[Vitamin-D deficiency].

Vitamin D helps the body absorb calcium. Along with calcium, it is vital for strong, healthy bones. We normally get vitamin D through exposure to sunlight, which triggers the skin to make this vitamin. Very few foods naturally contain vitamin D. Milk and a few other beverages and foods are “fortified” with added vitamin D in some countries, such as the United States and Canada. You can also get vitamin D in supplements.