certain; timing around conception is central to the established benefit.

Published: 2015n=7,391 participants5 primary studies represented

Study design and methods

Design: Cochrane systematic review of five randomized or quasi-randomized trials
Population: 7,391 women, including 2,033 with a previous neural-tube-defect-affected pregnancy
Intervention: Folic acid started before conception and continued in early pregnancy, alone or with other micronutrients
Outcome: First occurrence and recurrence of neural-tube defects and other birth outcomes

Open research record ↗

2010

Does not support the tested claimPMID 20937919

Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and mortality

Homocysteine fell by about 25%, but major vascular events, cancer, and mortality did not. Improving a biomarker did not translate into clinical prevention in these higher-risk populations.

Published: 2010Duration: Median 5 yearsn=37,485 participants8 primary studies represented

Study design and methods

Design: Individual-participant-data meta-analysis of eight large randomized trials
Population: 37,485 adults at increased cardiovascular risk
Intervention: Folic-acid-based B-vitamin regimens versus placebo
Outcome: Major vascular events, cancer, and cause-specific and all-cause mortality

Open research record ↗

2007

Safety signalPMID 17551129

Folic acid for the prevention of colorectal adenomas

Folic acid did not prevent recurrent colorectal adenomas. Later follow-up raised concern about advanced or multiple lesions, so milligram-dose folic acid should not be framed as cancer prevention.

Published: 2007Duration: Two surveillance cycles over 6–8 yearsn=1,021 participants

Study design and methods

Design: Multicenter randomized, double-blind, placebo-controlled factorial trial
Population: 1,021 adults with a recent colorectal adenoma
Intervention: Folic acid 1 mg/day or placebo, with a separate aspirin randomization
Outcome: Recurrent adenomas, advanced lesions, and adverse outcomes

Open research record ↗

Unscreened discovery appendix—not evidence4,155 candidate publicationsSearch run: Aug 21, 2026

Complete for the displayed PubMed query at the search timestamp—not for all databases or every possible synonym. Candidates can be irrelevant, duplicate the same study, or report negative findings. They are never summed as evidence or participants until screened.

03 / SOURCES

Start with the source material

Official evidence overviewNIH Office of Dietary Supplements Live PubMed discovery searchNational Library of Medicine

The live search is for discovery only. Search-result counts change and are not included in the audited totals above.

Recent PubMed discovery recordsDirect links to the first 12 records returned by the reproducible search. These are discovery candidates—not reviewed summaries or a count of supportive findings.

04 / EXPERT CONTEXT

Expert context—not evidence

Expert positions are dated context—not scientific evidence. They never raise the evidence status or become consensus by repetition.

No direct, source-verified endorsement is currently recorded. Research authorship or discussion alone is not treated as endorsement.