Vitamin D does not reduce risk of depression in adults, study finds

Vitamin D supplementation does not protect against depression in middle-age or older adulthood according to a new study by Massachusetts General Hospital (MGH) in Boston and published in the Journal of the American Medical Association.

The study included more than 18,000 men and women aged 50 years or older. Half the participants received vitamin D3 (cholecalciferol) supplementation for an average of five years, and the other half received a matching placebo for the same duration.

Vitamin D is sometimes called the "sunshine vitamin" because the skin can naturally create it when exposed to sunlight. Numerous prior studies showed that low blood levels of vitamin D, 25-hydroxy vitamin D, were associated with higher risk for depression in later life, but there have been few large-scale randomized trials necessary to determine causation. 

Among the 18,353 randomized participants, the researchers found the risk of depression or clinically relevant depressive symptoms was not significantly different between those receiving active vitamin D3 supplements and those on placebo, and there were no significant differences were seen between treatment groups in mood scores over time.

"It's not time to throw out your vitamin D yet though, at least not without your doctor's advice," said Olivia Okereke, MD, MS of MGH's psychiatry department. “[However], there was no significant benefit from the supplement for this purpose.”