WEBVTT - Iodized Salt 0:00:01.320 --> 0:00:04.280 Welcome to Stuff You Missed in History Class, a production 0:00:04.400 --> 0:00:14.520 of iHeartRadio. Hello, and welcome to the podcast. I'm Tracy V. 0:00:14.640 --> 0:00:16.080 Wilson and I'm Holly Frye. 0:00:16.960 --> 0:00:19.720 Back at the beginning of May, I read an article 0:00:19.760 --> 0:00:23.560 in the Washington Post called how the arrival of iodized 0:00:23.680 --> 0:00:27.560 salt one hundred years ago changed America. And I was 0:00:27.600 --> 0:00:30.960 immediately fascinated by this whole thing, And I also wanted 0:00:31.000 --> 0:00:34.720 to learn more than a thousand word newspaper article could 0:00:34.720 --> 0:00:37.920 tell me. I already knew, and I think maybe a 0:00:37.920 --> 0:00:41.000 lot of folks already knew from something like elementary school 0:00:41.040 --> 0:00:45.479 health class that iodine is added into table salt because 0:00:45.520 --> 0:00:50.120 our bodies need that iodine for thyroid reasons. And I 0:00:50.200 --> 0:00:53.880 also knew there are various people who, for whatever reason, 0:00:54.040 --> 0:00:57.240 don't like iodized salt or don't want to use it, 0:00:57.320 --> 0:00:59.320 and that was sort of the sum of my knowledge 0:00:59.320 --> 0:01:03.520 about the iodide salt. And so reading this Washington Post article, 0:01:03.600 --> 0:01:07.319 I didn't really grasp that adding the iodine to the 0:01:07.360 --> 0:01:10.240 salt was not just like a nutritional nice to have. 0:01:10.920 --> 0:01:14.200 They were not like well meaning public health people kind 0:01:14.240 --> 0:01:16.320 of like, wouldn't it be great if everybody just had 0:01:16.440 --> 0:01:20.440 enough iodine, just because it was to try to deal 0:01:20.480 --> 0:01:23.760 with a problem that in some parts of the world 0:01:23.920 --> 0:01:29.400 was really serious with chronic iodine deficiency. It was incredibly 0:01:29.480 --> 0:01:32.240 widespread in some places, and that was causing a range 0:01:32.400 --> 0:01:36.360 of actual health issues, not just wouldn't it be great 0:01:36.400 --> 0:01:37.600 if we all got enough iodine. 0:01:38.280 --> 0:01:41.880 So a complete history of salt would be its own episode, 0:01:41.959 --> 0:01:44.160 or perhaps even more than one. You could even have 0:01:44.240 --> 0:01:47.040 the story of salt as an entire podcast. I imagine. 0:01:47.680 --> 0:01:51.920 Of course, edible salt or sodium chloride makes food more flavorful, 0:01:52.120 --> 0:01:55.360 and it's an electrolyte that our bodies need to function correctly. 0:01:56.160 --> 0:02:00.520 Salt can also be used to preserve food through salting, curing, brining, 0:02:00.640 --> 0:02:04.279 or pickling, and there are lots of non dietary uses 0:02:04.320 --> 0:02:07.760 for it as well. So for those and other reasons, 0:02:07.800 --> 0:02:10.959 people have wanted and needed salt, going all the way 0:02:11.000 --> 0:02:15.440 back to our earliest beginnings, cultures all around the world 0:02:15.520 --> 0:02:20.600 have boiled or evaporated salt from water, including seawater and 0:02:20.720 --> 0:02:25.320 water from salt lakes or mineral springs. Animals besides us, 0:02:25.400 --> 0:02:28.320 need salt to often they get it from licking at 0:02:28.440 --> 0:02:32.160 salt deposits. So people who are living farther inland could 0:02:32.200 --> 0:02:35.160 sometimes find sources of salt by just watching what the 0:02:35.200 --> 0:02:39.959 animals were doing, even if salt had no other uses. 0:02:40.240 --> 0:02:43.760 Its importance in flavoring and preserving food has made it 0:02:43.840 --> 0:02:47.400 highly sought after all over the world for basically all 0:02:47.480 --> 0:02:51.360 of history. Some of the world's earliest trade networks were, 0:02:51.440 --> 0:02:55.080 of course, salt roads, and many of the earliest governments, 0:02:55.160 --> 0:02:59.440 established thousands of years ago, regulated the salt trade and 0:02:59.560 --> 0:03:05.800 establish salt stockpiles. Iodine is not nearly as abundant assault, 0:03:05.880 --> 0:03:10.480 but it is similarly critical. People and all other vertebrate 0:03:10.560 --> 0:03:15.040 animals need iodine for our bodies to function properly. Specifically, 0:03:15.240 --> 0:03:19.000 the body uses iodine to make thyroid hormones, and thyroid 0:03:19.040 --> 0:03:23.600 hormones regulate a number of body functions, including growth and metabolism, 0:03:23.919 --> 0:03:27.800 affecting virtually every cell in the body. The iodine we 0:03:27.919 --> 0:03:30.920 consume moves from the digestive system to the blood and 0:03:31.000 --> 0:03:34.840 from there to the thyroid gland, which produces those hormones. 