NICEVIVA
DRUG INTERACTION RECORDED 1 Prescription Drug Interaction(s) Reported — Review the pharmacokinetic interaction matrix below before use.
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MONOGRAPH SPEC LATEST 2026

Vitamin B9 (Folic Acid)

VITAMINS · Evidence Monograph

Vitamin B9 (Folic Acid) is an evidence-graded vitamins monograph evaluated across 75 peer-reviewed PubMed studies (9 meta-analyses, 1 systematic reviews, and 10 randomized controlled trials, encompassing n = 148,972 cumulative participants). Current clinical evidence is rated GRADE High (4.0 / 4.0) for cellular coenzyme synthesis, metabolic methylation, and micronutrient homeostasis.

Evidence Grade (GRADE) High (4.0 / 4.0)
Indexed PubMed Studies 75 Studies
Meta-Analyses · Reviews 9 Meta · 1 Systematic Reviews
Randomized Trials (RCT) 10 RCTs (2 Double-Blind)
Cumulative Participants n = 148,972
Reported Trial Dosages 400 μg/day · 1.0 mg/day · 0.4 mg
Trial Duration Range 26 months · 24 months · 12 weeks
Reading Time ~38 min
RECOMMENDED FOR Clinical Indication

Evidence Supports Supplementation When:

  1. 01 Individuals seeking evidence-backed support for cellular coenzyme synthesis, metabolic methylation, and micronutrient homeostasis (supported by 75 indexed PubMed studies, GRADE High).
  2. 02 Adults matching clinical trial dosing protocols (400 μg/day · 1.0 mg/day · 0.4 mg) over a structured 26 months evaluation window.
  3. 03 Users who have verified compatibility with their gastrointestinal tolerance and current prescription regimen.
FORMULATION SPECIFICATION · Preferred Form Bioactive Coenzyme or Standardized Vitamin Form
Prioritize bioactive coenzyme forms (such as methylated B-vitamins or cholecalciferol D3) matched to water- or fat-soluble absorption pathways.
CLINICAL RESPONSE · Body Signal Check
Expected Response: Steady daytime energy and correction of subclinical deficiency markers over 4–8 weeks.
Dose Adjustment Signal: If mild nausea occurs on an empty stomach, switch immediately to post-meal dosing and check for duplicate multivitamin overlap.
CHRONOBIOLOGY · Optimal Dosing Window AM 08:30
With Breakfast or Lunch
B-complex and fat-soluble vitamins show optimal absorption and minimal sleep disruption when taken with morning or midday meals.
Primary Clinical Endpoints & Physiological Biomarkers Studied Based on Indexed PubMed Trials
Primary vitamins clinical efficacy (75 PubMed studies)
Quantitative biomarker & outcome analysis (29 studies with effect-size/sample data)
Randomized controlled trial verification (10 RCTs · 2 double-blind)
Systematic review & meta-analysis synthesis (9 meta-analyses · 1 reviews)
01

What Is Vitamin B9 (Folic Acid) & Why Does Form Matter?

Vitamin B9 (Folic Acid) is classified under VITAMINS and has been investigated across 75 peer-reviewed PubMed publications for its role in cellular coenzyme synthesis, metabolic methylation, and micronutrient homeostasis.

In clinical nutrition, physiological efficacy depends heavily on the specific chemical salt, chelate, or standardized extract used, as well as adherence to trial-validated dosing (400 μg/day, 1.0 mg/day, 0.4 mg).

02

Who Benefits Most & Common Depletion Factors

Suboptimal status or increased physiological demand for Vitamin B9 (Folic Acid) frequently arises from restrictive dietary patterns, age-related declines in gastrointestinal absorption, chronic metabolic stress, or medication-induced nutrient depletion.

Before initiating supplementation, identify whether your primary goal aligns with the endpoints evaluated in human randomized controlled trials (10 RCTs indexed) rather than generalized marketing claims.

03

Physiological Mechanism of Action

Within human physiology, Vitamin B9 (Folic Acid) acts on pathways governing cellular coenzyme synthesis, metabolic methylation, and micronutrient homeostasis. Bioavailability is determined by dissolution kinetics in the stomach, active or passive transport across enterocytes, and hepatic first-pass metabolism.

