Low vitamin D levels may increase depression risk

November 30, 2010

People with vitamin D deficiency may have an increased likelihood of suffering depressive episodes, a new US study suggests.

The study analyzed data from 7,970 US residents aged between 15 and 39 to assess the link between serum vitamin D levels and depression (1). The results showed that the likelihood of having depression in participants with vitamin D deficiency (vitamin D below 50 nmol/L) was significantly higher compared to those with vitamin D sufficiency (vitamin D above 75 nmol/L). Overall, about 50% of total participants had suboptimal serum vitamin D concentrations: 20% were vitamin D deficient and 30% were moderately vitamin D deficient (serum vitamin D 50-75 nmol/L). Higher prevalence of vitamin D deficiency was found in women, in non-Hispanic blacks, in overweight people, in people with lower income, in people living in urban areas and in people living in the south compared to their counterparts.

The researchers commented that, although a causal relation between depression and vitamin D deficiency still needs to be proven, from the public health perspective, the coexistence of vitamin D and depression in the US population at large is a concern. Furthermore, they found it important to identify persons who are at risk of vitamin D deficiency and/or depression and to intervene early because these two conditions have enormous negative consequences for long-term health.

In contrast to these findings, an earlier study found no significant association between serum concentrations of vitamin D and the presence of depression (2). However, a trend of decreasing depression and increased serum vitamin D concentrations was observed.

The mechanism through which vitamin D plays a role in mental health is not clearly
understood. It has been shown that vitamin D regulates gene expression of enzymes important for the synthesis of neurotransmitters which are involved in mood regulation and depression. Further studies are needed in deciphering the precise role of vitamin D in psychosomatic disorders.


  1. Ganji V. et al. Serum vitamin D concentrations are related to depression in young adult US population: the Third National Health and Nutrition Examination Survey. International Archives of Medicine. 2010; 3(29).
  2. Zhao G. et al. No associations between serum concentrations of 25-hydroxyvitamin D and parathyroid hormone and depression among US adults. Br J Nutr. 2010; 20:1–7.