I. General information:1. The History of the Nutrient: Since ancient times, vitamin D has been the predominant cause of bone deficiencies.1 However, it was not until the 17th century that Dr. Daniel Whistler and Professor Francis Glisson made the first scientific description of a vitamin D deficiency.2 In the mid-17th century, an increasing number of children were diagnosed with a bone disease called rickets.2 The cause of rickets was determined to be associated with lack of sunlight. German researcher Kurt Huldschinsky came to the conclusion that when infants were exposed to ultraviolet rays, they were cured of rickets2. He stated that a substance found in the skin was the potential source of the remedy.2 In 1922, American scientist Elmer McCollum proved that when cod liver oil was heated; the beneficial effects of the vitamin A in the oil were reduced.2 However, the oil remained effective in curing rickets, leading McCollum to believe that a different nutrient than vitamin A was present in the oil. 'oil. As a result, he named this nutrient vitamin D, which became the fourth vitamin to be discovered and named.2 Additionally, shortly after 1918, vitamin D was also discovered through an accidental experiment involving a group of scientists healing dogs suffering from rickets by giving them cod liver oil.12. The chemical characteristics and qualities of the nutrient• Vitamin D2 (cholecalciferol) comes from yeast and the plant sterol, ergosterol.3• Vitamin D3 (ergocalciferol) comes from 7-dehydrocholesterol, a precursor of cholesterol when it is synthesized in the skin.3• Vitamin D is derived from a steroid; the structure retains its numbering from the parent compound cholesterol.3• Name o...... middle of paper ......casein-free diet was 19.9 ng⁄mL, for participants not following a casein-free diet it was 19.6ng⁄mL, and for controls it was 17ng⁄mL. There were no differences in 25(OH)D measurements in all groups. Approximately sixty-one percent, or fifty-four children, had concentrations below 20 ng⁄mL. This is the minimum concentration recommended by the American Academy of Pediatrics to ensure good bone health. These children could be at risk for problems related to vitamin D deficiency. This includes concerns about bone health and calcium and phosphorus metabolism. Children with autism spectrum disorder are limited in the activities they can do and are generally not exposed to much sunlight, putting them at higher risk. Understanding the needs and taking preventative measures for children with autism will help reduce the risk of health problems as adults...