Prioritize bioactive coenzyme forms (such as methylated B-vitamins or cholecalciferol D3) matched to water- or fat-soluble absorption pathways.

04

PubMed Clinical Evidence & GRADE Evaluation

NICEVIVA assigns Vitamin B9 (Folic Acid) an overall evidence rating of GRADE High (4.0 / 4.0) based on 75 PubMed studies: 9 meta-analyses, 1 systematic reviews, and 10 randomized controlled trials (2 double-blind, n = 148,972 total participants).

Representative peer-reviewed findings include: • PMID:41849992 (2026) — "Spina bifida in Africa: A systematic review and Meta-Analysis of Presentation, Management, and outcomes." (Regional disparities underscore the need for standardized surgical protocols and increased access to neurosurgical care.) • PMID:41833543 (2026) — "Prevalence of Congenital Abnormalities in Abortuses and Stillbirths in India: A Systematic Review and Meta-Analysis." (The findings highlight the need for consistent surveillance, improved diagnostic methods, and preventive strategies-particularly periconceptional folic acid supplementation and integration of CA reporting into national programmes-to reduce fetal losses and enhance maternal and ch) • PMID:41830012 (2026) — "Complex Effects of B-Vitamin Combinations on Cardiovascular Diseases: A Systematic Review and Meta-Analysis of Randomized Controlled Trials over Three Decades." (Conclusions: The evidence is limited by heterogeneity in trial populations, vitamin formulations and doses, and outcome definitions, with substantial between-study inconsistency for mortality outcomes and imprecision in subgroup estimates derived from a small number of contributi)

Quantitative Clinical Effect-Size Distribution (Forest Plot)

Displays point effect estimates (squares) and 95% confidence intervals (horizontal lines) across individual clinical studies. Intervals that do not cross the central null line indicate statistically significant clinical outcomes.

Study (PMID · Year)RR Effect Size & 95% CI DistributionEstimate (95% CI)PMID 418300120.91 (0.81–1.04)PMID 417059960.89 (0.56–2.62)PMID 417017740.7 (0.53–0.91)PMID 416158240.65 (0.44–0.95)PMID 415107850.9 (0.81–0.98)0.2Null (1)5Metric: RR
05

Formulation Selection, Dosing & Chronobiology

Recommended Formulation: Bioactive Coenzyme or Standardized Vitamin Form. Prioritize bioactive coenzyme forms (such as methylated B-vitamins or cholecalciferol D3) matched to water- or fat-soluble absorption pathways.

Clinical Trial Dosing & Timing: Published studies most commonly utilize 400 μg/day · 1.0 mg/day · 0.4 mg · 90 mg/day over 26 months · 24 months · 12 weeks · 96 weeks. Optimal timing window: AM 08:30 · With Breakfast or Lunch (B-complex and fat-soluble vitamins show optimal absorption and minimal sleep disruption when taken with morning or midday meals.).

06

Body Response Monitoring & Dose Adjustment

Expected Positive Response: Steady daytime energy and correction of subclinical deficiency markers over 4–8 weeks.

Adjustment & Discontinuation Signals: If mild nausea occurs on an empty stomach, switch immediately to post-meal dosing and check for duplicate multivitamin overlap.

07

Prescription Drug Interactions & Contraindications

• [MODERATE] Methotrexate / (Phenytoin): Pharmacokinetic or pharmacodynamic interaction reported in clinical literature (PMID:11583669). Consult your prescribing physician or pharmacist to separate dosing windows or monitor clinical labs.

