INS and vitamin D deficiency: Some animal experiments to identify the impact of maternal vitamin D deficiency on glucose metabolism in normal and high-fat diets observed glucose homeostasis (fasting glucose, fasting insulin, HOMA-IR and insulin tolerance tests) of adult offspring mice with no modifications in the normal diet; however, the high-fat diet combined with maternal vitamin D deficiency could aggravate the disruption of glucose homeostasis in the male offspring (20, 35).