1 00:00:01,320 --> 00:00:04,280 Speaker 1: Welcome to Stuff You Missed in History Class, a production 2 00:00:04,400 --> 00:00:14,520 Speaker 1: of iHeartRadio. Hello, and welcome to the podcast. I'm Tracy V. 3 00:00:14,640 --> 00:00:16,080 Speaker 1: Wilson and I'm Holly Frye. 4 00:00:16,960 --> 00:00:19,720 Speaker 2: Back at the beginning of May, I read an article 5 00:00:19,760 --> 00:00:23,560 Speaker 2: in the Washington Post called how the arrival of iodized 6 00:00:23,680 --> 00:00:27,560 Speaker 2: salt one hundred years ago changed America. And I was 7 00:00:27,600 --> 00:00:30,960 Speaker 2: immediately fascinated by this whole thing, And I also wanted 8 00:00:31,000 --> 00:00:34,720 Speaker 2: to learn more than a thousand word newspaper article could 9 00:00:34,720 --> 00:00:37,920 Speaker 2: tell me. I already knew, and I think maybe a 10 00:00:37,920 --> 00:00:41,000 Speaker 2: lot of folks already knew from something like elementary school 11 00:00:41,040 --> 00:00:45,479 Speaker 2: health class that iodine is added into table salt because 12 00:00:45,520 --> 00:00:50,120 Speaker 2: our bodies need that iodine for thyroid reasons. And I 13 00:00:50,200 --> 00:00:53,880 Speaker 2: also knew there are various people who, for whatever reason, 14 00:00:54,040 --> 00:00:57,240 Speaker 2: don't like iodized salt or don't want to use it, 15 00:00:57,320 --> 00:00:59,320 Speaker 2: and that was sort of the sum of my knowledge 16 00:00:59,320 --> 00:01:03,520 Speaker 2: about the iodide salt. And so reading this Washington Post article, 17 00:01:03,600 --> 00:01:07,319 Speaker 2: I didn't really grasp that adding the iodine to the 18 00:01:07,360 --> 00:01:10,240 Speaker 2: salt was not just like a nutritional nice to have. 19 00:01:10,920 --> 00:01:14,200 Speaker 2: They were not like well meaning public health people kind 20 00:01:14,240 --> 00:01:16,320 Speaker 2: of like, wouldn't it be great if everybody just had 21 00:01:16,440 --> 00:01:20,440 Speaker 2: enough iodine, just because it was to try to deal 22 00:01:20,480 --> 00:01:23,760 Speaker 2: with a problem that in some parts of the world 23 00:01:23,920 --> 00:01:29,400 Speaker 2: was really serious with chronic iodine deficiency. It was incredibly 24 00:01:29,480 --> 00:01:32,240 Speaker 2: widespread in some places, and that was causing a range 25 00:01:32,400 --> 00:01:36,360 Speaker 2: of actual health issues, not just wouldn't it be great 26 00:01:36,400 --> 00:01:37,600 Speaker 2: if we all got enough iodine. 27 00:01:38,280 --> 00:01:41,880 Speaker 1: So a complete history of salt would be its own episode, 28 00:01:41,959 --> 00:01:44,160 Speaker 1: or perhaps even more than one. You could even have 29 00:01:44,240 --> 00:01:47,040 Speaker 1: the story of salt as an entire podcast. I imagine. 30 00:01:47,680 --> 00:01:51,920 Speaker 1: Of course, edible salt or sodium chloride makes food more flavorful, 31 00:01:52,120 --> 00:01:55,360 Speaker 1: and it's an electrolyte that our bodies need to function correctly. 