The “Sunshine Vitamin” has an enormous impact on our overall health. Vitamin D is a prohormone (a vitamin that converts into a hormone) that travels through your blood and tissues like a Wi-Fi signal. Once inside your cells, it enters the nucleus, turning on over 900 genes. Some affect bone metabolism, others suppress tumor formation, others reduce inflammation, and others are essential for creating and maintaining brain synapses. With our modern lifestyle, this vitamin is as essential as it is neglected: an estimated 1 billion people worldwide are deficient.