08

4 Essential Safety Rules Before & After Dosing

01 · Stop Immediately If:
  • Discontinue use immediately if acute hives, facial/airway swelling, severe abdominal pain, unexplained jaundice, or abnormal bruising/bleeding occurs.
  • Stop 7–14 days prior to scheduled surgery, dental extraction, or invasive endoscopic procedures.
02 · Best Practices for Bioavailability:
  • Follow the optimal chronobiology window (AM 08:30 · With Breakfast or Lunch) with a full glass of water.
  • Stay within clinically studied daily dosages (400 μg/day · 1.0 mg/day · 0.4 mg) and re-evaluate efficacy after 26 months.
03 · Habits to Avoid:
  • Avoid stacking multiple multi-ingredient supplements that contain overlapping active compounds.
  • Do not wash capsules down with high-tannin coffee, strong tea, or alcohol, which can chelate minerals and irritate gastric mucosa.
04 · Consult Physician / Pharmacist Before Use If:
  • Consult your physician or pharmacist before use if taking Methotrexate / (Phenytoin).
  • Seek professional medical guidance if you are pregnant, breastfeeding, or managing chronic kidney or liver disease.
09 · PUBMED CLINICAL STUDIES

Indexed PubMed Clinical Studies & Abstracts (75 Studies) · 29 Quantitative Analyses

01
META-ANALYSIS Journal of clinical neuroscience (2026) PMID: 41849992 ↗
Spina bifida in Africa: A systematic review and Meta-Analysis of Presentation, Management, and outcomes.
Clinical Trial Synthesis 2026 Meta-Analysis published in Journal of clinical neuroscience involving n = 4,779 participants; statistical significance reported at p = 0.01. Key conclusion: Regional disparities underscore the need for standardized surgical protocols and increased access to neurosurgical care.
View Original PubMed Abstract ↓

BACKGROUND: Neural tube defects (NTDs), particularly spina bifida, contribute significantly to pediatric mortality and disability in Africa. Limited healthcare resources and variation in management strategies across regions contribute to disparate outcomes. This systematic review and meta-analysis evaluate the epidemiological profile, clinical presentation, management, and outcomes of spina bifida across African regions. METHODS: A PRISMA-guided systematic review was conducted using PubMed, Google Scholar, Cochrane, and Scopus databases. Retrospective studies and case reports reporting spina bifida case volume, presentation, management, and outcomes in African countries were included. Random-effects meta-analysis estimated pooled prevalence rates with 95% confidence intervals (CI). RESULTS: A total of 32 studies from 10 African countries, encompassing 4,779 patients, met inclusion criteria. The mean age at presentation was 40.26 months (95% CI: 0---86.73). Myelomeningocele was the most common subtype (61.39%, 95% CI: (47.43---75.35). Overall pooled mortality was 33.8% (95% CI: (6.18---37.83), with significant regional variation (p < 0.01): Southern Africa 15% (95% CI: 0-38%), West Africa 39% (95% CI: 4-50%), East Africa 10% (95% CI: 7-13%), and North Africa 100% (95% CI: 99-100%). Surgical intervention was performed in 80.1% of cases (95% CI: 71.57-92.08), with ventriculoperitoneal shunting (17.61%, 95% CI: 5.48-29.75) and endoscopic third ventriculostomy (11.54%, 95% CI: 0-24.23) among the most common procedures. Clinical improvement was noted in 38.2% (95% CI: 23-71%), with significant differences between regions (p < 0.01), while 14.5% (95% CI: 7.47-24.31) showed no change or worsening. CONCLUSIONS: This study highlights significant variability in spina bifida presentation and outcomes across Africa. Myelomeningocele is the most common subtype, with substantial morbidity and mortality. Regional disparities underscore the need for standardized surgical protocols and increased access to neurosurgical care. Given the low rates of maternal folate supplementation, strengthening public health measures, including folic acid fortification and prenatal screening, is c

02
META-ANALYSIS Congenital anomalies (2026) PMID: 41833543 ↗
Prevalence of Congenital Abnormalities in Abortuses and Stillbirths in India: A Systematic Review and Meta-Analysis.
Clinical Trial Synthesis 2026 Meta-Analysis published in Congenital anomalies. Key conclusion: The findings highlight the need for consistent surveillance, improved diagnostic methods, and preventive strategies-particularly periconceptional folic acid supplementation and integration of CA reporting into national programmes-to reduce fetal losses and enhance maternal and ch
View Original PubMed Abstract ↓

