An insufficient vitamin D supply may increase depression risk

A new study from Japan reports that an insufficient vitamin D supply increases the risk for developing depressive symptoms among apparently healthy workers.

The observational study measured the blood vitamin D concentrations and depressive symptoms in 1786 workers (9% women), aged 19–69 years (1). The study results showed that 92% of the participants had a suboptimal vitamin D status (a 25(OH)D concentration below 30 micrograms/liter). The chance of developing depressive symptoms was significantly lower in workers with higher blood 25(OH)D concentrations, after adjustment for leisure-time physical activity and shift work – factors closely related to photo-initiated vitamin D production.

The researchers commented that accumulating evidence suggests a protective role of vitamin D against mood disorders, although epidemiologic studies are scarce in working populations. Low vitamin D levels have also been associated with depressive symptoms in earlier observational studies. However, the effect of vitamin D supplementation as an antidepressant remains uncertain (2). Vitamin D supplementation may be effective for reducing depressive symptoms in patients with clinically significant depression.

1. Mizoue T. et al. Low Serum 25-Hydroxyvitamin D Concentrations Are Associated with Increased Likelihood of Having Depressive Symptoms among Japanese Workers. J. Nutr. Published online December 2014.
2. Shaffer J. A. et al. Vitamin D supplementation for depressive symptoms: a systematic review and meta-analysis of randomized controlled trials. Psychosom Med. 2014; 76(3):190-196.