Outcome
    Moderate Evidence

    Vitamin D for Seasonal Mood Support

    Vitamin D helps if you are deficient, but it does not replace light therapy for seasonal depression.

    Overview

    Vitamin D helps if you are deficient, but it does not replace light therapy for seasonal depression.

    Verdict

    Insufficient evidence

    How It Works

    Vitamin D receptors in mood-regulating brain regions influence serotonergic and dopaminergic signalling.

    Dosing & Protocol

    Typical dose

    Recommended dose
    1000-2000 IU/day if deficient
    Expected timeframe
    8-12 weeks

    Protocol

    form
    Vitamin D3 (cholecalciferol) with a fat-containing meal
    duration
    Across the winter months in the seasonal trials
    co factor
    Evidence is insufficient. The seasonal hypothesis is intuitive - vitamin D falls in winter as sunlight declines, and seasonal affective disorder peaks then - and some small early trials, including work by Gloth, reported mood improvement with vitamin D. Larger and better-controlled evidence does not support it: VITAL-DEP randomised over 18,000 adults to 2,000 IU/day for a median 5 years with no effect on depression incidence or mood scores, and systematic reviews of vitamin D for seasonal affective disorder find the trials small, inconsistent and mostly at high risk of bias.
    titration
    Not applicable for this indication; 4,000 IU/day is the tolerable upper intake level
    starting dose
    Not established. Trials used 2,000 IU/day in VITAL-DEP and up to 100,000 IU as single doses in small seasonal studies

    Evidence

    What the studies say

    Trials of vitamin D for seasonal affective disorder are inconsistent, and large depression prevention trials such as VITAL-DEP found no benefit in replete populations.

    Light therapy and vitamin D for seasonal affective disorder: a systematic review

    Score: 7/10
    2019
    systematic_review

    Nussbaumer-Streit B, Forneris CA, Morgan LC +3 more

    Evidence for vitamin D in preventing winter depression was of very low quality

    View source

    Vitamin D status and serotonin metabolism: a randomized controlled trial of supplementation

    Score: 7/10
    2008
    rct
    n=441

    Jorde R, Sneve M, Figenschau Y +2 more

    Depression scale scores improved significantly in the vitamin D groups among participants with low baseline vitamin D

    View source

    Safety

    Caveats

    Light therapy has substantially stronger evidence for SAD.

    Less likely to help if

    Everyone as a mood treatment - the large trial was null and light therapy is better supported.

    Medical Disclaimer

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    Individual results may vary. The statements on this website have not been evaluated by the Food and Drug Administration. Products and information are not intended to diagnose, treat, cure, or prevent any disease.