32 00:01:56,160 --> 00:02:00,520 Speaker 1: Salt can also be used to preserve food through salting, curing, brining, 33 00:02:00,640 --> 00:02:04,279 Speaker 1: or pickling, and there are lots of non dietary uses 34 00:02:04,320 --> 00:02:07,760 Speaker 1: for it as well. So for those and other reasons, 35 00:02:07,800 --> 00:02:10,959 Speaker 1: people have wanted and needed salt, going all the way 36 00:02:11,000 --> 00:02:15,440 Speaker 1: back to our earliest beginnings, cultures all around the world 37 00:02:15,520 --> 00:02:20,600 Speaker 1: have boiled or evaporated salt from water, including seawater and 38 00:02:20,720 --> 00:02:25,320 Speaker 1: water from salt lakes or mineral springs. Animals besides us, 39 00:02:25,400 --> 00:02:28,320 Speaker 1: need salt to often they get it from licking at 40 00:02:28,440 --> 00:02:32,160 Speaker 1: salt deposits. So people who are living farther inland could 41 00:02:32,200 --> 00:02:35,160 Speaker 1: sometimes find sources of salt by just watching what the 42 00:02:35,200 --> 00:02:39,959 Speaker 1: animals were doing, even if salt had no other uses. 43 00:02:40,240 --> 00:02:43,760 Speaker 1: Its importance in flavoring and preserving food has made it 44 00:02:43,840 --> 00:02:47,400 Speaker 1: highly sought after all over the world for basically all 45 00:02:47,480 --> 00:02:51,360 Speaker 1: of history. Some of the world's earliest trade networks were, 46 00:02:51,440 --> 00:02:55,080 Speaker 1: of course, salt roads, and many of the earliest governments, 47 00:02:55,160 --> 00:02:59,440 Speaker 1: established thousands of years ago, regulated the salt trade and 48 00:02:59,560 --> 00:03:05,800 Speaker 1: establish salt stockpiles. Iodine is not nearly as abundant assault, 49 00:03:05,880 --> 00:03:10,480 Speaker 1: but it is similarly critical. People and all other vertebrate 50 00:03:10,560 --> 00:03:15,040 Speaker 1: animals need iodine for our bodies to function properly. Specifically, 51 00:03:15,240 --> 00:03:19,000 Speaker 1: the body uses iodine to make thyroid hormones, and thyroid 52 00:03:19,040 --> 00:03:23,600 Speaker 1: hormones regulate a number of body functions, including growth and metabolism, 53 00:03:23,919 --> 00:03:27,800 Speaker 1: affecting virtually every cell in the body. The iodine we 54 00:03:27,919 --> 00:03:30,920 Speaker 1: consume moves from the digestive system to the blood and 55 00:03:31,000 --> 00:03:34,840 Speaker 1: from there to the thyroid gland, which produces those hormones. 56 00:03:35,680 --> 00:03:39,000 Speaker 2: People only need a little bit of iodine. In the 57 00:03:39,160 --> 00:03:42,680 Speaker 2: United States, the recommended daily allowance is only one hundred 58 00:03:42,720 --> 00:03:46,720 Speaker 2: and fifty micrograms a day for adults. It's roughly half 59 00:03:46,800 --> 00:03:51,320 Speaker 2: that For babies and children, the recommended daily allowance increases 60 00:03:51,360 --> 00:03:54,840 Speaker 2: to two hundred and twenty micrograms during pregnancy and two 61 00:03:54,960 --> 00:03:59,119 Speaker 2: hundred and ninety micrograms while lactating. But whether people can 62 00:03:59,160 --> 00:04:03,240 Speaker 2: get that much eye iodine without access to fortified foods 63 00:04:03,360 --> 00:04:08,040 Speaker 2: like iodized salt varies widely depending on where they live. 64 00:04:08,800 --> 00:04:12,640 Speaker 2: There's iodine in seawater, and it's in the Earth's crust, 65 00:04:12,800 --> 00:04:15,840 Speaker 2: but exactly how much iodine there is in a particular 66 00:04:15,880 --> 00:04:19,039 Speaker 2: location depends on things like how close it is to 67 00:04:19,120 --> 00:04:22,880 Speaker 2: the sea and geological changes that have taken place over 68 00:04:23,040 --> 00:04:24,800 Speaker 2: thousands and thousands of years. 