Verdict No. 3145 · Search date 2026-09-17 · Methodology v1.0

Oral single-ingredient vitamin B6 and stroke prevention in adults at risk

Name: Verdict 3145 · Oral single-ingredient vitamin B6 and stroke prevention in adults at risk
Creator: Chamgap
Published: 2026-09-17

30-Second Summary

Evidence Grade D · 34 · Safety caution

ChatGPT source review and self-verification · Codex technical integration

Mainly high-risk recent-MI/coronary-angiography adults receiving40mg/day pyridoxine hydrochloride. First-ever stroke, post-stroke recurrence, diagnosed deficiency, PLP/renal strata and other forms remain distinct unscored boundaries.

Caution for peripheral neuropathy and total B6 exposure across products. Australian changes scheduled for2027-06-01 are not already effective or Korean law. Unreported long-term hepatic/renal, pregnancy and pediatric safety remains unconfirmed. Research doses do not instruct self-treatment or changes to standard prevention. [S12–S13]

What the
research showsA stroke-preventive benefit of oral single-ingredient B6 has not been demonstrated. Human trials with genuine monotherapy arms exist, but uncertainty is not proof of zero effect or equivalence.

What the
ads claimThis assessment does not support advertising homocysteine reduction, higher PLP, combined-B-vitamin effects or dietary associations as isolated B6 stroke prevention.

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Four separate assessment dimensions

Effect direction and size	NORVIT pure-arm22/934 versus27/943 and WENBIT20/771 versus19/779 do not establish preventive benefit. Factorial HRs are not relabeled pure-monotherapy effects; neither zero effect nor equivalence is established.
Evidence certainty	Low/limited: stroke is a component/secondary outcome, with sparse events, multiplicity, post-hoc four-arm comparison and unreported pure-arm time-to-event CIs. Same-cohort pooling is not independent replication.
Applicability	Mainly high-risk recent-MI/coronary-angiography adults receiving40mg/day pyridoxine hydrochloride. First-ever stroke, post-stroke recurrence, diagnosed deficiency, PLP/renal strata and other forms remain distinct unscored boundaries.
Safety	Caution: official peripheral-neuropathy warnings and combined exposure from multiple products are retained. Absence of reported serious events is not verified safety; research doses are not dosing instructions.

Supplied calculator B/H/R1/I1/E0/B1/C0 -> D; H and big_hard_rct supply2 strengths, mapped to the fixed34-point anchor. Not a probability, official GRADE rating or individual treatment benefit.

Useful facts when choosing a product

NORVIT/WENBIT: pyridoxine hydrochloride, reported as40mg/day B6; no invented active-mass conversion.
Surgical PLP-monohydrate250/750mg regimens have separate formulation, duration and route; not equivalent doses.

Chamgap Semantic Classification Code

Permanent code issued

S.vitamin-b6-stroke-core-pyridoxine-single.oral.stroke-risk-adults-coronary-history-specific.new-stroke-incidence.stroke-study-specific-placebo-factorial-active-separated

Supplements and nutraceuticals > Core pyridoxine-hydrochloride monotherapy; perioperative PLP separate > Recent-MI/coronary-disease risk adults with mixed previous cerebrovascular history > Oral single-ingredient B6 and new stroke > Actual placebo for core pure arms; factorial and active-low-dose combination contrasts separate > Oral; IV-substitution study is indirect

Technical binding of unchanged ChatGPT D/34, Caution and oral single-B6/stroke/actual-comparator boundaries. The code identifies the intervention and claim; it never contains the evidence grade, score, or safety result.

Download semantic index (JSON) · Codebook v1

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Exact Claim Classification

These independent facets prevent evidence from different forms, routes, populations, effects, and comparators from being mixed.

