Vitamin D: This fat-soluble vitamin is also known as the "sunshine vitamin." It helps maintain strong bones and teeth by increasing the absorption of calcium and phosphorus. Vitamin D is actually acquired from the sun or through the diet. This vitamin works as a partner with “Vitamin A.” Vitamin D is needed for healthy bones and teeth. Children need it for proper growth. It also works with Vitamin C. The body's nervous system, heart and blood depend on the "sunshine vitamin".

Rickets and osteomalacia are classic vitamin D deficiency diseases. In children, vitamin D deficiency causes rickets, which results in skeletal deformities. In adults, vitamin D deficiency can lead to osteomalacia, which results in muscular weakness in addition to weak bones. Populations who may be at a high risk for vitamin D deficiencies include the elderly, obese individuals, exclusively breastfed infants, and those who have limited sun exposure. Also, individuals who have fat malabsorption syndromes (e.g., cystic fibrosis) or inflammatory bowel disease (e.g., Crohn's disease) are at risk.