Vitamin D is important to your health?

The August issue of The American Journal of Clinical Nutrition, has a supplement of articles, Vitamin D and Health in the 21st Century Update. ScienceDaily has some quotes from one of the main researchers:

… Norman identifies vitamin D’s potential for contributions to good health in the adaptive and innate immune systems, the secretion and regulation of insulin by the pancreas, the heart and blood pressure regulation, muscle strength and brain activity. In addition, access to adequate amounts of vitamin D is believed to be beneficial towards reducing the risk of cancer.

I think a focus on the immune system is important from an evolutionary perspective.