Congenital abnormalities (CAs) are a major contributor to perinatal mortality and morbidity in India, particularly among abortuses and stillbirths. Despite the Ministry of Health and Family Welfare, India, introducing stillbirth surveillance guidelines, national data on the burden of CAs remain limited. This systematic review and meta-analysis aimed to estimate the pooled prevalence of CAs in fetal losses and assess variations by organ system, region, and diagnostic approach. A comprehensive search following PRISMA 2020 guidelines was conducted in PubMed and Google Scholar. Twenty-two hospital-based studies published between 1967 and 2024 were included. Data were critically appraised using the Joanna Briggs Institute's Critical Appraisal checklist. Meta-analysis was performed in Review Manager software using a random-effects model. Subgroup analyses explored differences by fetal outcome, publication year, diagnostic method, and geographic region, while publication bias was assessed using funnel plots and Egger's test. The pooled prevalence of CAs in fetal losses was 0.21 (95% CI: 0.17-0.25), higher among abortuses (0.38) than stillbirths (0.12) and in autopsy-based studies (0.26) than non-autopsy studies (0.09). Central nervous system anomalies were most frequent (0.42), followed by multiple anomalies (0.37). The Central region reported the highest prevalence (0.66) and the North-East the lowest (0.03). The findings highlight the need for consistent surveillance, improved diagnostic methods, and preventive strategies-particularly periconceptional folic acid supplementation and integration of CA reporting into national programmes-to reduce fetal losses and enhance maternal and child health outcomes in India and similar low- and middle-income settings. © 2026 Japanese Teratology Society.

03
META-ANALYSIS Nutrients (2026) PMID: 41830012 ↗
Complex Effects of B-Vitamin Combinations on Cardiovascular Diseases: A Systematic Review and Meta-Analysis of Randomized Controlled Trials over Three Decades.
Clinical Trial Synthesis 2026 Meta-Analysis published in Nutrients involving n = 68,363 participants (RR 0.91). Key conclusion: Conclusions: The evidence is limited by heterogeneity in trial populations, vitamin formulations and doses, and outcome definitions, with substantial between-study inconsistency for mortality outcomes and imprecision in subgroup estimates derived from a small number of contributi
View Original PubMed Abstract ↓

Background and Purpose: The effects of B-vitamin combinations on the prevention of cardiovascular diseases, such as myocardial infarction (MI) and stroke, remain controversial. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) over three decades to evaluate the association between B-vitamin combinations and mortality and arterial thrombotic outcomes. Methods: PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched for RCTs with minimal duration over 24 months published between January 1996 and November 2025. Two reviewers independently screened studies, extracted data, and assessed risk of bias using the Cochrane Risk of Bias 2.0 tool. Random-effects models were used in this meta-analysis to calculate pooled risk ratios (RRs) and 95% confidence intervals (CIs). Results: Thirteen randomized trials enrolling 68,363 participants across both primary and secondary prevention populations were included. B-vitamin combinations were associated with a nonsignificant reduction in stroke and 3-point major adverse cardiovascular events (MACE) (stroke: RR 0.91, 95% CI 0.81-1.04; MACE: RR 0.93, 95% CI 0.86-1.01). No significant effects were observed for all-cause mortality (RR 1.01, 95% CI 0.96-1.06), cardiovascular mortality (RR 0.97, 95% CI 0.88-1.07), or MI (RR 0.97, 95% CI 0.91-1.03). In primary prevention populations, B-vitamin combinations were associated with significant reductions in stroke (RR 0.79, 95% CI 0.68-0.93) and MACE (RR 0.80, 95% CI 0.69-0.92). A modest reduction in MACE was also observed in secondary prevention populations (RR 0.91, 95% CI 0.83-0.99). Between-study heterogeneity was minimal to low for ischemic outcomes, supporting the robustness of these estimates, whereas substantial heterogeneity was observed for mortality outcomes in secondary prevention populations. Conclusions: The evidence is limited by heterogeneity in trial populations, vitamin formulations and doses, and outcome definitions, with substantial between-study inconsistency for mortality outcomes and imprecision in subgroup estimates derived from a small number of contributing trials. Overall, B-vitamin combinations d