Intervention class	S · Supplement or nutraceutical
Canonical ingredient or intervention	Vitamin B6
Source or part used	Purified nutrient; botanical species/part not applicable
Formulation or processing	Core pyridoxine-hydrochloride monotherapy; perioperative PLP separate
Route	Oral; IV-substitution study is indirect
Dose	Core research40mg/day B6; not a personal recommendation
Duration	NORVIT median40-month and WENBIT38.4-month follow-up; actual exposure/stopping separate
Population	Recent-MI/coronary-disease risk adults with mixed previous cerebrovascular history
Effect or condition	Oral single-ingredient B6 and new stroke
Primary endpoint	Page: new stroke; distinct from trial primary composites
Comparator	Actual placebo for core pure arms; factorial and active-low-dose combination contrasts separate
Duplicate-detection key	`S\|vitamin-b6\|single-ingredient\|oral\|adults-at-stroke-risk\|incident-stroke\|placebo-or-actual-control`

What the research actually shows

Actual B6-only and placebo arms were verified in NORVIT and WENBIT, with the factorial B6-assignment effects extracted separately. Their pooled reanalysis, surgical PLP trials, combined-B-vitamin trials and dietary/circulating or genetic associations were kept in distinct evidence layers. Pure-arm event counts are available, but a confirmatory time-to-event confidence interval for the isolated monotherapy contrast was not verified.

Why this is classified as D (34)

Supplied calculator B/H/R1/I1/E0/B1/C0 -> D; H and big_hard_rct supply2 strengths, mapped to the fixed34-point anchor. Not a probability, official GRADE rating or individual treatment benefit.

Counterpoint. The complete reason for165 original-table versus181 pooled stroke cases remains unconfirmed. Pure-arm time-to-event CIs, fixed-time risks and MCID are unverified. Access gaps do not establish no effect or no human research.

Rejudgment record. Benefit not demonstrated; not statistical equivalence — Supplied calculator B/H/R1/I1/E0/B1/C0 -> D; H and big_hard_rct supply2 strengths, mapped to the fixed34-point anchor. Not a probability, official GRADE rating or individual treatment benefit.

Stored scoring profile

Claim type	B	B: a clinical efficacy claim about oral single-ingredient B6 and new stroke, not a mechanistic or safety-only statement.
Endpoint	H	Hard endpoint - actual events such as death Case application: H: adjudicated clinical stroke; not PLP, homocysteine or a cardiovascular composite.
Replication	R1	Single confirmatory trial Case application: R1: NORVIT and WENBIT share investigators/funding and differ in acute-MI versus mainly stable-CAD populations; R2 independence is not established. Their CIs include each other's point estimates, so R0 is unwarranted. Surgical PLP, combinations and observational studies are not merged as same-indication RX. This is a conservative vocabulary mapping, not a claim that only one physical trial exists.
Independence	I1	Mixed funding sources Case application: I1: public/nonprofit support coexists with Alpharma product support and some funding; MC-1 II was Medicure-sponsored. Unverified funding is not called independent.
Effect size	E0	Null Case application: E0: under the supplied rubric, a preventive benefit has not been demonstrated in the verified randomized clinical comparisons. This does not mean exactly zero effect, equivalence or ineffectiveness of every form/deficiency treatment. Pure-arm events and factorial CIs are kept separate; no E+ or E- is manufactured.
Precision	C0	The confidence interval leaves room for benefit Case application: C0: factorial CIs 0.54-1.20 and 0.54-1.40, plus the same-cohort pooled CI 0.57-1.02, leave room for benefit. Pure-arm time-to-event CIs are not reported. No verified between-group importance threshold is invented to justify C1 or F.

Stored derived and displayed grades match; this is not a current recalculation or validity check (D).

✓

Review performed and remaining limitations

On2026-09-17, the same author checked original text/tables, denominators, factorial contrasts, arithmetic, grading, bilingual content and fields. This was not independent review; registry histories and some full texts were inaccessible.

The complete reason for165 original-table versus181 pooled stroke cases remains unconfirmed. Pure-arm time-to-event CIs, fixed-time risks and MCID are unverified. Access gaps do not establish no effect or no human research.