0:03:35.680 --> 0:03:39.000 People only need a little bit of iodine. In the 0:03:39.160 --> 0:03:42.680 United States, the recommended daily allowance is only one hundred 0:03:42.720 --> 0:03:46.720 and fifty micrograms a day for adults. It's roughly half 0:03:46.800 --> 0:03:51.320 that For babies and children, the recommended daily allowance increases 0:03:51.360 --> 0:03:54.840 to two hundred and twenty micrograms during pregnancy and two 0:03:54.960 --> 0:03:59.119 hundred and ninety micrograms while lactating. But whether people can 0:03:59.160 --> 0:04:03.240 get that much eye iodine without access to fortified foods 0:04:03.360 --> 0:04:08.040 like iodized salt varies widely depending on where they live. 0:04:08.800 --> 0:04:12.640 There's iodine in seawater, and it's in the Earth's crust, 0:04:12.800 --> 0:04:15.840 but exactly how much iodine there is in a particular 0:04:15.880 --> 0:04:19.039 location depends on things like how close it is to 0:04:19.120 --> 0:04:22.880 the sea and geological changes that have taken place over 0:04:23.040 --> 0:04:24.800 thousands and thousands of years. 0:04:25.600 --> 0:04:28.960 The presence of iodine in seawater means that various types 0:04:29.000 --> 0:04:32.880 of seaweed and marine animals are also high in iodine, 0:04:33.240 --> 0:04:36.440 so people living in an island nation like Japan, where 0:04:36.480 --> 0:04:39.560 the traditional diet includes a lot of seafood and seaweed 0:04:40.080 --> 0:04:42.640 may be able to get enough iodine through their regular 0:04:42.720 --> 0:04:45.080 diet without some kind of supplementation. 0:04:46.560 --> 0:04:51.160 Generally speaking, things get trickier farther inland. How much iodine 0:04:51.200 --> 0:04:54.599 is available to people and animals depends on how much 0:04:54.600 --> 0:04:57.920 of it is present in the soil, so, for example, 0:04:58.080 --> 0:05:01.040 cows grazing on a pasture near the sea, where the 0:05:01.040 --> 0:05:04.279 iodine in the soil is replenished by the spray blowing 0:05:04.360 --> 0:05:07.080 in from the ocean, they might get enough iodine, and 0:05:07.120 --> 0:05:09.400 that means there would also be iodine in their milk. 0:05:10.000 --> 0:05:14.120 But high altitudes places where there are recurring floods or 0:05:14.160 --> 0:05:18.880 cycles of glaciers melting and refreezing, those places typically have 0:05:19.200 --> 0:05:22.400 very little iodine in the soil, so without some kind 0:05:22.440 --> 0:05:26.240 of supplementation, people and animals living there cannot get enough 0:05:26.279 --> 0:05:27.600 iodine in their diets. 0:05:28.120 --> 0:05:30.919 This isn't only a problem for humans who rely on 0:05:30.960 --> 0:05:35.719 these animals for food. Iodine deficiency in livestock is connected 0:05:35.720 --> 0:05:38.640 to things like still births, the deaths of young, and 0:05:38.760 --> 0:05:42.559 lower production of eggs and milk. As a side note, 0:05:42.640 --> 0:05:45.320 in today's world, some of the iodine and milk doesn't 0:05:45.360 --> 0:05:48.280 actually come from what the cows are eating. It's from 0:05:48.320 --> 0:05:52.159 the use of iodine as an antiseptic or sterilizer, both 0:05:52.200 --> 0:05:55.080 on the cow's utters and on equipment that's used in 0:05:55.080 --> 0:05:56.040 the dairy industry. 0:05:56.800 --> 0:05:59.279 There are also some things that can interfere with the 0:05:59.279 --> 0:06:03.920 bodies of bil to absorb iodine, including compounds found in 0:06:04.000 --> 0:06:08.800 cassava and millet, and some chemical pollutants. So a person 0:06:09.080 --> 0:06:12.240 living in an area where the soil is low in iodine, 0:06:12.600 --> 0:06:15.560 or whose diet includes a lot of those foods somebody 0:06:15.560 --> 0:06:18.599 who's exposed to these kinds of pollutants. These people could 0:06:18.640 --> 0:06:22.840 have even more difficulty getting enough iodine In people. 0:06:23.000 --> 0:06:26.160 Iodine deficiency can lead to a number of health issues. 