The first scientific description of a vitamin D-deficiency, namely rickets, was provided in the 17th century by both Dr. Daniel Whistler (1645) and Professor Francis Glisson (1650).
The relationship between rickets and lack exposure to the sun was suspected for a long time.
In the past, children in cities or northern latitudes had soft bones. This was rickets, also known as ‘the English Disease’ and it became more common during the industrial revolution that began in England in the late 1700s.
Cod liver oil was first described as a medicinal agent for the treatment of chronic rheumatism in 1789.
Beginning in the 1820s, studies showed that administering doses of cod liver oil to afflicted children could cure rickets.
It was not until 1822 that a Polish physician noted that children living in the city of Warsaw were more likely to have rickets than children living in the countryside, which led him to prescribe sunlight as a cure for the disease.
The major breakthrough in understanding the causative factors of rickets was the development in the period 1910 - 1930 of nutrition as an experimental science and the appreciation of the existence of vitamins.
It was in 1919/20 that Sir Edward Mellanby, working with dogs raised exclusively indoors (in the absence of sunlight or ultraviolet light), devised a diet that allowed him to unequivocally establish that the bone disease, rickets was caused by a deficiency of a trace component present in the diet.
In 1923 Goldblatt and Soames clearly identified that when a precursor of vitamin D in the skin (7-dehydrocholestrol) was irradiated with sunlight or ultraviolet light, a substance equivalent to the fat-soluble vitamin was produced.
H. Steenbock of the University of Wisconsin demonstrated that when certain foods are irradiated with UV light they acquire antirachitic properties. It was later demonstrated that the responsible agent is found in the unsaponifiable fraction of the fat in the foods.
The substance activated by sunlight was called ‘provitamin D.’
The first analogue of the vitamins D were determined in the 1930s in the laboratory of Professor A. Windaus at the University of Gottingen in Germany.
With the chemical isolation and finally synthesis of the two parent or native D vitamins, vitamin D2 (egocalciferol) and vitamin D3 (cholecalciferol), an etiology therapy for rickets and osteomalacia was established.
Vitamin D2 which could be produced by ultraviolet irradiation of ergosterol was chemically characterized in 1932.
Vitamin D3 was not chemically characterized until 1936 when it was shown to result from the ultraviolet irradiation of 7-dehydrocholesterol. Discovery of Vitamin D
