A new study shows that most type-one diabetic children have low levels of vitamin D. Dr. Lori Laffel, senior author or the research, expressed surprise that only 24% of the children studied had adequate levels. The researchers then suggested that the children be supplemented with 400 IU daily.
What makes this research and its recommendations so interesting is that it is already established that supplementing 2,000 IU per day in children correlates to an 80% reduced risk of type-one diabetes. Why the surprise? Do these people read the research? Type-one diabetes is an autoimmune disease. In my book, I thoroughly cover the research showing that vitamin D is exceptionally effective in reducing autoimmune disorders. A study like this one is a case of "discovering" something that is already known and then expressing shock. Children need summer sunlight (without burning) and in winter they need sufficient vitamin D supplementation to maintain their summer levels. Believe me; 400 IU does not cut it.
Check with you doctor, and be sure your children have optimal levels of vitamin D, which will probably require at least 1,000 IU daily.
 Hypponen, E. et al. Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study. Lancet 2001;358:1500-03.