0:06:26.720 --> 0:06:29.280 As we said earlier, the body needs iodine to make 0:06:29.320 --> 0:06:33.320 thyroid hormones. If the thyroid gland isn't getting enough iodine 0:06:33.320 --> 0:06:36.440 to do this, it enlarges as it tries to filter 0:06:36.600 --> 0:06:40.760 more iodine from the blood. This enlarged thyroid gland is 0:06:40.800 --> 0:06:43.520 called a goiter, and a goiter can put pressure on 0:06:43.560 --> 0:06:45.840 the blood vessels in the neck and on the trachea. 0:06:46.680 --> 0:06:50.039 There are other things that can cause goiter, including autoimmune 0:06:50.080 --> 0:06:54.920 disorders like graves disease, thyroid nodules, and cancers, but iodine 0:06:54.920 --> 0:06:59.200 deficiency is the most common cause of goiter worldwide, and yes, 0:06:59.440 --> 0:07:02.520 non human and animals can also develop goiter. 0:07:02.960 --> 0:07:04.320 Without enough iodine. 0:07:04.360 --> 0:07:07.599 The body also can't make enough thyroid hormone that leads 0:07:07.640 --> 0:07:14.720 to hypothyroidism. Symptoms and effects of hypothyroidism include things like fatigue, listlessness, 0:07:14.800 --> 0:07:20.600 difficulty concentrating, dry skin, feeling cold all the time, depression, 0:07:21.080 --> 0:07:26.480 irregular menstrual periods, among other things. Iodine and thyroid hormones 0:07:26.520 --> 0:07:30.080 also play an important role in brain development in utero. 0:07:30.200 --> 0:07:33.920 Iodine deficiency during pregnancy can lead to babies being born 0:07:33.960 --> 0:07:38.080 with congenital iodine deficiency syndrome, which a startling number of 0:07:38.120 --> 0:07:41.000 sources are still right now in the year twenty twenty 0:07:41.080 --> 0:07:45.160 four while we record this describing using the word cretinism, 0:07:45.400 --> 0:07:49.360 even though at this point that term has deeply insulting connotations. 0:07:50.160 --> 0:07:55.160 Congenital iodine deficiency syndrome can lead to developmental disabilities, deafness 0:07:55.160 --> 0:08:00.120 and inability to speak, and muscular skeletal issues. Treatment with 0:08:00.160 --> 0:08:04.320 iodine can resolve many of the issues associated with hypothyroidism, 0:08:04.640 --> 0:08:08.280 including the physical changes in babies born with congenital iodine 0:08:08.320 --> 0:08:12.360 deficiency syndrome, but not the damage to the brain that 0:08:12.440 --> 0:08:17.840 takes place during fetal development. Iodine wasn't discovered until the 0:08:17.920 --> 0:08:21.200 nineteenth century, but people in various parts of the world 0:08:21.280 --> 0:08:24.960 connected foods that are high in iodine with the prevention 0:08:25.080 --> 0:08:28.960 and treatment of goiter thousands of years ago. Documents from 0:08:29.040 --> 0:08:32.600 China dating back to about thirty six hundred BCE describe 0:08:32.640 --> 0:08:37.160 a reduction in goiter after eating seaweed or burned sea sponge. 0:08:37.760 --> 0:08:40.840 Seaweed and sea sponge continued to show up in medical 0:08:40.880 --> 0:08:45.959 texts in Asia, Europe, and Northern Africa afterward. Ierveateic texts 0:08:45.960 --> 0:08:49.360 from the Indian subcontinent dating back to about fourteen hundred 0:08:49.360 --> 0:08:56.000 BCE also include descriptions of hyperthyroidism and hypothyroidism, with treatments 0:08:56.000 --> 0:09:01.000 for hypothyroidism including things like milk, various grains, and bladder rack, 0:09:01.120 --> 0:09:05.720 which is a type of seaweed. Overall, earlier medical writers 0:09:05.800 --> 0:09:09.880 didn't know exactly what caused goiter. For example, those same 0:09:10.040 --> 0:09:14.480 Aervedic texts conclude that goiter was caused by edema, and 0:09:14.600 --> 0:09:18.000 various physicians throughout history have blamed goiter on a range 0:09:18.000 --> 0:09:22.080 of illnesses, poisons, and even tumors. But there are also 0:09:22.120 --> 0:09:25.480 written records of people making a connection between goiter and 0:09:25.520 --> 0:09:31.120 the symptoms of hypothyroidism like fatigue and difficulty concentrating. In 0:09:31.160 --> 0:09:35.120 the tenth century, Arab historian and geographer Al mas Udi 0:09:35.320 --> 0:09:40.440 described Europeans as having quote large bodies, dull understanding, and 0:09:40.520 --> 0:09:44.160 heavy tongues, which is often interpreted as a reference to 0:09:44.240 --> 0:09:49.679 how many people had hypothyroidism. In the sixteenth century. Paracelsus 0:09:49.720 --> 0:09:53.160 also made a connection between parents with goiter and children 0:09:53.200 --> 0:09:57.600 born with developmental delays and disabilities. People started to get 0:09:57.600 --> 0:10:02.079 a clearer understanding of the relationship but between goiter, thyroid hormone, 0:10:02.120 --> 0:10:05.640 and iodine after iodine was discovered in the nineteenth century. 