We have recently written about the link between vitamin D and depression.  While several studies have indicated that low vitamin D levels may be associated with depression, we lack randomized, controlled trials assessing the benefits of vitamin D supplements for the treatment (or prevention) of depression.  A recent report from the Women’s Health Initiative Calcium and Vitamin D Trial included 36,282 women (50 to 80 years of age) who were randomized to receive 400 IU vitamin D (with 1000 mg calcium) or to placebo.

After 2 years, supplementation with vitamin D had no effect on risk for depressive symptoms.

This is a well-done study and certainly the largest to assess the effects of vitamin D on depression.  However, Dr. Peter Roy-Byrne notes in his commentary, this study did not answer the question of whether depressed patients with low vitamin D levels might improve with vitamin D supplements.

Bertone-Johnson ER et al. Vitamin D supplementation and depression in the Women’s Health Initiative Calcium and Vitamin D Trial. Am J Epidemiol 2012; 176:1.

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