Vitamin D-3 is vital for many functions in our bodies, including the promotion of strong bones by assisting calcium metabolism. Vitamin D also influences a host of key biological functions vital to health and well-being. Vitamin D is called the “Sunshine Vitamin” because it is produced naturally by the body after exposure to 20 min – 1/2 hour of sunlight. Many people develop deficiencies due to lack of sun exposure, living in cold climates, and other reasons. Research continues to accumulate showing that vitamin D deficiency is widespread, and that this deficiency is linked to a wide range of illnesses. Vitamin D is most well known for its contribution to joint and bone health by helping the body absorb calcium. However, new research is showing that Vitamin D also plays a major role in immune function, and other metabolic processes important for the maintenance of health and well being. It is especially important to maintain adequate Vitamin D levels in children, as we age, and when we are under stress.