In a new study which included 83,779 registered nurses followed for 20 years it was found that taking over 800 IU a day of vitamin D, combined with 1,200mg a day of calcium decreases the risk of developing type 2 diabetes by 33%. The researchers from Tufts-New England Medical Center state that the calcium can be from either supplementation or food, but the food source of vitamin D didn't offer much protection, it was vitamin D supplementation that protected from developing diabetes. Unfortunately, just recently a leading European Clinician, Professor Roger Bouillon from the University of Leuven reported at the recent European Congress of Endocrinology in Glasgow that over a billion people are deficient in vitamin D and they need to up their vitamin D intake.