0:10:06.120 --> 0:10:14.400 We'll have more on that after a sponsor break. In 0:10:14.720 --> 0:10:19.600 eighteen eleven, French pharmacist and chemist Bernon Courtois was working 0:10:19.600 --> 0:10:24.360 with seaweed at his father's saltpeter factory. This process involved 0:10:24.400 --> 0:10:27.319 burning the seaweed to produce soda ash and then adding 0:10:27.360 --> 0:10:31.000 sulfuric acid to it. One day, by accident, he added 0:10:31.040 --> 0:10:35.320 too much sulfuric acid. In the words of Humphrey Davy, 0:10:35.440 --> 0:10:40.960 this produced quote a beautiful violet vapor. Courtois was not 0:10:41.000 --> 0:10:43.600 sure what this vapor was, but he called it by 0:10:43.640 --> 0:10:48.000 the Greek word iodes, meaning violet. He didn't have time 0:10:48.120 --> 0:10:50.960 to really experiment with this, so he gave a sample 0:10:51.080 --> 0:10:52.960 to Joseph Luis Gaerusac. 0:10:53.520 --> 0:10:54.520 We talked about. 0:10:54.280 --> 0:10:57.319 This in our recent episode on Humphrey Davy, Davy and 0:10:57.520 --> 0:11:02.200 Gaelusac each described iodine as an element in eighteen thirteen. 0:11:02.640 --> 0:11:05.199 They made those descriptions about a week apart, and then 0:11:05.200 --> 0:11:07.400 they had an argument about who should get the credit 0:11:07.440 --> 0:11:07.720 for it. 0:11:08.440 --> 0:11:12.160 Like so many other newly discovered substances, once it had 0:11:12.160 --> 0:11:16.280 been identified and isolated, iodine made its way into medicines 0:11:16.320 --> 0:11:20.000 meant to treat all kinds of things. Of course, it 0:11:20.040 --> 0:11:22.520 didn't have an effect on most of them, and this 0:11:22.679 --> 0:11:26.080 experimental iodine treatment also carried the risk of what came 0:11:26.120 --> 0:11:30.400 to be known as the yod Basidou phenomenon. Yaod is 0:11:30.440 --> 0:11:34.040 the German word for iodine, and Carl Adolf von Basidu 0:11:34.200 --> 0:11:37.080 was the nineteenth century German doctor who worked with it. 0:11:37.760 --> 0:11:42.679 He was reportedly the first person to describe thyrotoxicosis, which 0:11:42.720 --> 0:11:45.800 occurs when there is too much thyroid hormone circulating in 0:11:45.840 --> 0:11:50.440 a person's body. The yod bazidoo effect is thyrotoxicosis in 0:11:50.480 --> 0:11:53.400 response to treatment with iodine. 0:11:53.559 --> 0:11:58.520 As a note, sometimes the terms thyrotoxicosis and hyperthyroidism are 0:11:58.600 --> 0:12:02.040 used interchangeably, but they're there are some slight nuances between 0:12:02.080 --> 0:12:05.080 these two terms. Those nuances are a little outside the 0:12:05.120 --> 0:12:09.680 scope of a generalist history podcast. Both of them however, 0:12:09.800 --> 0:12:13.280 involve an excess of thyroid hormone, they can cause things 0:12:13.360 --> 0:12:16.079 like tremors, weight loss, and low blood sugar, as well 0:12:16.120 --> 0:12:20.080 as a rapid heartbeat, and in extreme cases, can be fatal. 0:12:20.920 --> 0:12:23.320 It did not take long for people to realize that 0:12:23.400 --> 0:12:27.040 iodine could have a beneficial effect on goiter, though. In 0:12:27.080 --> 0:12:31.400 eighteen twenty one, Swiss physician Jef Freancois Quande published a 0:12:31.440 --> 0:12:34.559 paper detailing how he had reduced the size of goiter's 0:12:34.760 --> 0:12:40.000 by administering iodine. But Quondai didn't have a perfect process. 0:12:40.360 --> 0:12:44.439 His iodine treatments led to hyperthyroidism in some of his patients, 0:12:44.840 --> 0:12:47.640 and this continued to be the case for other researchers 0:12:47.679 --> 0:12:51.199 through much of the nineteenth century. Around the same time, 0:12:51.320 --> 0:12:56.000 French agricultural chemist Jean Beausingaul was also suggesting that iodine 0:12:56.080 --> 0:12:59.160 might offer a treatment for goiter That was based on 0:12:59.200 --> 0:13:02.880 a correlation observed between the prevalence of goiter and how 0:13:02.960 --> 0:13:06.800 much iodine was in soil samples in the eighteen fifties. 