People started adding iodine to salt because in some parts of the world serious, chronic iodine deficiency was incredibly widespread, which was causing a range of health issues. But how was that solution arrived at?

Research:

• "Iodine." World of Chemistry, Gale, 2000. Gale In Context: Science, link.gale.com/apps/doc/CV2432500388/GPS?u=mlin_n_melpub&sid=bookmark-GPS&xid=42a73bea. Accessed 17 May 2024.
• "Iodine." World of Scientific Discovery, Gale, part of Cengage Group, 2007. Gale In Context: Science, link.gale.com/apps/doc/CV1648500324/GPS?u=mlin_n_melpub&sid=bookmark-GPS&xid=fabf4422. Accessed 17 May 2024.
• Bishai, David and Ritu Nalubola. “The History of Food Fortification in the United States: Its Relevance for Current Fortification Efforts in Developing Countries.” Economic Development and Cultural Change , Vol. 51, No. 1 (October 2002). https://www.jstor.org/stable/10.1086/345361
• Cameron, A.T. “Iodine Prophylaxis and Endemic Goitre.” Canadian Public Health Journal, Vol. 21, No. 11 (NOVEMBER, 1930). Via JSTOR. https://www.jstor.org/stable/41976052
• Cameron, A.T. “Iodine Prophylaxis and Endemic Goitre.” Canadian Public Health Journal, Vol. 21, No. 10 (OCTOBER, 1930). Via JSTOR. https://www.jstor.org/stable/41976030
• Cavanaugh, Ray. “How the arrival of iodized salt 100 years ago changed America.” Washington Post. 5/1/2024. https://www.washingtonpost.com/history/2024/05/01/iodized-salt-100-years-deficiency/
• Feyrer, James et al. “The Cognitive Effects of Micronutrient Deficiency.” Journal of the European Economic Association, April 2017. Via JSTOR. https://www.jstor.org/stable/10.2307/90023421
• Goodman, Johnah. “A National Evil: Jonah Goodman on the curse of the goitre in Switzerland.” London Review of Books. 11/30/2003. https://www.lrb.co.uk/the-paper/v45/n23/jonah-goodman/a-national-evil
• Kimball, O.P. “History of the Prevention of Endemic Goitre.” Bulletin of the World Health Organization. 1953.
• Kohn, Lawrence. “Goiter, Iodine and George W. Goler: The Rochester Experiment.” Bulletin of the History of Medicine, Vol. 49, No. 3 (FALL, 1975). Via JSTOR. https://www.jstor.org/stable/44450239
• Leung, Angela M et al. “History of U.S. iodine fortification and supplementation.” Nutrients vol. 4,11 1740-6. 13 Nov. 2012, doi:10.3390/nu4111740
• Markel, H. “’When it rains it pours’: endemic goiter, iodized salt, and David Murray Cowie, MD.” American journal of public health vol. 77,2 (1987): 219-29. doi:10.2105/ajph.77.2.219
• Markel, Howard. “A grain of salt.” The Milbank quarterly vol. 92,3 (2014): 407-12. doi:10.1111/1468-0009.12064
• McIntire, Tracey. “Gunpowder and Seaweed: The Story of Iodine.” National Museum of Civil War Medicine. 10/19/2022. https://www.civilwarmed.org/story-of-iodine/
• Newton, David E. "Iodine." Chemical Elements, edited by Kathleen J. Edgar, 2nd ed., UXL, 2010. Gale In Context: Science, link.gale.com/apps/doc/CV2640200041/GPS?u=mlin_n_melpub&sid=bookmark-GPS&xid=a54dec8e. Accessed 17 May 2024.
• Niazi, Asfandyar Khan et al. “Thyroidology over the ages.” Indian journal of endocrinology and metabolism vol. 15,Suppl 2 (2011): S121-6. doi:10.4103/2230-8210.83347
• Olsen, Robert. “Endemic Goiter in Switzerland: A Review of Recent Contributions to Its Etiology, Incidence, and Prevention.” Public Health Reports (1896-1970) , Jun. 9, 1933. Via JSTOR. https://www.jstor.org/stable/4580807
• Pearce, Elizabeth N. “Is Iodine Deficiency Reemerging in the United States?” AACE Clinical Case Reports. Volume 1, Issue 1, Winter 2015. https://www.sciencedirect.com/science/article/pii/S2376060520303680
• Stanbury, John, and John T. Dunn. "Iodine." Encyclopedia of Food and Culture, edited by Solomon H. Katz, vol. 2, Charles Scribner's Sons, 2003, pp. 281-283. Gale In Context: U.S. History, link.gale.com/apps/doc/CX3403400349/GPS?u=mlin_n_melpub&sid=bookmark-GPS&xid=12f688cc. Accessed 17 May 2024.
• Zimmermann, Michael B. and Maria Andersson, GLOBAL ENDOCRINOLOGY: Global perspectives in endocrinology: coverage of iodized salt programs and iodine status in 2020, European Journal of Endocrinology, Volume 185, Issue 1, Jul 2021, Pages R13–R21, https://doi.org/10.1530/EJE-21-0171
• Zoltan, Melanie Barton. "Salt." Food: In Context, edited by Brenda Wilmoth Lerner and K. Lee Lerner, vol. 2, Gale, 2011, pp. 699-702. In Context Series. Gale In Context: Global Issues, link.gale.com/apps/doc/CX1918600212/GPS?u=mlin_n_melpub&sid=bookmark-GPS&xid=21e3cd86. Accessed 17 May 2024.

