Yes, apparently the more we study vitamin D, the more amazing things we find out it does. It is apparently, rather important indeed. In this most recent study in the April American Journal of Clinical Nutrition, daily consumption of a vitamin D-fortified yogurt drink improved glycemic control in patients with type 2 diabetes in a randomized clinical trial.
Ninety diabetic subjects were assigned to consume plain yogurt drink, vitamin D–fortified yogurt drink, or vitamin D + calcium–fortified yogurt drink twice a day for 12 weeks. Fasting serum glucose, glycated hemoglobin, homeostasis model assessment of insulin resistance, serum lipid profile, and percentage fat mass were assessed.
In both the vitamin D and D+calcium groups, serum levels improved, waist circumference, and body mass index decreased significantly more than in the plain yogurt group.
"Our finding on the effect of the daily intake of a vitamin D–fortified yogurt drink (with or without added calcium) on body weight, fat mass, and waist circumference is noteworthy. Few previous studies have reported the effect of vitamin D supplementation on weight, and the results are contradictory. The weight-lowering effect of vitamin D could be indirectly due to its suppressing effect on parathyroid hormone, which is known to promote fat accumulation by increasing intracellular calcium concentrations," the study authors wrote. 
