There has been a lot of discussion about vitamin D circulating among natural health enthusiasts recently. As a certified functional medicine practitioner, vitamin D status is something that I monitor very closely. Vitamin D is actually a hormone, specifically a prohormone that the body converts into a steroid hormone. It’s synthesized in the skin from sun exposure and activated in the liver and kidneys. Lately, vitamin D has been a hotly discussed nutrient for its role in supporting the immune system. While vitamin D is a powerful modulator of the immune system, that’s far from its only role in human health. Functions of Vitamin D Vitamin D performs many functions throughout the body, many of them critical to core physiological processes. When we don’t have adequate vitamin D levels, it affects every aspect of our physiology because it’s intimately involved with cellular function and genetic expression. The hormone known as …