This is a great article reporting on the use of Vitamin D by Dr. L. Ray Matthews, an assistant professor of surgery at Morehouse School of Medicine and the Surgical Critical Care Director at Grady Memorial Hospital in Atlanta, Georgia, and how increasing dosage has helped his surgical patients recover faster and improve their health:

http://www.lef.org/magazine/mag2013/oct2013_Dr-L-Ray-Matthews-Unleashes-the-Power-of-Vitamin-D_01.htm