Vitamin D is essential for several reasons, including maintaining healthy bones and teeth. It may also protect against a range of diseases and conditions, such as type 1 diabetes. Despite its name, vitamin D is not a vitamin, but a prohormone, or precursor of a hormone. Vitamins are nutrients that the body cannot create, and so a person must consume them in the diet. However, the body can produce vitamin D. Vitamin D is known as the "sunshine" vitamin. It is an essential fat-soluble nutrient. It helps keep bones healthy and strong, helps cell growth, and benefits immune function.
Studies have shown a link between vitamin D deficiency and depression. Researchers noticed that in a study, participants with depression also had low vitamin D levels. The same analysis found that, statistically, people with low vitamin D were at a much greater risk of depression.
The researchers believe that because vitamin D is important to healthy brain function, insufficient nutrient levels may play a role in depression and other mental illnesses. An earlier study identified vitamin D receptors in the same areas of the brain associated with depression.