69 00:04:25,600 --> 00:04:28,960 Speaker 1: The presence of iodine in seawater means that various types 70 00:04:29,000 --> 00:04:32,880 Speaker 1: of seaweed and marine animals are also high in iodine, 71 00:04:33,240 --> 00:04:36,440 Speaker 1: so people living in an island nation like Japan, where 72 00:04:36,480 --> 00:04:39,560 Speaker 1: the traditional diet includes a lot of seafood and seaweed 73 00:04:40,080 --> 00:04:42,640 Speaker 1: may be able to get enough iodine through their regular 74 00:04:42,720 --> 00:04:45,080 Speaker 1: diet without some kind of supplementation. 75 00:04:46,560 --> 00:04:51,160 Speaker 2: Generally speaking, things get trickier farther inland. How much iodine 76 00:04:51,200 --> 00:04:54,599 Speaker 2: is available to people and animals depends on how much 77 00:04:54,600 --> 00:04:57,920 Speaker 2: of it is present in the soil, so, for example, 78 00:04:58,080 --> 00:05:01,040 Speaker 2: cows grazing on a pasture near the sea, where the 79 00:05:01,040 --> 00:05:04,279 Speaker 2: iodine in the soil is replenished by the spray blowing 80 00:05:04,360 --> 00:05:07,080 Speaker 2: in from the ocean, they might get enough iodine, and 81 00:05:07,120 --> 00:05:09,400 Speaker 2: that means there would also be iodine in their milk. 82 00:05:10,000 --> 00:05:14,120 Speaker 2: But high altitudes places where there are recurring floods or 83 00:05:14,160 --> 00:05:18,880 Speaker 2: cycles of glaciers melting and refreezing, those places typically have 84 00:05:19,200 --> 00:05:22,400 Speaker 2: very little iodine in the soil, so without some kind 85 00:05:22,440 --> 00:05:26,240 Speaker 2: of supplementation, people and animals living there cannot get enough 86 00:05:26,279 --> 00:05:27,600 Speaker 2: iodine in their diets. 87 00:05:28,120 --> 00:05:30,919 Speaker 1: This isn't only a problem for humans who rely on 88 00:05:30,960 --> 00:05:35,719 Speaker 1: these animals for food. Iodine deficiency in livestock is connected 89 00:05:35,720 --> 00:05:38,640 Speaker 1: to things like still births, the deaths of young, and 90 00:05:38,760 --> 00:05:42,559 Speaker 1: lower production of eggs and milk. As a side note, 91 00:05:42,640 --> 00:05:45,320 Speaker 1: in today's world, some of the iodine and milk doesn't 92 00:05:45,360 --> 00:05:48,280 Speaker 1: actually come from what the cows are eating. It's from 93 00:05:48,320 --> 00:05:52,159 Speaker 1: the use of iodine as an antiseptic or sterilizer, both 94 00:05:52,200 --> 00:05:55,080 Speaker 1: on the cow's utters and on equipment that's used in 95 00:05:55,080 --> 00:05:56,040 Speaker 1: the dairy industry. 96 00:05:56,800 --> 00:05:59,279 Speaker 2: There are also some things that can interfere with the 97 00:05:59,279 --> 00:06:03,920 Speaker 2: bodies of bil to absorb iodine, including compounds found in 98 00:06:04,000 --> 00:06:08,800 Speaker 2: cassava and millet, and some chemical pollutants. So a person 99 00:06:09,080 --> 00:06:12,240 Speaker 2: living in an area where the soil is low in iodine, 100 00:06:12,600 --> 00:06:15,560 Speaker 2: or whose diet includes a lot of those foods somebody 101 00:06:15,560 --> 00:06:18,599 Speaker 2: who's exposed to these kinds of pollutants. These people could 102 00:06:18,640 --> 00:06:22,840 Speaker 2: have even more difficulty getting enough iodine In people. 103 00:06:23,000 --> 00:06:26,160 Speaker 1: Iodine deficiency can lead to a number of health issues. 