0:13:06.800 --> 0:13:11.840 Another French researcher, Caspar Adolf Chattez, similarly described a relationship 0:13:11.880 --> 0:13:15.200 between how much iodine was in the air drinking water 0:13:15.280 --> 0:13:18.679 and soil in a particular area and the incidence of 0:13:18.760 --> 0:13:24.520 goiter there. In areas with more iodine, goiter was less common. 0:13:25.640 --> 0:13:29.960 He also published works suggesting that chronically low iodine levels 0:13:30.040 --> 0:13:34.480 could cause chronic goiter, but his conclusions really weren't widely 0:13:34.520 --> 0:13:39.319 accepted because people questioned whether the minute amounts of iodine 0:13:39.360 --> 0:13:42.160 that he was describing really could have such a pronounced 0:13:42.240 --> 0:13:46.600 impact on a person's body. In eighteen ninety five, German 0:13:46.720 --> 0:13:50.640 chemist Eugen Bauman pinpointed the presence of iodine in the 0:13:50.640 --> 0:13:56.040 thyroid glands and isolated a physiologically active substance from within 0:13:56.080 --> 0:13:59.080 the glands, but he didn't get far on figuring out 0:13:59.200 --> 0:14:02.560 exactly what the substance was or how it functioned within 0:14:02.600 --> 0:14:05.280 the body, and he died the following year at the 0:14:05.280 --> 0:14:09.600 age of forty nine. In the early twentieth century, David 0:14:09.720 --> 0:14:14.880 Marine published work demonstrating a clear connection between iodine levels 0:14:14.880 --> 0:14:18.640 and thyroid function, but at first this was not in humans. 0:14:18.760 --> 0:14:23.760 He was studying other animals, including farmed brook trout. These 0:14:23.840 --> 0:14:26.200 brook trout seemed to be prone to some kind of 0:14:26.320 --> 0:14:31.360 thyroid dysfunction. Before Marine carried out these experiments, the swellings 0:14:31.400 --> 0:14:34.800 and lesions on these trout's thyroid glands were believed to 0:14:34.800 --> 0:14:38.200 be a form of carcinoma. He concluded that in a 0:14:38.240 --> 0:14:41.680 lot of cases this was an ordinary goiter except in 0:14:41.720 --> 0:14:44.640 a fish, and that it could be resolved just by 0:14:44.680 --> 0:14:49.040 adding iodine to their water supply. Marine started publishing this 0:14:49.120 --> 0:14:51.840 work in nineteen oh seven, and within about a decade 0:14:51.880 --> 0:14:56.000 he was studying the connection between iodine and goiter in humans. 0:14:56.760 --> 0:14:59.840 He carried out the first controlled human experiment to t 0:15:00.280 --> 0:15:04.200 this in Akron, Ohio. The test subjects included more than 0:15:04.240 --> 0:15:08.240 four thousand schoolgirls, with half of them receiving small doses 0:15:08.280 --> 0:15:12.320 of iodine and the other half not. Only five of 0:15:12.360 --> 0:15:16.040 the girls receiving iodine developed some kind of thyroid condition, 0:15:16.720 --> 0:15:19.600 but that number in the group who didn't receive iodine 0:15:19.880 --> 0:15:23.600 was four hundred and seventy five. His book on the subject, 0:15:23.640 --> 0:15:26.960 titled The Prevention of Simple Goiter in Man, was published 0:15:27.000 --> 0:15:32.720 in nineteen seventeen. The Akron experiment started in nineteen sixteen, 0:15:33.080 --> 0:15:35.680 and it ran in parallel to some work on goiter 0:15:35.760 --> 0:15:38.760 prevention that was going on in two places where goiter 0:15:39.000 --> 0:15:42.800 was highly prevalent was the country of Switzerland and the 0:15:42.840 --> 0:15:46.640 state of Michigan. Although these are on two different continents, 0:15:46.840 --> 0:15:49.640 both of them have very low levels of iodine in 0:15:49.680 --> 0:15:54.000 the soil. The work in Switzerland started just a bit earlier. 0:15:54.720 --> 0:15:58.400 In some areas of the country, goiter wasn't particularly prevalent, 0:15:58.760 --> 0:16:01.760 but according to a survey published by doctor Heinrich Bircher 0:16:01.800 --> 0:16:05.240 in eighteen eighty three, in one suburb of the capital 0:16:05.280 --> 0:16:08.920 city of Bern, ninety four percent of men had goiters. 