This description provides information on the importance of getting enough calcium and vitamin D in your diet. Calcium is essential for strong bones and teeth, while vitamin D helps your body absorb calcium and other minerals. Eating foods rich in calcium and vitamin D, such as dairy products, green leafy vegetables
From Wikipedia
Vitamin D is a group of structurally related, fat-soluble compounds responsible for increasing intestinal absorption of calcium and phosphate, along with numerous other biological functions. In humans, the most important compounds within this group are vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol).