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interventions / Vitamin D / cognition

Does Vitamin D help cognition? (Grade C evidence)

Explore current source-reported research for this exact question. These records are separate from the synthesis below; they do not update its grade or establish a recommendation.

Vitamin D shows a Grade C benefit for cognition: the recorded evidence, especially in older adults suggests a modest effect, low certainty. Dose range not applicable — observational association.

Exact question reviewed

Population
older adults
Intervention
Vitamin D · not applicable — observational association
Comparator
not reported
Outcome
cognition
Time horizon
not reported

Bottom line. Vitamin D shows a Grade C benefit for cognition: the recorded evidence, especially in older adults suggests a modest effect, low certainty. Dose range not applicable — observational association. [1 SR/meta]

Direction
benefit
Magnitude
Systematic review and meta-analysis: lower vitamin D levels are associated with poorer cognition and higher dementia risk. The association is mostly observational; supplementation trials have not established that raising vitamin D improves cognition.
Grade
C
Certainty
low
Clinical meaning
small but potentially useful
Who it applies to
older adults
Dose / form studied
not applicable — observational association
Safety
not assessed
The one limitation
Claim-specific limitation details are not available in this public record.

Reviewed not reported · Evidence last changed · Open evidence record (version 0)

Grade
C
what does the grade mean?
Certainty
low
what does certainty mean?

Grade C / low: hints of benefit in small trials; a well-run RCT could easily push this to B or to null.

Who it works for

Best-studied in older adults. Recorded studied dose: not applicable — observational association.

Evidence

StudyDesignRoleCite
Vitamin D, cognition, and dementia: a systematic review and meta-analysis.peer-reviewedsupportsPMID:23008220

Why this grade

Reasoning trace

The current record stores Grade C at low certainty and links 1 publishable source. A claim-specific domain-by-domain grading rationale is not available in this public record, so no reason for upgrading or downgrading is inferred here.

Audit and version

Claim ID
ec_b5-vitd-cognition
Claim version
not reported
Governance
legacy, not verified
Clinician review
Not yet reviewed by a licensed clinician
Last evidence search
not reported
Last editorial review
not verified

Public receipt · Machine-readable claim · Methodology

Dose & form

Studied intake: not applicable — observational association.

How it stacks up for cognition

Grade history

No grade changes yet. Initial grade assigned; re-reviewed on every 6 months (Grade C+). Methodology v1.

Re-review cadence: every 6 months (Grade C+) · methodology v1.

Frequently asked

How long does Vitamin D take to work for cognition?

This record does not report a studied onset time for Vitamin D and cognition. Do not assume a typical timeframe.

What dose was used in studies of Vitamin D for cognition?

The recorded studied dose for Vitamin D and cognition is not applicable — observational association. This is a source detail, not a dose recommendation.

Does Vitamin D work for cognition if I'm not deficient?

The recorded studied population is older adults. This field alone does not show whether deficiency or baseline status changes the effect.

Vitamin D or the next-best alternative for cognition?

See the compare block above for the head-to-head with the most-cited alternative. Grade + certainty differences matter more than any single trial.

Related

What this is — and is not

Evidence description
Systematic review and meta-analysis: lower vitamin D levels are associated with poorer cognition and higher dementia risk. The association is mostly observational; supplementation trials have not established that raising vitamin D improves cognition.
Substrate's interpretation
The current reviewed record assigns Grade C at low certainty. A domain-by-domain rationale is shown only when recorded.
Discuss with a clinician
If you're on medication or have a condition that changes the calculus, bring the interaction & population blocks above to your pharmacist or prescriber before deciding.
Individualized medical advice
Not provided here or on any Substrate surface (API, agent tool, embed) — see YMYL policy.

Cite this page

Citation is encouraged. The proposed reuse license is CC-BY-4.0; status: pending-governance-ratification.

Plain-text citation
Substrate. Does Vitamin D help cognition? (Grade C). https://evidencebased.info/interventions/vitamin-d/cognition. Updated 2026-07-16.
BibTeX
@misc{substrate_onsvitamindcognition,
  author = {Substrate editorial},
  title  = {Does Vitamin D help cognition?},
  year   = {2026},
  url    = {https://evidencebased.info/interventions/vitamin-d/cognition},
  note   = {Grade C, evidencebased.info}
}

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Current source-reported research

Membership uses admitted intervention and measured-outcome associations for this exact question. Different populations, preparations, comparators and timepoints remain separate. No pooling or update to the synthesis is asserted.