0:16:09.480 --> 0:16:12.360 In the early twentieth century, as many as ten percent 0:16:12.440 --> 0:16:16.400 of babies born in Switzerland showed signs of congenital thyroid 0:16:16.440 --> 0:16:20.520 deficiency syndrome, and according to death certificates, goiter was the 0:16:20.560 --> 0:16:23.600 cause of death for more than fifteen hundred people there 0:16:23.600 --> 0:16:28.280 between nineteen eleven and nineteen twenty. Another four hundred sixty 0:16:28.280 --> 0:16:32.840 three people died of thyroid cancer during that period. Researchers 0:16:32.840 --> 0:16:36.720 had proposed various ideas to explain why so many people 0:16:36.800 --> 0:16:40.240 in Switzerland had goiter and why it was so much 0:16:40.320 --> 0:16:43.520 more prevalent in some places in Switzerland than in others. 0:16:44.280 --> 0:16:47.480 Some of these ideas involved eugenics and the idea that 0:16:47.520 --> 0:16:51.600 people who had goiter or the symptoms of hypothyroidism must 0:16:51.640 --> 0:16:56.960 have had bad breeding. Heinrich Hunziker proposed that Switzerland's rates 0:16:56.960 --> 0:17:00.200 of goiter were caused by a lack of iodie. 0:17:00.240 --> 0:17:01.520 In nineteen fourteen. 0:17:02.280 --> 0:17:04.680 There was again a lot of opposition to his ideas 0:17:04.680 --> 0:17:08.680 of iodine supplementation, due to fears that that supplementation might 0:17:08.760 --> 0:17:09.639 poison people. 0:17:10.720 --> 0:17:14.000 Even so, at least one person tried to test out 0:17:14.080 --> 0:17:18.080 Hunsicker's ideas. That was Auto Bayard, from the town of Valet. 0:17:18.920 --> 0:17:23.000 He mixed iodine into salt at five different concentrations and 0:17:23.040 --> 0:17:26.000 distributed it to five families who were living in a 0:17:26.040 --> 0:17:29.360 remote area where the train only ran in the warmer months. 0:17:30.040 --> 0:17:32.600 About seventy five percent of the children living in this 0:17:32.720 --> 0:17:37.199 area reportedly had in large thyroid glands. In addition to 0:17:37.240 --> 0:17:40.680 providing salt to these families, Bayard supplied salt for the 0:17:40.760 --> 0:17:44.600 village's animals and to the bakery. He delivered the salt 0:17:44.600 --> 0:17:47.680 before the train shut down for the winter of nineteen eighteen. 0:17:48.440 --> 0:17:50.840 When he returned there in the spring, he found that 0:17:50.880 --> 0:17:56.159 people's thyroid glands had dramatically improved, and nobody seemed to 0:17:56.200 --> 0:17:58.879 have been harmed by the iodine that had been added 0:17:58.880 --> 0:18:02.520 to the salt. Biard heard about the Akron experiment not 0:18:02.600 --> 0:18:05.280 long after this, and he repeated his experiment on a 0:18:05.400 --> 0:18:08.280 larger scale with the help of the Swiss Health Authority. 0:18:09.080 --> 0:18:12.280 Byard was invited to present his research to the Swiss 0:18:12.320 --> 0:18:17.199 Goiter Commission on January twenty first, nineteen twenty two. He 0:18:17.359 --> 0:18:20.880 and the Commission were not completely sure why adding iodine 0:18:20.920 --> 0:18:23.800 to the salt was so effective at treating goiter, but 0:18:23.880 --> 0:18:26.720 it definitely seemed to work, so the Commission wanted to 0:18:26.760 --> 0:18:30.920 try implementing it nationally. We mentioned up at the top 0:18:30.960 --> 0:18:34.399 of the show that governments around the world had regulated 0:18:34.520 --> 0:18:38.080 salt for centuries, and that was the case in Switzerland. 0:18:38.400 --> 0:18:42.920 Switzerland is more formally known as the Swiss Confederation. Today 0:18:42.960 --> 0:18:47.480 it comprises twenty six member states known as cantons. In 0:18:47.520 --> 0:18:50.760 the nineteeneens that number was slightly smaller, but each of 0:18:50.880 --> 0:18:54.359 these cantons had a monopoly on the sale of salt 0:18:54.400 --> 0:18:56.920 there going all the way back to the medieval period, 0:18:57.640 --> 0:19:00.760 so it wasn't possible for Switzerland and as a nation, 0:19:00.960 --> 0:19:04.440 to just mandate the sale or use of iodized salt 0:19:04.440 --> 0:19:07.720 across the whole country, or to make national changes to 0:19:07.760 --> 0:19:10.760 the salt supply. They had to advocate for doing this 0:19:10.880 --> 0:19:15.600 with each of the cantons individually. Hans Eggenberger, chief