Description
Vitamin D is a key nutrient in many major biological functions. It maintains normal blood levels of calcium and phosphorus; promotes calcium absorption; helps to form strong bones and works in conjunction with other vitamins, minerals and hormones to promote bone mineralization. Research also suggests that vitamin D may help maintain a healthy immune system and help regulate cell growth and differentiation. Vitamin D is found in food and can also be made in the body after exposure to ultraviolet (UV) rays from the sun. Sun exposure is perhaps the most important source of vitamin D, providing most humans with their vitamin D requirement. However, many factors affect UV ray exposure and, consequently, vitamin D synthesis. It can also be difficult to obtain enough vitamin D from natural food sources.
