Vitamin D is a naturally occurring nutrient that is synthesized by the body when the skin is exposed to sunlight. It was not "invented" by anyone, but its discovery and the role it plays in the body were the result of the work of several scientists over many years.
In 1922, a British biochemist named Sir Edward Mellanby discovered that rickets, a disease characterized by weak bones and deformities, could be cured by consuming cod liver oil, which is rich in vitamin D. This discovery led to the identification of vitamin D as a key nutrient in bone health.
Since then, many scientists have contributed to our understanding of vitamin D, including the chemist Adolf Windaus, who determined the chemical structure of vitamin D in the 1930s, and the physiologist Hector DeLuca, who helped develop methods for synthesizing and studying vitamin D in the 1960s and 1970s