Many Eastern cultures, and perhaps some Western cultures, believed that a baby should be exposed to the sun so that the baby will develop strong bones. This belief is now backed by science. What actually happens is that the sun’s ultraviolet rays activate a certain substance in the skin. This substance is a precursor of vitamin D. Once vitamin D is formed, it helps the body absorb all the calcium it needs for forming and strengthening the bones, the teeth, and the cartilage. In an indirect way, calciferol or vitamin D can help an individual have strong teeth and bones.
However, not everyone people can use sunlight in forming the needed vitamin D. Some people live in places (such as the North Pole) where there is no sun for quite a long period of time. And some people live in places such as the Gobi desert, where the rays of the sun are dangerous, even in the early morning. Luckily, there are other sources of vitamin D, such as egg yolks or fishes. Milk, which is often described as a complete food, usually does not have vitamin D. But to make milk a true complete food, some producers fortify their milk and other dairy products with vitamin D.
A lack of vitamin D leads to imbalances in the physiological and biochemical make-up of the human body. The formation and mineralization of bones and teeth go awry. As a result, children suffer from rickets while adults develop osteomalacia.
To detect early the presence of rickets in kids, a parent must look for known symptoms such as lack of muscle tone, restlessness, or profuse sweating. The kids or baby will take a long period before he or she learns to sit, crawl or walk. Kids with rickets may have bowlegs or knock-knees. It was through the study of rickets that Edward Mellanby discovered vitamin D in 1922.
Osteomalacia is a condition in which the bones of adults are progressively losing the calcium mineral. Aside from this disease, an individual who lacks vitamin D may also suffer osteoporosis. This disease will make the bones of a person prone to fracture.
Since vitamin D is fat soluble, it is a vitamin that can be stored by the organism. It implies that vitamin D should not be ingested in large doses. When there is too much of it, vitamin D becomes toxic. It will make a person lose his appetite and his weight. He will experience nausea, vomiting, and general weakness. And he will suffer diarrhea.