A study from Oregon State University in the US suggests a relationship between low levels of vitamin D, and depression in otherwise healthy young women. Those with lower levels of vitamin D were more likely to have clinically significant symptoms over the course of a five-week study. The results were consistent even when researchers took into account other possible explanations, such as time of year, exercise and time spent outside.
A lot of past research has found no association between the two, but much of that research has been based on older adults or special medical populations.
This study focused on young women in the Pacific Northwest because they are at risk of both depression and vitamin D insufficiency. Researchers recruited 185 female college students, aged 18-25, to participate in the study at different times during the academic year. Vitamin D levels were measured from blood samples and participants completed a depression symptom survey over five weeks.
As expected, the women’s vitamin D levels depended on the time of year, with levels dropping during autumn, reaching their lowest in winter, and rising again in the spring. Depression did not show as a clear pattern, prompting the team to conclude that links between vitamin D deficiency and seasonal depression should be studied in larger groups of individuals. They say the study does not conclusively show that low vitamin D levels cause depression, and a clinical trial examining whether vitamin D supplements might help prevent or relieve depression is the logical next step to understanding the link between the two.
(Associations between vitamin D levels and depressive symptoms in healthy young adult women. Journal of Psychiatry Research, 30 May 2015.)