Vitamin D, known as the “sunshine vitamin” because it is only produced by the human body when exposed to sunlight, is essential for heath. We have known for years that vitamin D deficiency leads to a weakening of the bones, but more research is suggesting that vitamin D has links to cardiovascular health and depression as well.

During the last century, depression has increased, and vitamin D deficiency has increased as well. And although this correlation may not mean that a lack of vitamin D leads to depression, there is enough evidence mounting to support getting the 10-15 minutes of sunlight a day needed to product vitamin D, or to at least take it in supplement form.

A recent study looked at individuals who had experienced some type of heart disease or stroke, measures their vitamin D levels, and assessed them for depression. Interestingly, those with lower levels of vitamin D were more likely to be depressed than individuals with normal levels of vitamin D.

So as we approach winter and the sun gets dimmer and the days get shorter, remember that the seasonal depression many people experience may just be your body telling you it needs more vitamin D. Do yourself a favor a take a multivitamin and see if you feel better!

For more details on vitamin D and health, visit a story on vitamin D on CNN Health.