104 00:06:26,720 --> 00:06:29,280 Speaker 1: As we said earlier, the body needs iodine to make 105 00:06:29,320 --> 00:06:33,320 Speaker 1: thyroid hormones. If the thyroid gland isn't getting enough iodine 106 00:06:33,320 --> 00:06:36,440 Speaker 1: to do this, it enlarges as it tries to filter 107 00:06:36,600 --> 00:06:40,760 Speaker 1: more iodine from the blood. This enlarged thyroid gland is 108 00:06:40,800 --> 00:06:43,520 Speaker 1: called a goiter, and a goiter can put pressure on 109 00:06:43,560 --> 00:06:45,840 Speaker 1: the blood vessels in the neck and on the trachea. 110 00:06:46,680 --> 00:06:50,039 Speaker 1: There are other things that can cause goiter, including autoimmune 111 00:06:50,080 --> 00:06:54,920 Speaker 1: disorders like graves disease, thyroid nodules, and cancers, but iodine 112 00:06:54,920 --> 00:06:59,200 Speaker 1: deficiency is the most common cause of goiter worldwide, and yes, 113 00:06:59,440 --> 00:07:02,520 Speaker 1: non human and animals can also develop goiter. 114 00:07:02,960 --> 00:07:04,320 Speaker 3: Without enough iodine. 115 00:07:04,360 --> 00:07:07,599 Speaker 2: The body also can't make enough thyroid hormone that leads 116 00:07:07,640 --> 00:07:14,720 Speaker 2: to hypothyroidism. Symptoms and effects of hypothyroidism include things like fatigue, listlessness, 117 00:07:14,800 --> 00:07:20,600 Speaker 2: difficulty concentrating, dry skin, feeling cold all the time, depression, 118 00:07:21,080 --> 00:07:26,480 Speaker 2: irregular menstrual periods, among other things. Iodine and thyroid hormones 119 00:07:26,520 --> 00:07:30,080 Speaker 2: also play an important role in brain development in utero. 120 00:07:30,200 --> 00:07:33,920 Speaker 2: Iodine deficiency during pregnancy can lead to babies being born 121 00:07:33,960 --> 00:07:38,080 Speaker 2: with congenital iodine deficiency syndrome, which a startling number of 122 00:07:38,120 --> 00:07:41,000 Speaker 2: sources are still right now in the year twenty twenty 123 00:07:41,080 --> 00:07:45,160 Speaker 2: four while we record this describing using the word cretinism, 124 00:07:45,400 --> 00:07:49,360 Speaker 2: even though at this point that term has deeply insulting connotations. 125 00:07:50,160 --> 00:07:55,160 Speaker 2: Congenital iodine deficiency syndrome can lead to developmental disabilities, deafness 126 00:07:55,160 --> 00:08:00,120 Speaker 2: and inability to speak, and muscular skeletal issues. Treatment with 127 00:08:00,160 --> 00:08:04,320 Speaker 2: iodine can resolve many of the issues associated with hypothyroidism, 128 00:08:04,640 --> 00:08:08,280 Speaker 2: including the physical changes in babies born with congenital iodine 129 00:08:08,320 --> 00:08:12,360 Speaker 2: deficiency syndrome, but not the damage to the brain that 130 00:08:12,440 --> 00:08:17,840 Speaker 2: takes place during fetal development. Iodine wasn't discovered until the 131 00:08:17,920 --> 00:08:21,200 Speaker 2: nineteenth century, but people in various parts of the world 132 00:08:21,280 --> 00:08:24,960 Speaker 2: connected foods that are high in iodine with the prevention 133 00:08:25,080 --> 00:08:28,960 Speaker 2: and treatment of goiter thousands of years ago. Documents from 134 00:08:29,040 --> 00:08:32,600 Speaker 2: China dating back to about thirty six hundred BCE describe 135 00:08:32,640 --> 00:08:37,160 Speaker 2: a reduction in goiter after eating seaweed or burned sea sponge. 