Vitamin D is a fat-soluble vitamin that is important for maintaining healthy bones, teeth, and muscles. It helps the body absorb calcium, which is essential for building and maintaining strong bones. Vitamin D can be obtained through exposure to sunlight, some foods (such as fatty fish, egg yolks, and fortified milk or orange juice), and dietary supplements. Vitamin D deficiency can lead to a variety of health problems, including weakened bones (osteoporosis), increased risk of falls and fractures, and poor immune function. It is important to maintain adequate vitamin D levels through a balanced diet and/or supplementation, especially for individuals who are at risk of deficiency.