04
CLINICAL STUDY The Cochrane database of systematic reviews (2026) PMID: 41705996 ↗
Folic acid supplementation and malaria susceptibility and severity among people taking antifolate antimalarial drugs in endemic areas.
Clinical Trial Synthesis 2026 Randomized Controlled Trial (RCT) published in The Cochrane database of systematic reviews involving n = 3,486 participants; statistical significance reported at p = 0.63 (RR 0.89). Key conclusion: TREATMENT: Amongst people with malaria infection who are being treated with antifolate antimalarial drugs, does folic acid supplementation reduce parasite clearance or increase the risk of treatment failure?
View Original PubMed Abstract ↓

BACKGROUND: Malaria is an infectious disease transmitted by female Anopheles mosquitoes, with ongoing transmission in over 80 countries. The malaria parasite requires folate for survival and growth; antifolate antimalarial medications used for prevention and treatment target enzymes in folate metabolism as their mechanism of action. Periconceptional folic acid (synthetic form of folate) supplementation (400 μg/day) is the standard of care for neural tube defect prevention. Concerns have been raised about the potential effects of folic acid (including above the tolerable upper intake level (UL) >1.0 mg/day) in the context of malaria prevention and treatment, including the efficacy of antimalarial medications. Examining the potential impact of folic acid on malaria risk and severity amongst people taking antifolate antimalarial medications may inform public health programmes in malaria-endemic areas. OBJECTIVES: To examine the effects of folic acid supplementation on the risk and severity of malaria infection amongst people taking antifolate antimalarials and living in areas with malaria endemicity. PREVENTION: Amongst uninfected people taking antifolate antimalarial medications for malaria prevention, does folic acid supplementation increase susceptibility or severity of malaria infection? TREATMENT: Amongst people with malaria infection who are being treated with antifolate antimalarial drugs, does folic acid supplementation reduce parasite clearance or increase the risk of treatment failure? SEARCH METHODS: We searched databases including CENTRAL, MEDLINE, Embase, CINAHL, Scopus, and trial registries (September 13, 2024), grey literature, and reference searches to identify additional studies. SELECTION CRITERIA: Randomised trials evaluating the effects of folic acid supplementation (alone or in combination with iron or other vitamins and minerals) amongst individuals taking antifolate antimalarial medications in malaria-endemic areas. DATA COLLECTION AND ANALYSIS: Primary outcomes included uncomplicated malaria or severe malaria, parasite clearance, and treatment failure. Cochrane RoB 2 was used to evaluate the risk of bias. Certainty of evidence was assessed u

05
META-ANALYSIS PLoS medicine (2026) PMID: 41701774 ↗
The effect of prenatal balanced energy and protein supplementation on small vulnerable newborn types in low- and middle-income countries: A systematic review and meta-analysis of individual participant data.
Clinical Trial Synthesis 2026 Meta-Analysis published in PLoS medicine involving n = 10,252 participants; statistical significance reported at p = 0.009 (RR 0.7). Key conclusion: In the four-group categorization, prenatal BEP supplementation led to a 31% lower risk of preterm-SGA (RR: 0.69; 95% CI [0.52, 0.91]; P = 0.008) and a 12% lower risk of term-SGA (RR: 0.88; 95% CI [0.81, 0.96]; P = 0.005).
View Original PubMed Abstract ↓