136 00:08:37,760 --> 00:08:40,840 Speaker 2: Seaweed and sea sponge continued to show up in medical 137 00:08:40,880 --> 00:08:45,959 Speaker 2: texts in Asia, Europe, and Northern Africa afterward. Ierveateic texts 138 00:08:45,960 --> 00:08:49,360 Speaker 2: from the Indian subcontinent dating back to about fourteen hundred 139 00:08:49,360 --> 00:08:56,000 Speaker 2: BCE also include descriptions of hyperthyroidism and hypothyroidism, with treatments 140 00:08:56,000 --> 00:09:01,000 Speaker 2: for hypothyroidism including things like milk, various grains, and bladder rack, 141 00:09:01,120 --> 00:09:05,720 Speaker 2: which is a type of seaweed. Overall, earlier medical writers 142 00:09:05,800 --> 00:09:09,880 Speaker 2: didn't know exactly what caused goiter. For example, those same 143 00:09:10,040 --> 00:09:14,480 Speaker 2: Aervedic texts conclude that goiter was caused by edema, and 144 00:09:14,600 --> 00:09:18,000 Speaker 2: various physicians throughout history have blamed goiter on a range 145 00:09:18,000 --> 00:09:22,080 Speaker 2: of illnesses, poisons, and even tumors. But there are also 146 00:09:22,120 --> 00:09:25,480 Speaker 2: written records of people making a connection between goiter and 147 00:09:25,520 --> 00:09:31,120 Speaker 2: the symptoms of hypothyroidism like fatigue and difficulty concentrating. In 148 00:09:31,160 --> 00:09:35,120 Speaker 2: the tenth century, Arab historian and geographer Al mas Udi 149 00:09:35,320 --> 00:09:40,440 Speaker 2: described Europeans as having quote large bodies, dull understanding, and 150 00:09:40,520 --> 00:09:44,160 Speaker 2: heavy tongues, which is often interpreted as a reference to 151 00:09:44,240 --> 00:09:49,679 Speaker 2: how many people had hypothyroidism. In the sixteenth century. Paracelsus 152 00:09:49,720 --> 00:09:53,160 Speaker 2: also made a connection between parents with goiter and children 153 00:09:53,200 --> 00:09:57,600 Speaker 2: born with developmental delays and disabilities. People started to get 154 00:09:57,600 --> 00:10:02,079 Speaker 2: a clearer understanding of the relationship but between goiter, thyroid hormone, 155 00:10:02,120 --> 00:10:05,640 Speaker 2: and iodine after iodine was discovered in the nineteenth century. 156 00:10:06,120 --> 00:10:14,400 Speaker 2: We'll have more on that after a sponsor break. In 157 00:10:14,720 --> 00:10:19,600 Speaker 2: eighteen eleven, French pharmacist and chemist Bernon Courtois was working 158 00:10:19,600 --> 00:10:24,360 Speaker 2: with seaweed at his father's saltpeter factory. This process involved 159 00:10:24,400 --> 00:10:27,319 Speaker 2: burning the seaweed to produce soda ash and then adding 160 00:10:27,360 --> 00:10:31,000 Speaker 2: sulfuric acid to it. One day, by accident, he added 161 00:10:31,040 --> 00:10:35,320 Speaker 2: too much sulfuric acid. In the words of Humphrey Davy, 162 00:10:35,440 --> 00:10:40,960 Speaker 2: this produced quote a beautiful violet vapor. Courtois was not 163 00:10:41,000 --> 00:10:43,600 Speaker 2: sure what this vapor was, but he called it by 164 00:10:43,640 --> 00:10:48,000 Speaker 2: the Greek word iodes, meaning violet. He didn't have time 165 00:10:48,120 --> 00:10:50,960 Speaker 2: to really experiment with this, so he gave a sample 166 00:10:51,080 --> 00:10:52,960 Speaker 2: to Joseph Luis Gaerusac. 167 00:10:53,520 --> 00:10:54,520 Speaker 3: We talked about. 168 00:10:54,280 --> 00:10:57,319 Speaker 2: This in our recent episode on Humphrey Davy, Davy and 169 00:10:57,520 --> 00:11:02,200 Speaker 2: Gaelusac each described iodine as an element in eighteen thirteen. 