Vitamin D was discovered in the early 20th century. In the early 1900s, a disease known as rickets was observed in children, characterized by softening and weakening of bones.
In the 1910s, American biochemist Dr. Elmer McCollum and his colleagues discovered that cod liver oil prevented and treated rickets. This led to the discovery of a fat-soluble substance in cod liver oil that was later named vitamin D.
Today, vitamin D is well understood for its role in calcium and phosphorus metabolism and the maintenance of healthy bones. It is synthesized in the skin when exposed to sunlight and can also be obtained from certain foods and supplements. It is widely used in the prevention and treatment of rickets and is considered an important component of a balanced diet. The discovery of vitamin D and its importance in human nutrition was a significant milestone in the field of nutrition science.