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A lot of the stories that are told about popcorn in history – particularly in North America – are incorrect. Popcorn has been around for a very long time, though its rise to popularity as a snack has accelerated in recent years.

Research:

• “Ancient Popcorn Discovered in Peru.” Smithsonian. Jan, 20, 2012. https://www.si.edu/newsdesk/releases/ancient-popcorn-discovered-peru
• com Editors “Orville Redenbacher.” Biography.com. April 2, 2014. https://www.biography.com/business-leaders/orville-redenbacher
• Butler, Stephanie. “ A History of Popcorn.” History.com. Dec. 6, 2013. https://www.history.com/news/a-history-of-popcorn
• Delgado, Michelle. “The History of Popcorn: How One Grain Became a Staple Snack.” Serious Eats. May 7, 2023. https://www.seriouseats.com/popcorn-history-movie-theaters
• Dell’Amore, Christine. “Ancient Popcorn Found—Made 2,000 Years Earlier Than Thought in Peru.” National Geographic. Jan. 21, 2012. https://www.nationalgeographic.com/adventure/article/120119-national-popcorn-day-corn-peru-archaeology-food-science
• Geiling, Natasha. “Why do we eat popcorn at the movies?” Smithsonian. October 3, 2013. https://www.smithsonianmag.com/arts-culture/why-do-we-eat-popcorn-at-the-movies-475063/
• Goodspeed, T. H. “Plant Hunters in the Andes.” University of California Press. 1961. https://archive.org/details/planthuntersinan0000good
• Grobman, Alexander, et al. “Preceramic maize from Paredones and Huaca Prieta, Peru.” January 17, 2011. Proceedings of the National Academy of Sciences of the United States of America.
  https://doi.org/10.1073/pnas.1120270109
• Meyers, F.J. “IMPROVEMENT IN CORN-POPPERS.” Patent No. 171,032. Dec. 14, 1875. https://patents.google.com/patent/US171032A/en?q=(pop-corn)&q=(corn-popping)&sort=old
• “MICROWAVE KEY TO POPCORN WAR.” New York Times. June 22, 1987. https://www.nytimes.com/1987/06/22/business/microwave-key-to-popcorn-war.html
• Mola, Roger A. “Then and Now: Pass the Popcorn.” Smithsonian. March 2008. https://www.smithsonianmag.com/air-space-magazine/then-amp-now-pass-the-popcorn-13027292/
• “PopCorn: Ingrained in American’s Cultural History.” USDA National Agricultural Library. https://www.nal.usda.gov/exhibits/speccoll/exhibits/show/popcorn/early-history
• The Popcorn Board. “All About Popcorn.” https://www.popcorn.org/All-About-Popcorn/History-of-Popcorn
• “Popcorn Market Size, Share & Trends Analysis Report By Product (RTE, Microwave), By Distribution Channel (B2B, B2C), By Region (Asia Pacific, North America, Europe, MEA), And Segment Forecasts, 2022 – 2030.” Grandview Research. https://www.grandviewresearch.com/industry-analysis/popcorn-market-report
• Smith, Andrew F. “Popped Culture: A Social History of Popcorn in America.” University of South Carolina Press. 1999.
• “Sugar: The First and Last Food Rationed on the World War II Home Front.” National Park Service. https://www.nps.gov/articles/000/sugar-the-first-and-last-food-rationed-on-the-world-war-ii-home-front.htm

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This 2017 episode covers the work of Jules Cotard, the first psychiatrist to write about the cluster of symptoms that would come to be called Walking Corpse Syndrome. But his unfinished work was hotly debated among his colleagues.

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