doctor 0:19:15.600 --> 0:19:18.399 in the town of Harrisau, became a vocal advocate for 0:19:18.440 --> 0:19:22.199 the use of iodized salt, spearheading efforts both within the 0:19:22.240 --> 0:19:26.280 government and as a public relations campaign. By June of 0:19:26.359 --> 0:19:29.480 nineteen twenty two, the Goiter Commission had recommended the use 0:19:29.480 --> 0:19:32.639 of iodized salt to all of the cantons, and the 0:19:32.680 --> 0:19:37.320 first deliveries of iodized salt took place at November. Michigan 0:19:37.440 --> 0:19:40.680 was facing really similar rates of goiter to Switzerland. In 0:19:40.720 --> 0:19:44.399 the early twentieth century, this part of the United States 0:19:44.480 --> 0:19:47.960 had been nicknamed the goiter Belt due to the prevalence 0:19:48.000 --> 0:19:52.160 of goiter and thyroid disease in Michigan and surrounding states. 0:19:52.520 --> 0:19:56.320 In nineteen eighteen, as Otto Bayard was working on his 0:19:56.440 --> 0:20:02.480 salt experiment, doctor Simon Levin was conducting physicals in Houghton County, Michigan. 0:20:03.280 --> 0:20:06.480 Levin reported that thirty percent of the men that he 0:20:06.600 --> 0:20:11.199 examined had an enlarged thyroid. It was estimated that more 0:20:11.240 --> 0:20:15.880 than twenty thousand men in northern Michigan alone were ineligible 0:20:15.880 --> 0:20:20.119 for military service because of their goiters and an enlarged thyroid. 0:20:20.160 --> 0:20:24.200 Gland was the most common reason for medical disqualification from 0:20:24.240 --> 0:20:27.840 military service in this part of the United States. Since 0:20:27.880 --> 0:20:30.560 the United States was involved in World War One, this 0:20:30.720 --> 0:20:33.200 was seen as an urgent issue. 0:20:33.320 --> 0:20:37.680 Health officials in Michigan expanded their focus beyond military physicals 0:20:37.720 --> 0:20:40.439 and conducted a follow up study in two towns in 0:20:40.520 --> 0:20:44.600 Houghton County for people aged one to sixty one. They 0:20:44.600 --> 0:20:46.800 found that more than sixty four percent of the people 0:20:46.840 --> 0:20:50.679 examined had some kind of goiter. Almost half of school 0:20:50.720 --> 0:20:53.639 children showed some evidence of thyroid dysfunction. 0:20:54.640 --> 0:20:58.320 Canadian American physician David Murray Cowie was the first professor 0:20:58.359 --> 0:21:02.120 of pediatrics at the Universe of Michigan. He had learned 0:21:02.119 --> 0:21:05.000 about the Swiss efforts to add iodine to salt, and 0:21:05.040 --> 0:21:09.080 he recommended a similar program to the Michigan State Medical Society. 0:21:09.119 --> 0:21:13.920 In nineteen twenty two, the Society established an advisory committee 0:21:13.920 --> 0:21:17.520 in its Pediatric section to focus on this project. This 0:21:17.640 --> 0:21:20.600 would lead to the first widespread use of a fortified 0:21:20.640 --> 0:21:23.760 food product in the United States. We're going to talk 0:21:23.880 --> 0:21:26.480 more about that after we paused for a sponsor break. 0:21:36.280 --> 0:21:38.800 There were a lot of reasons behind the decision to 0:21:38.840 --> 0:21:42.480 add iodine to salts. Rather than trying some other strategy 0:21:42.640 --> 0:21:47.639 to get iodine into people's diets. Various experiments involving iodine 0:21:47.720 --> 0:21:50.960 supplements in the late nineteenth and early twentieth century hadn't 0:21:51.000 --> 0:21:54.760 been really successful, Like there were iodine syrups that tasted 0:21:54.800 --> 0:21:58.600 disgusting so children didn't want to take them, or these 0:21:58.600 --> 0:22:01.720 were supplements that only needed to be administered every few months, 0:22:02.119 --> 0:22:05.639 so people would just forget about them. Meanwhile, salt was 0:22:05.640 --> 0:22:09.360 something that virtually everyone used in cooking, and its use 0:22:09.400 --> 0:22:13.240 didn't really vary much from season to season, unlike in 0:22:13.359 --> 0:22:16.639 earlier eras where the salt trade could involve long and 0:22:16.840 --> 0:22:19.720 arduous journeys, which I mean, I guess it still could 0:22:19.720 --> 0:22:22.960 in the early twentieth century, but most people had access 0:22:22.960 --> 0:22:25.879 to salt at a local store at a reasonable price, 0:22:26.560 --> 0:22:29.360 and unlike today, there wasn't a big public health focus 0:22:29.440 --> 0:22:33.560 on reducing salt intake due to sodium's connection to high 0:22:33.560 --> 0:22:37.400 blood pressure. Salt wasn't the only thing that people tried 0:22:37.440 --> 0:22:41.400 adding iodine to in the US, though. In Rochester, New York, 0:22:41.440 --> 0:22:43.600 there was a plan to add ionine to the drinking 0:22:43.680 --> 0:22:48.119 water that started on April twenty fourth, nineteen twenty three. 