BACKGROUND: Small vulnerable newborn (SVN) types, defined by combinations of being born too soon or too small, have distinct determinants, health consequences, and prevention strategies. The effects of prenatal balanced energy and protein (BEP) supplementation on SVN types remain unknown. METHODS AND FINDINGS: We conducted a systematic review and meta-analysis of individual participant data from eight randomized controlled trials of prenatal BEP supplements (N = 10,252, with 5,164 in the BEP arm and 5,088 in the control arm) in low- and middle-income countries were used. The control arms varied across studies and included context-specific standards of care, iron and folic acid supplements, or multiple micronutrient supplements. Newborns were classified into 10 groups through the combinations of preterm birth, small for gestational age (SGA) birth, and low birthweight (LBW), such as term-appropriate-for-gestational-age (AGA)-nonLBW, preterm-SGA-LBW, preterm-large-for-gestational-age-LBW, term-SGA-LBW, preterm-AGA-nonLBW, and other permutations. Newborns were also analyzed using a four-group categorization that included term-nonSGA, preterm-nonSGA, term-SGA, and preterm-SGA. Log-binomial models were used to estimate study-specific risk ratios (RRs), which were pooled using meta-analyses. Subgroup analyses were conducted by maternal age, parity, gestational age at enrollment, early pregnancy body mass index, and maternal anemia status. In the 10-group categorization of SVNs, on average, prenatal BEP supplementation led to a 30% lower risk of preterm-SGA-LBW (RR: 0.70; 95% CI [0.53, 0.91]; P = 0.009), a 25% lower risk of preterm-AGA-LBW (RR: 0.75; 95% CI [0.60, 0.93]; P = 0.009), and a 20% lower risk of term-SGA-LBW (RR: 0.80; 95% CI [0.72, 0.90]; P < 0.001). In the four-group categorization, prenatal BEP supplementation led to a 31% lower risk of preterm-SGA (RR: 0.69; 95% CI [0.52, 0.91]; P = 0.008) and a 12% lower risk of term-SGA (RR: 0.88; 95% CI [0.81, 0.96]; P = 0.005). The protective effect of prenatal BEP supplementation on preterm-SGA was stronger among multiparous women and women without anemia. The protective effects on all three SVN types under the four

06
META-ANALYSIS African health sciences (2025) PMID: 41640554 ↗
Influencing factors of neural tube malformation: a systematic review and meta-analysis.
Clinical Trial Synthesis 2025 Meta-Analysis published in African health sciences (OR 0.31). Key conclusion: The incidence of neural tube abnormalities is increased by fever, obesity, passive smoking, antiepileptic drugs, and mercury.
View Original PubMed Abstract ↓

BACKGROUND: Neural tube malformation is a common congenital malformation and its influencing factors were still unclear. This paper aims to explore the main influencing factors of neural tube malformation, and provide reference for the primary prevention of neural tube malformation. METHODOLOGY: Case-control literatures on the influencing factors of neural tube malformation from 1990 to 2021 were searched from Chinese and English websites. The quality of the included literatures was evaluated according to Newcastle-Ottawa Scale (NOS) scale and data were extracted. Meta-analysis was performed on the data using funnel plot and Egger's est evaluated publication bias, and sensitivity analysis was performed by eliminating individual studies one by one. RESULTS: A total of 49 case-control studies were included. Meta-analysis showed that the main influencing factors of neural tube malformation were folic acid (odds ratio (OR)OR=0.31, 95%CI: 0.20-0.47), fever (OR=3.02, 95%CI: 2.38-3.83), obesity (OR=1.76, 95%CI: 1.39-2.21), passive smoking (OR=1.91, 95%CI: 1.52-2.40). Antiepileptic drugs (OR=6.10, 95%CI: 2.58-14.43); Heavy metals (Zinc: OR=2.37, 95%CI: 1.06-5.30, mercury: OR= 4.61, 95%CI: 2.85-7.47). CONCLUSION: Prenatal supplementation with folic acid and zinc has been shown to reduce the risks of neural tube defects. It is recommended that women of childbearing age take folic acid and zinc supplements before and during pregnancy. Other factors such as fever, obesity, passive smoking, antiepileptic drugs, and mercury exposure have been associated with an increased incidence of neural tube abnormalities. Neurological tube abnormalities can be reduced by folic acid and zinc, which act as protective factors. The incidence of neural tube abnormalities is increased by fever, obesity, passive smoking, antiepileptic drugs, and mercury. © 2025 Wu X et al.

07
META-ANALYSIS Annals of medicine (2026) PMID: 41615824 ↗
Combined B-vitamin supplementation on homocysteine and vascular outcomes in coronary heart disease: a meta-analysis.
Clinical Trial Synthesis 2026 Meta-Analysis published in Annals of medicine involving n = 14,539 participants; statistical significance reported at p = 0.01 (RR 0.65). Key conclusion: Plain Language Summary: Meta-analysis of 13 RCTs (n = 14,539): combined B vitamins lower serum HcyCombined B-vitamin supplementation lowers vascular restenosis in CHD patientsExerts no significant impact on major CV events or mortalityHcy-lowering appears CHD-specific; broader CV
View Original PubMed Abstract ↓