170 00:11:02,640 --> 00:11:05,199 Speaker 2: They made those descriptions about a week apart, and then 171 00:11:05,200 --> 00:11:07,400 Speaker 2: they had an argument about who should get the credit 172 00:11:07,440 --> 00:11:07,720 Speaker 2: for it. 173 00:11:08,440 --> 00:11:12,160 Speaker 1: Like so many other newly discovered substances, once it had 174 00:11:12,160 --> 00:11:16,280 Speaker 1: been identified and isolated, iodine made its way into medicines 175 00:11:16,320 --> 00:11:20,000 Speaker 1: meant to treat all kinds of things. Of course, it 176 00:11:20,040 --> 00:11:22,520 Speaker 1: didn't have an effect on most of them, and this 177 00:11:22,679 --> 00:11:26,080 Speaker 1: experimental iodine treatment also carried the risk of what came 178 00:11:26,120 --> 00:11:30,400 Speaker 1: to be known as the yod Basidou phenomenon. Yaod is 179 00:11:30,440 --> 00:11:34,040 Speaker 1: the German word for iodine, and Carl Adolf von Basidu 180 00:11:34,200 --> 00:11:37,080 Speaker 1: was the nineteenth century German doctor who worked with it. 181 00:11:37,760 --> 00:11:42,679 Speaker 1: He was reportedly the first person to describe thyrotoxicosis, which 182 00:11:42,720 --> 00:11:45,800 Speaker 1: occurs when there is too much thyroid hormone circulating in 183 00:11:45,840 --> 00:11:50,440 Speaker 1: a person's body. The yod bazidoo effect is thyrotoxicosis in 184 00:11:50,480 --> 00:11:53,400 Speaker 1: response to treatment with iodine. 185 00:11:53,559 --> 00:11:58,520 Speaker 2: As a note, sometimes the terms thyrotoxicosis and hyperthyroidism are 186 00:11:58,600 --> 00:12:02,040 Speaker 2: used interchangeably, but they're there are some slight nuances between 187 00:12:02,080 --> 00:12:05,080 Speaker 2: these two terms. Those nuances are a little outside the 188 00:12:05,120 --> 00:12:09,680 Speaker 2: scope of a generalist history podcast. Both of them however, 189 00:12:09,800 --> 00:12:13,280 Speaker 2: involve an excess of thyroid hormone, they can cause things 190 00:12:13,360 --> 00:12:16,079 Speaker 2: like tremors, weight loss, and low blood sugar, as well 191 00:12:16,120 --> 00:12:20,080 Speaker 2: as a rapid heartbeat, and in extreme cases, can be fatal. 192 00:12:20,920 --> 00:12:23,320 Speaker 2: It did not take long for people to realize that 193 00:12:23,400 --> 00:12:27,040 Speaker 2: iodine could have a beneficial effect on goiter, though. In 194 00:12:27,080 --> 00:12:31,400 Speaker 2: eighteen twenty one, Swiss physician Jef Freancois Quande published a 195 00:12:31,440 --> 00:12:34,559 Speaker 2: paper detailing how he had reduced the size of goiter's 196 00:12:34,760 --> 00:12:40,000 Speaker 2: by administering iodine. But Quondai didn't have a perfect process. 197 00:12:40,360 --> 00:12:44,439 Speaker 2: His iodine treatments led to hyperthyroidism in some of his patients, 198 00:12:44,840 --> 00:12:47,640 Speaker 2: and this continued to be the case for other researchers 199 00:12:47,679 --> 00:12:51,199 Speaker 2: through much of the nineteenth century. Around the same time, 200 00:12:51,320 --> 00:12:56,000 Speaker 2: French agricultural chemist Jean Beausingaul was also suggesting that iodine 201 00:12:56,080 --> 00:12:59,160 Speaker 2: might offer a treatment for goiter That was based on 202 00:12:59,200 --> 00:13:02,880 Speaker 2: a correlation observed between the prevalence of goiter and how 203 00:13:02,960 --> 00:13:06,800 Speaker 2: much iodine was in soil samples in the eighteen fifties. 