92 Vitamin A History

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𝐒𝐮𝐛𝐬𝐜𝐫𝐢𝐛𝐞 𝗙𝐨𝐫 𝗠𝐨𝐫𝐞 𝗜𝐧𝐟𝐨𝐫𝐦𝐚𝐭𝐢𝐨𝐧 𝐨𝐧 𝗛𝐞𝐚𝐥𝐭𝐡 👩‍⚕‍ 𝐚𝐧𝐝 𝗠𝐞𝐝𝐢𝐜𝐢𝐧𝐞💉🩺💊 • 𝐘𝐨𝐮𝐭𝐮𝐛𝐞 : / @draishwaryakelkar • 📌𝗙𝗮𝗰𝗲𝗯𝗼𝗼𝗸 : / draishwaryakelkar • 📌𝗧𝘄𝗶𝘁𝘁𝗲𝗿: / aishwayadr • 📌𝗜𝗻𝘀𝘁𝗮𝗴𝗿𝗮𝗺 : / clinical.learning • Vitamin A is essential for normal growth, reproduction, immunity, and vision. The characterization of vitamin A spanned a period of about 130 years. During this long, incremental process, there is no single event that can be called the 'discovery' of vitamin A. The physiologist François Magendie conducted nutritional deprivation experiments with dogs in 1816 that resulted in corneal ulcers and high mortality - a finding similar to the common clinical situation in poorly fed, abandoned infants in Paris. In the 1880s, Nicolai Lunin showed that there was an unknown substance in milk that was essential for nutrition. • Carl Socin suggested that an unknown substance for growth in egg yolk was fat soluble. Frederick Gowland Hopkins proposed in 1906 that there were 'unsuspected dietetic factors' that were necessary for life. In 1911, Wilhelm Stepp demonstrated that this essential substance in milk was fat soluble. The following year, Hopkins showed that there were 'accessory factors' present in 'astonishingly small amounts' in milk that supported life. Contrary to the dogma that all fats had similar nutritional value, in 1913, Elmer McCollum and Marguerite Davis at Wisconsin and Thomas Osborne and Lafayette Mendel at Yale showed butter and egg yolk were not equivalent to lard and olive oil in supporting the growth and survival of rats. The growth-supporting 'accessory factor' became known as 'fat-soluble A' in 1918 and then 'vitamin A' in 1920. Paul Karrer described the chemical structure of vitamin A in 1932. • • #vitaminA #vitamins #biochmeistry #chemistry #mbbs #medico #medicalstudent

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