The relationship between vitamin K intake and depression Original paper

In this systematic review of 11 observational studies and 1 randomized controlled trial, higher vitamin K intakes were fairly consistently associated with a lower risk of depression or lower depression symptoms.

This Study Summary was published on June 5, 2025.

The study

The observational studies were either case-control or cross-sectional designs. The sample sizes ranged from 59 to 30,408 participants. Ten of the observational studies (91%) reported associations between a higher vitamin K intake and lower depression symptoms or a lower risk of depression.

In the randomized controlled trial, which included 84 women with polycystic ovary syndrome (PCOS), supplementation with 90 micrograms of vitamin K2 per day for 8 weeks reduced depression symptoms compared to a placebo; this effect was small and not clinically significant.[1][2]

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The results

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    This Study Summary was published on June 5, 2025.

    References

    1. ^K S Button, D Kounali, L Thomas, N J Wiles, T J Peters, N J Welton, A E Ades, G LewisMinimal clinically important difference on the Beck Depression Inventory--II according to the patient's perspectivePsychol Med.(2015 Nov)
    2. ^Hiroe T, Kojima M, Yamamoto I, Nojima S, Kinoshita Y, Hashimoto N, Watanabe N, Maeda T, Furukawa TAGradations of clinical severity and sensitivity to change assessed with the Beck Depression Inventory-II in Japanese patients with depression.Psychiatry Res.(2005-Jun-30)