Vitamin D and depression
Vitamin D has been proposed to be involved in various functions of the central nervous system and vitamin D deficiency has been associated with a number of psychiatric conditions. The present short review provides an overview of the potential role of vitamin D in the etiology and therapy of depression. Recent meta-analyses have indicated an inverse association between 25-hydroxyvitamin D (25(OH)D) levels and the risk of depression, i.e. low vitamin D concentrations are associated with depression while higher serum 25(OH)D levels appear to protect against depression. Randomized controlled trials are needed in order to determine whether this association is causal and to assess the effects of vitamin D administration in the prevention and treatment of depression. Due to methodological problems of the available studies there is at present no clear evidence of an association between vitamin D status and depression.
Vitamin D comprises a group of fat-soluble secosteroids, the two main forms in humans are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol) (1). Both vitamin D2 and vitamin D3 can be provided by the diet (vitamin D2 mainly in plants and yeast, vitamin D3 primarily in fatty fish). In addition, cholecalciferol can be derived from sun exposure since it is converted in the skin of mammals from 7-dehydrocholesterol under the influence of ultraviolet B radiation (1). Dietary intake and synthesis from exposure to sunlight generally suffice in order to maintain adequate serum concentrations. Vitamins D2 and D3 are metabolized in the liver and a person’s vitamin D status is commonly assessed by measuring serum levels of their metabolites 25-hydroxyvitamin D2 (25(OH)D2) and 25-hydroxyvitamin D3 (25(OH)D3) (2).
Vitamin D plays an important role in calcium and phosphate homeostasis and its deficiency has been attributed to a large variety of diseases including osteoporosis and various cancers (1). Vitamin D deficiency has also been associated with psychiatric conditions (3). An association of vitamin deficiency with mental disorders with a de ...