Evidence Table

Study	Design	Sample	Funding	Endpoint	Result	Weight
Bonaa et al. Homocysteine lowering and cardiovascular events after acute myocardial infarction. NEJM 2006;354:1578-1588.	Double-blind 2 x 2 factorial RCT with a true B6-only arm	3749 randomized; B6-only 934, placebo 943	Public/nonprofit Norwegian support plus free Alpharma capsules/randomization; disclosed Nycomed consulting. Not wholly manufacturer-only and not fully independent.	Fatal/nonfatal stroke, separate from the primary composite	22/934 versus 27/943; factorial Cox-derived ratio 0.81 (0.54-1.20), not pure-arm HR	Core direct arms; secondary stroke is imprecise and factorial estimand differs
Ebbing et al. Mortality and cardiovascular events in patients treated with homocysteine-lowering B vitamins after coronary angiography. JAMA 2008;300:795-804.	Double-blind 2 x 2 factorial RCT; four-arm comparisons post hoc	3096 randomized,3090 analyzed after 6 consent withdrawals; B6-only 771,placebo 779	Public/university/nonprofit support; Alpharma supplied medication and a limited initial grant and performed randomization; Nycomed consulting disclosed.	Total fatal/nonfatal stroke including hemorrhagic; first event/category	20/771 versus 19/779; factorial HR0.87 (0.54-1.40), P=.56	Core direct arms; mixed stroke history, early termination and unadjusted multiplicity
Ebbing et al. Combined analyses and extended follow-up of two randomized controlled homocysteine-lowering B-vitamin trials. J Intern Med 2010;268:367-382.	Pooled reanalysis and mortality follow-up of the same two RCTs	6837 analyzed;6845 randomizations minus 6 withdrawals and 2 dual-trial participants	Same trial-support program as NORVIT/WENBIT; not a new independent source of funding or participants.	In-trial total stroke; extended follow-up outcome is cardiovascular mortality only	Factorial HR0.76 (0.57-1.02), P=.07;181 cases differs from original-table sum 165	Contextual reanalysis, no additional independent trial weight; source-count discrepancy retained
Tardif et al. Effects of pyridoxal-5-prime-phosphate (MC-1) in patients undergoing high-risk coronary artery bypass surgery. J Thorac Cardiovasc Surg 2007;133:1604-1611.	Phase 2 randomized double-blind oral PLP-monohydrate placebo-controlled trial; abstract only	901 high-risk CABG patients; arm-specific stroke denominators unavailable in accessed abstract	Exact trial funding unconfirmed: accessed primary abstract has no funding statement and publisher full-text route failed. Manufacturer identity alone is not a verified funding declaration.	Prespecified death/nonfatal cerebral infarction/nonfatal MI composite at 30 days	250 mg/day composite relative reduction 14.0%, P=.3124; isolated stroke estimate unconfirmed	Separate oral vitamer/surgical stratum; positive MI-threshold analyses are not stroke efficacy
MEND-CABG II Writing Group. Efficacy and safety of pyridoxal 5-prime-phosphate (MC-1) in high-risk patients undergoing CABG. JAMA 2008;299:1777-1787.	Phase 3 double-blind placebo RCT of PLP; IV substitution allowed and used	3023 randomized:1519/1504; day 30 stroke denominators 1510/1486	Medicure International sponsored and participated in design/conduct/data management/interpretation/manuscript review; employee author and research relationships disclosed; academic statistical analysis.	Nonfatal stroke at 30 days, not the primary death/MI composite	24/1510 versus 25/1486, P=.83; no reported isolated-stroke HR/CI copied from composite	Indirect for strictly oral chronic prevention; manufacturer-funded, surgical setting
Saposnik et al. Homocysteine-lowering therapy and stroke risk, severity, and disability: additional findings from HOPE 2. Stroke 2009;40:1365-1372.	Stroke-outcome analysis of a randomized combined-vitamin trial	5522 adults;258 people with stroke over mean 5 years	Exact funding of this stroke reanalysis unconfirmed: primary abstract does not provide a funding declaration; no other trial funding copied.	Total stroke and nonfatal stroke; disability is a different outcome	Total-stroke HR0.75 (0.59-0.97); rates 0.88 vs 1.15/100 person-years	Relevant positive counterevidence for a combination, not isolated B6 efficacy
