Vitamin D Deficiency
There is a pandemic of vitamin D deficiency because we don't get the UVB rays from sunlight that are needed to make it ourselves. This leads to not only an increased risk of osteoporosis but also of type 2 diabetes, hypertension, several cancers, heart attacks, strokes, and seasonal affective disorder. Vitamin D replacement is necessary for most people. The immune effects of vitamin D are also reviewed.