0:22:48.160 --> 0:22:51.320 This involved adding sodium iodide to the inflow of the 0:22:51.320 --> 0:22:55.320 city's reservoir in a project overseen by doctor George W. Goehler, 0:22:55.640 --> 0:22:59.679 who was Rochester's health officer. He had his own backstory 0:22:59.680 --> 0:23:04.560 that we not getting into, including apparently opposing pasteurization because 0:23:04.560 --> 0:23:07.439 he had seen such a reduction in milk boorn illnesses 0:23:07.480 --> 0:23:11.840 through his own inspection program. This effort to add iodine 0:23:11.840 --> 0:23:14.720 to the water was relatively effective, but it had some 0:23:14.880 --> 0:23:18.480 challenges like the amount of iodine that could be added 0:23:18.520 --> 0:23:21.320 to the reservoir was not enough to keep the average 0:23:21.400 --> 0:23:26.000 person's thyroid working well, at least not if they drank 0:23:26.040 --> 0:23:29.600 a typical amount of water, so people were advised to 0:23:29.680 --> 0:23:33.400 drink more tap water, as much as three times more 0:23:33.560 --> 0:23:37.000 than they were typically drinking. The level of iodine in 0:23:37.040 --> 0:23:40.320 the tap water also dropped really quickly after it was 0:23:40.359 --> 0:23:41.400 added to the reservoir. 0:23:42.280 --> 0:23:44.879 A lot of people also objected to the idea of 0:23:44.920 --> 0:23:49.200 something being added to their drinking water, including other water authorities. 0:23:49.800 --> 0:23:52.200 For example, a write up by the British Water Works 0:23:52.200 --> 0:23:55.920 Association set in part quote, it is contrary to ordinary 0:23:56.000 --> 0:23:59.760 medical teaching to force a whole population to drink doped 0:23:59.800 --> 0:24:03.480 water to the benefit of the minority. There were also 0:24:03.520 --> 0:24:06.639 several fires that appeared to be arson and threats that 0:24:06.640 --> 0:24:09.760 there would be more fires if this program was not stopped. 0:24:10.520 --> 0:24:13.640 Although the rate of goiter in and around Rochester did 0:24:13.680 --> 0:24:16.840 decline while this program was going on, it ended during 0:24:16.880 --> 0:24:20.000 the Great Depression, after a round of budget cuts and 0:24:20.080 --> 0:24:24.480 Goaler's retirement to return to Michigan. There was a proposal 0:24:24.520 --> 0:24:28.240 to pass a state law mandating the addition of iodine 0:24:28.280 --> 0:24:31.800 to salt, but there were a number of worries, in 0:24:31.840 --> 0:24:35.800 my opinion, well founded worries that people would object to 0:24:35.920 --> 0:24:39.199 a legal mandate that required something to be added to 0:24:39.240 --> 0:24:43.199 their food. So instead, health authorities in Michigan started a 0:24:43.240 --> 0:24:47.840 campaign of public education and a sort of industry pr 0:24:47.960 --> 0:24:51.640 campaign similar to what had happened in Switzerland, to convince 0:24:51.680 --> 0:24:55.280 all of the cantons to sell idise salt. This involved 0:24:55.280 --> 0:24:58.880 almost two hundred public health lectures that were carried out 0:24:58.920 --> 0:25:02.000 all over the state and work with the Michigan Salt 0:25:02.000 --> 0:25:05.959 Producers Association and outreach to the presidents of all the 0:25:06.000 --> 0:25:10.040 individual salt producers that were selling their products in Michigan. 0:25:10.600 --> 0:25:12.600 These folks were nicknamed the Saltmen. 0:25:13.880 --> 0:25:14.840 This became a. 0:25:14.840 --> 0:25:18.639 Huge cooperative effort between Michigan's public health workers and the 0:25:18.680 --> 0:25:22.720 salt industry, with David Marie Cowie being a major presence 0:25:22.800 --> 0:25:25.760 in all of it. Officials had to convince the salt 0:25:25.800 --> 0:25:29.400 industry that adding iodine wouldn't affect the quality of their product. 0:25:29.760 --> 0:25:32.640