Doctors wanted to test the effects of vitamin D and calcium in diabetics who were deficient in vitamin D. In the study, 118 men and women with type 2 diabetes, who were taking standard blood sugar control medication and who were deficient in vitamin D took 50,000 IU of vitamin D per week with or without 1,000 mg of calcium per day, 1,000 mg of calcium per day alone, or a placebo. After eight weeks, serum insulin increased for placebo but declined in all calcium and vitamin D groups, with a far greater decrease, 38.7 percent, for those who took vitamin D with calcium. One month after  stopping the study, doctors measured long-term average blood sugar levels, and saw the greatest decrease in the vitamin D with calcium group. And in a surprising finding, LDL cholesterol declined 56.7 percent for those taking vitamin D with calcium.

Reference: Diabetologia; October, 2014, Vol. 57, No. 10, 2038-47.