An Irish study followed nearly 4,000 older adults for four years. The results showed that those with a vitamin D deficiency had a 75% higher risk of depression.
Dr. Eamon Laird, study co-author, said: "This study shows that vitamin D is associated with a health condition other than bone health. What is surprising is the large effect on depression even after accounting for other control variables. This is highly relevant for Ireland as our previous research has shown that one in eight older adults are deficient in the summer and one in four during the winter. Moreover, only around 8% of older Irish adults report taking a vitamin D supplement."
The correlation between vitamin D and depression is not exclusive to older adults. One study discovered that "vitamin D deficiency is linked to depressive symptoms" and more negative thoughts in young women. Results from the study indicated that "50% of young women have insufficient vitamin D levels."
Vitamin D is produced by the body through sunlight exposure. It can also be found in supplements and in high-level vitamin D foods such as oily fish and eggs.