204 00:13:06,800 --> 00:13:11,840 Speaker 2: Another French researcher, Caspar Adolf Chattez, similarly described a relationship 205 00:13:11,880 --> 00:13:15,200 Speaker 2: between how much iodine was in the air drinking water 206 00:13:15,280 --> 00:13:18,679 Speaker 2: and soil in a particular area and the incidence of 207 00:13:18,760 --> 00:13:24,520 Speaker 2: goiter there. In areas with more iodine, goiter was less common. 208 00:13:25,640 --> 00:13:29,960 Speaker 2: He also published works suggesting that chronically low iodine levels 209 00:13:30,040 --> 00:13:34,480 Speaker 2: could cause chronic goiter, but his conclusions really weren't widely 210 00:13:34,520 --> 00:13:39,319 Speaker 2: accepted because people questioned whether the minute amounts of iodine 211 00:13:39,360 --> 00:13:42,160 Speaker 2: that he was describing really could have such a pronounced 212 00:13:42,240 --> 00:13:46,600 Speaker 2: impact on a person's body. In eighteen ninety five, German 213 00:13:46,720 --> 00:13:50,640 Speaker 2: chemist Eugen Bauman pinpointed the presence of iodine in the 214 00:13:50,640 --> 00:13:56,040 Speaker 2: thyroid glands and isolated a physiologically active substance from within 215 00:13:56,080 --> 00:13:59,080 Speaker 2: the glands, but he didn't get far on figuring out 216 00:13:59,200 --> 00:14:02,560 Speaker 2: exactly what the substance was or how it functioned within 217 00:14:02,600 --> 00:14:05,280 Speaker 2: the body, and he died the following year at the 218 00:14:05,280 --> 00:14:09,600 Speaker 2: age of forty nine. In the early twentieth century, David 219 00:14:09,720 --> 00:14:14,880 Speaker 2: Marine published work demonstrating a clear connection between iodine levels 220 00:14:14,880 --> 00:14:18,640 Speaker 2: and thyroid function, but at first this was not in humans. 221 00:14:18,760 --> 00:14:23,760 Speaker 2: He was studying other animals, including farmed brook trout. These 222 00:14:23,840 --> 00:14:26,200 Speaker 2: brook trout seemed to be prone to some kind of 223 00:14:26,320 --> 00:14:31,360 Speaker 2: thyroid dysfunction. Before Marine carried out these experiments, the swellings 224 00:14:31,400 --> 00:14:34,800 Speaker 2: and lesions on these trout's thyroid glands were believed to 225 00:14:34,800 --> 00:14:38,200 Speaker 2: be a form of carcinoma. He concluded that in a 226 00:14:38,240 --> 00:14:41,680 Speaker 2: lot of cases this was an ordinary goiter except in 227 00:14:41,720 --> 00:14:44,640 Speaker 2: a fish, and that it could be resolved just by 228 00:14:44,680 --> 00:14:49,040 Speaker 2: adding iodine to their water supply. Marine started publishing this 229 00:14:49,120 --> 00:14:51,840 Speaker 2: work in nineteen oh seven, and within about a decade 230 00:14:51,880 --> 00:14:56,000 Speaker 2: he was studying the connection between iodine and goiter in humans. 231 00:14:56,760 --> 00:14:59,840 Speaker 2: He carried out the first controlled human experiment to t 232 00:15:00,280 --> 00:15:04,200 Speaker 2: this in Akron, Ohio. The test subjects included more than 233 00:15:04,240 --> 00:15:08,240 Speaker 2: four thousand schoolgirls, with half of them receiving small doses 234 00:15:08,280 --> 00:15:12,320 Speaker 2: of iodine and the other half not. Only five of 235 00:15:12,360 --> 00:15:16,040 Speaker 2: the girls receiving iodine developed some kind of thyroid condition, 236 00:15:16,720 --> 00:15:19,600 Speaker 2: but that number in the group who didn't receive iodine 237 00:15:19,880 --> 00:15:23,600 Speaker 2: was four hundred