Depression has been linked to decreased levels of vitamin D in adults and the altered dietary intake of calcium and vitamin D has been reported to have implications for the development of depressive symptoms. Although, the relation between vitamin D and depression has been established, it is not yet clear whether the supplementation of vitamin D could affect the clinical manifestation of depression. Therefore, the aim of this study was to determine whether the supplementation of vitamin D could affect the development/course of depression.

A systematic literature search was performed for randomized control trials (RCTs) in which vitamin D was supplemented and depression was measured.

Six studies were identified as being eligible to be included in this review. The results regarding the supplementation of vitamin D and its effect on the course and manifestation of depression were conflicting. One study concluded that the supplementation of vitamin D3 had beneficial effect in depression and another study reported no improvement in the indices of mental well-being in the vitamin D supplemented group and rejected the hypothesis that an annual high dose of vitamin D3 could prevent depressive symptoms. The remainder four studies reported inconclusive results regarding vitamin D supplementation and the course of depression.

As current literature displayed contradictory results and no sound conclusion could be drawn regarding the supplementation of vitamin D and its effect on depression, there is a need of RCTs to determine whether the supplementation of vitamin D levels could affect depression.

The authors have not supplied their declaration of competing interest.