Toole et al. Lowering homocysteine in patients with ischemic stroke to prevent recurrent stroke, myocardial infarction, and death. JAMA 2004;291:565-575.	Double-blind high- versus low-dose three-vitamin RCT after ischemic stroke	3680 randomized;stroke analysis 1814 high-dose/1835 low-dose;31 had no follow-up	Specific grant attribution not confirmed in the funding information retrieved from the accessible article; not labeled independent solely because a university conducted it.	Recurrent ischemic stroke;2-year Kaplan-Meier risk	152/1814 vs 148/1835;KM9.2% vs 8.8%;adjusted HR1.1 (0.8-1.3)	Combination-dose strategy; neither placebo nor isolated B6 treatment
VITATOPS Trial Study Group. B vitamins in patients with recent TIA or stroke in VITATOPS. Lancet Neurol 2010;9:855-865.	Randomized double-blind combined-B-vitamin versus placebo trial; primary abstract	8164 randomized;4089 vitamins,4075 placebo;median 3.4 years	Abstract lists Australian NHMRC, UK MRC, Singapore biomedical/national medical councils, Australian Heart Foundation, Royal Perth Hospital foundation and Western Australian health department.	Primary composite of stroke,MI or vascular death	616 vs 678;RR0.91 (0.82-1.00), P=.05;not isolated-stroke effect	Secondary-prevention combination context; full subtype/isolated-stroke extraction unavailable
Hankey et al. Antiplatelet therapy and the effects of B vitamins in patients with previous stroke/TIA: a post-hoc subanalysis of VITATOPS. Lancet Neurol 2012.	Post-hoc baseline-antiplatelet subgroup analysis of VITATOPS	6609 baseline users and 1463 nonusers;8072 classified,not all 8164	Indexed UK MRC grant G0200583; full reanalysis funding declaration not accessible through the PMC route (captcha); parent-trial funding not substituted as complete reanalysis disclosure.	Major vascular composite by baseline antiplatelet strata	Treatment interactions are not randomized antiplatelet withdrawal and not isolated B6 efficacy	Same parent cohort, no independent replication weight; no medication-change advice
Dietary vitamin B6 intake and stroke are negatively associated in adults: A cross-sectional study from the NHANES. Heliyon 2024; e31125.	Cross-sectional dietary-recall study, not an intervention	24214 adults;921 reported previous stroke	Article states no specific funding and no declared competing interests.	Prevalent self-reported stroke, not prospective incidence	Highest vs lowest dietary quartile adjusted OR0.48 (0.35-0.66)	Association only; no supplemental B6 causal effect or NNT
Homocysteine, B vitamins, and cardiovascular disease: a Mendelian randomization study. BMC Medicine 2021.	Summary-data Mendelian randomization using 1 B6 instrument	Outcome-specific GWAS samples from consortia/UK Biobank/FinnGen;not one randomized treatment sample	EC Innovative Medicines Initiative (BigData@Heart), Wellcome Trust/Royal Society fellowship, Karolinska research foundation, Swedish Forte and Research Council, and Swedish Heart-Lung Foundation; authors state funders had no study or publication role and no competing interests. Outcome-consortium funding is separately acknowledged.	Ischemic stroke per 1-SD genetically predicted circulating B6	OR0.88 (0.81-0.97),P=.009;not significant after multiple-testing correction	Hypothesis-supporting association,not pill-dose or isolated oral efficacy evidence

Receipt — 15 References

Evidence access cutoff: 2026-09-17. Each citation states its actual access level (full-text transcription, abstract, index, or other) and remaining limitations. Bibliographic checking does not certify the study results or treatment efficacy.

Bonaa et al. Homocysteine lowering and cardiovascular events after acute myocardial infarction. NEJM 2006;354:1578-1588.