Vitamin D and mood

Vitamin D is recognized as an important immune system support, helping regulate calcium and phosphate homeostasis, and to maintain bone integrity. In recent times vitamin D has been shown to function as a neurosteroid, playing a critical role in neural health and cognitive function.

Epidemiological research indicates that vitamin D deficiency is associated with a wide range of neuropsychiatric disorders and neurodegenerative disease, namely depression and anxiety. Observational studies show that low levels of vitamin D are seen in depressed people compared to controls.

The National Health and Nutrition Examination Survey, consisting of 7,970 US residents age 15–39 showed that people with serum vitamin D less than 50 nmol/L are at a significantly higher risk of depression than individuals who have serum levels of vitamin D greater or equal to more than 75 nmol/L.

Some randomised trials also suggest that supplementation during winter with vitamin D might help seasonal mood disorders. In addition, evidence from animal studies shows behavioural and anatomical changes in the hippocampus in animals with low vitamin D.

(The hippocampus is a complex brain structure which has a major role in learning and memory. It is affected by a variety of neurological and psychiatric disorders.)

Although there is a growing amount of research about the relationship between vitamin D deficiency and depression, it remains unclear whether vitamin D deficiency may be the result or the cause of the depression. Subjects with depression may be more likely to develop low vitamin D levels because of lower outdoor activity or reduced intake. Conversely, the identification of vitamin D receptors in many parts of the brain strengthens the plausibility of a relationship between vitamin D and depression.

In Australia, cholecalciferol (vitamin D3) is the most common vitamin D supplement. Once in the bloodstream cholecalciferol is converted into calciferol (25-hydroxyvitamin D, 25 (OH)D3) through the liver via hydroxylation, a complex chemical process. Calciferol is a highly bioavailable and potent form of vitamin D.