Vitamin D is a fat-soluble vitamin naturally found in some foods. It is also added to some fortified foods and can also be used as a dietary supplement. It is very important to our health. It can promote the formation of healthy bones in children, adults and the elderly. If there is not enough vitamin D, our bones will become thinner, brittle or weak; but if the content of vitamin D is sufficient, it can Prevent rickets in children and osteomalacia in adults. Studies have shown that the combined use of vitamin D and calcium can prevent osteoporosis in the elderly.