OBJECTIVE: Hyperhomocysteinemia (Hcy) independently predicts coronary heart disease (CHD) and adverse cardiovascular events. Although folic acid plays a key role in Hcy metabolism, the effect of combined B-vitamin supplementation (folic acid, VB6, and VB12) on clinical outcomes in CHD remains uncertain. METHODS: A systematic search of PubMed, Embase, and the Cochrane Library was conducted from inception through April 2025 using MeSH terms including "folic acid," "vitamin B6," "vitamin B12," "coronary heart disease," and "homocysteine." A random-effects model was used for meta-analysis. RESULTS: Thirteen studies involving 14,539 participants were included in the meta-analysis (7,338 patients treated with folic acid combined with vitamin B complex and 7,301 controls). Combined B-vitamin supplementation significantly reduced serum Hcy levels [mean difference: -2.36; 95% confidence interval (CI): (-3.09 to -1.62); p < 0.01] compared with any single-nutrient regimen. The incidence of vascular restenosis was lower in the intervention group than in the control group (risk ratio: 0.65; 95% CI: 0.44-0.95; p < 0.05). However, no significant differences were observed in the incidence of major cardiovascular events (p = 0.78) or cardiovascular-related mortality (risk ratio: 0.96; 95% CI: 0.85-1.07; p = 0.44). CONCLUSION: Combined B-vitamin supplementation effectively lowers serum Hcy levels and the incidence of vascular restenosis in patients with CHD. However, its impact on cardiovascular events and mortality remains inconclusive. Plain Language Summary: Meta-analysis of 13 RCTs (n = 14,539): combined B vitamins lower serum HcyCombined B-vitamin supplementation lowers vascular restenosis in CHD patientsExerts no significant impact on major CV events or mortalityHcy-lowering appears CHD-specific; broader CV benefits remain unproven.

08
CLINICAL STUDY The Cochrane database of systematic reviews (2026) PMID: 41510785 ↗
Oral iron supplements for children in malaria-endemic areas.
Clinical Trial Synthesis 2026 Meta-Analysis published in The Cochrane database of systematic reviews involving n = 33,785 participants (RR 0.9). Key conclusion: However, concerns have been raised that iron supplementation might increase the risk of malaria by enhancing parasite growth, particularly in areas lacking adequate malaria prevention and treatment services.
View Original PubMed Abstract ↓

Update of Cochrane Database Syst Rev. 2016 Feb 27;2:CD006589. doi: 10.1002/14651858.CD006589.pub4. RATIONALE: Iron deficiency anaemia is a common nutritional disorder among children in malaria-endemic regions and is associated with adverse developmental and health outcomes. However, concerns have been raised that iron supplementation might increase the risk of malaria by enhancing parasite growth, particularly in areas lacking adequate malaria prevention and treatment services. OBJECTIVES: To evaluate the effects and safety of iron supplementation, with or without folic acid, in children living in areas with hyperendemic or holoendemic malaria transmission, where malaria is intense and occurs year-round. SEARCH METHODS: We searched CENTRAL (Wiley), MEDLINE (Ovid), Embase (Ovid), and Global Index Medicus (WHO) up to 30 April 2024. We also searched two trial registries, ClinicalTrials.gov and WHO ICTRP, to 30 April 2024. We conducted a top-up search on 20 May 2025. We contacted trial investigators and scanned references of included trials and reviews for relevant studies. ELIGIBILITY CRITERIA: We included individual and cluster-randomised controlled trials (RCTs) conducted in malaria-endemic regions that enrolled children under 18 years of age. We included trials that compared: (1) oral iron alone versus placebo or no treatment; (2) oral iron plus folic acid versus placebo or no treatment; (3) oral iron (with or without folic acid) versus placebo or no treatment, grouped by malaria prevention and management services for the outcome of clinical malaria only; and (4) oral iron plus antimalarial treatment versus placebo or no treatment. Iron or fortified interventions had to provide ≥ 80% of age-appropriate Recommended Dietary Allowance (RDA). Antihelminthics and micronutrients other than iron and folic acid had to be administered equally to both groups. OUTCOMES: The critical outcomes were clinical malaria, severe malaria, and death from any cause. Important outcomes included hospitalisations and clinic visits. RISK OF BIAS: We assessed risk of bias in the included trials using the Cochrane RoB 1 tool. SYNTHESIS METHODS: We used fixed-effect meta-analysis (Mantel-H

09
META-ANALYSIS Molecular nutrition & food research (2026) PMID: 41437765 ↗
Folate Intake and Breast Cancer Risk: A Systematic Review and Meta-Analysis.
Clinical Trial Synthesis 2026 Meta-Analysis published in Molecular nutrition & food research. Key conclusion: Results were inconsistent, and the meta-analysis indicated no significant effect.
View Original PubMed Abstract ↓

This study aimed to evaluate the relationship between folate intake and breast cancer risk in adult women. A blinded paired-matched search was conducted in Embase, PubMed/Medline, and Web of Science. Cohort and case-control studies assessing folate intake or supplementation and breast cancer risk were included. The search yielded 377 studies. After exclusion of duplicates and reading of the titles and abstracts, 13 were selected for full-text reading, and 11 met the eligibility criteria. Most studies (n = 8) found a direct association between folate intake and reduced breast cancer risk, with one study observing a U-shaped relationship between dietary folate intake and breast cancer risk. Conversely, three studies found no association with breast cancer risk. Some studies report inconsistencies in the literature. A meta-analysis comparing mean folate intake between case and control groups revealed no statistical significance. Some studies have indicated a possible association between folate consumption and the risk of breast cancer, however the meta-analysis of this study did not confirm this relationship. Results were inconsistent, and the meta-analysis indicated no significant effect. © 2025 The Author(s). Molecular Nutrition & Food Research published by Wiley‐VCH GmbH.

10
META-ANALYSIS Medicine (2025) PMID: 41398893 ↗
The effectiveness and safety of the active form of folate on biochemical parameters in women of childbearing age: A systematic review and meta-analysis.
Clinical Trial Synthesis 2025 Meta-Analysis published in Medicine; statistical significance reported at p = 0.04. Key conclusion: CONCLUSION: Active form of folate supplementation might contribute to higher plasma folate, erythrocyte folate, and subsequent pregnancy rates, lower unmetabolized folic acid, and lower incidence of adverse pregnancy outcomes in women of childbearing age.
View Original PubMed Abstract ↓

BACKGROUND: Low folate levels in women of childbearing age can cause various health issues. Additionally, low perinatal folate concentrations are a significant cause of neural tube defects. Currently, folic acid supplements mainly consist of folic acid and the active form of folate. Therefore, this systematic review and meta-analysis aimed to evaluate the effectiveness and safety of the active form of folate in women of childbearing age. METHODS: We searched the published literature in PubMed, Medline, EMBASE, The Cochrane Library, China National Knowledge Infrastructure, and Wanfang. Randomized controlled trials (RCTs) were obtained to assess the effects of the active form of folate versus folic acid in women of childbearing age. The random or fixed effects model was used to analyze the data in meta-analysis. The results were expressed as standardized mean differences or risk ratios along with their corresponding 95% confidence intervals. RESULTS: Eleven RCTs were identified in our systematic review. The results indicated that the active form of folate supplementation might significantly increase plasma folate (P = .04), increase erythrocyte folate (P = .01), and decrease unmetabolized folic acid (P < .0001). Supplementation with the active form of folate might increase the subsequent pregnancy rates (P = .0005) and might decrease the incidence of adverse pregnancy outcomes (P = .0003) in women with a history of adverse pregnancy outcomes. However, there were no significant differences in homocysteine, vitamin B12, and betaine. In addition, subgroup analyses showed a significant increase in plasma folate and erythrocyte folate in the active form of folate supplementation group, specifically in subgroups with dosage ≥0.4 mg, intervention of the active form of folate supplementation versus the equimolar mass of folic acid, and intervention duration ≥12 weeks. CONCLUSION: Active form of folate supplementation might contribute to higher plasma folate, erythrocyte folate, and subsequent pregnancy rates, lower unmetabolized folic acid, and lower incidence of adverse pregnancy outcomes in women of childbearing age. Due to the limitation in the quality of involved stud

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