and seventy five. His book on the subject, 238 00:15:23,640 --> 00:15:26,960 Speaker 2: titled The Prevention of Simple Goiter in Man, was published 239 00:15:27,000 --> 00:15:32,720 Speaker 2: in nineteen seventeen. The Akron experiment started in nineteen sixteen, 240 00:15:33,080 --> 00:15:35,680 Speaker 2: and it ran in parallel to some work on goiter 241 00:15:35,760 --> 00:15:38,760 Speaker 2: prevention that was going on in two places where goiter 242 00:15:39,000 --> 00:15:42,800 Speaker 2: was highly prevalent was the country of Switzerland and the 243 00:15:42,840 --> 00:15:46,640 Speaker 2: state of Michigan. Although these are on two different continents, 244 00:15:46,840 --> 00:15:49,640 Speaker 2: both of them have very low levels of iodine in 245 00:15:49,680 --> 00:15:54,000 Speaker 2: the soil. The work in Switzerland started just a bit earlier. 246 00:15:54,720 --> 00:15:58,400 Speaker 2: In some areas of the country, goiter wasn't particularly prevalent, 247 00:15:58,760 --> 00:16:01,760 Speaker 2: but according to a survey published by doctor Heinrich Bircher 248 00:16:01,800 --> 00:16:05,240 Speaker 2: in eighteen eighty three, in one suburb of the capital 249 00:16:05,280 --> 00:16:08,920 Speaker 2: city of Bern, ninety four percent of men had goiters. 250 00:16:09,480 --> 00:16:12,360 Speaker 2: In the early twentieth century, as many as ten percent 251 00:16:12,440 --> 00:16:16,400 Speaker 2: of babies born in Switzerland showed signs of congenital thyroid 252 00:16:16,440 --> 00:16:20,520 Speaker 2: deficiency syndrome, and according to death certificates, goiter was the 253 00:16:20,560 --> 00:16:23,600 Speaker 2: cause of death for more than fifteen hundred people there 254 00:16:23,600 --> 00:16:28,280 Speaker 2: between nineteen eleven and nineteen twenty. Another four hundred sixty 255 00:16:28,280 --> 00:16:32,840 Speaker 2: three people died of thyroid cancer during that period. Researchers 256 00:16:32,840 --> 00:16:36,720 Speaker 2: had proposed various ideas to explain why so many people 257 00:16:36,800 --> 00:16:40,240 Speaker 2: in Switzerland had goiter and why it was so much 258 00:16:40,320 --> 00:16:43,520 Speaker 2: more prevalent in some places in Switzerland than in others. 259 00:16:44,280 --> 00:16:47,480 Speaker 2: Some of these ideas involved eugenics and the idea that 260 00:16:47,520 --> 00:16:51,600 Speaker 2: people who had goiter or the symptoms of hypothyroidism must 261 00:16:51,640 --> 00:16:56,960 Speaker 2: have had bad breeding. Heinrich Hunziker proposed that Switzerland's rates 262 00:16:56,960 --> 00:17:00,200 Speaker 2: of goiter were caused by a lack of iodie. 263 00:17:00,240 --> 00:17:01,520 Speaker 3: In nineteen fourteen. 264 00:17:02,280 --> 00:17:04,680 Speaker 2: There was again a lot of opposition to his ideas 265 00:17:04,680 --> 00:17:08,680 Speaker 2: of iodine supplementation, due to fears that that supplementation might 266 00:17:08,760 --> 00:17:09,639 Speaker 2: poison people. 267 00:17:10,720 --> 00:17:14,000 Speaker 1: Even so, at least one person tried to test out 268 00:17:14,080 --> 00:17:18,080 Speaker 1: Hunsicker's ideas. That was Auto Bayard, from the town of Valet. 269 00:17:18,920 --> 00:17:23,000 Speaker 1: He mixed iodine into salt at five different concentrations and 270 00:17:23,040 --> 00:17:26,000 Speaker 1: distributed it to five families who were living in a 271 00:17:26,040 --> 00:17:29,360 Speaker 1: remote area where the train only ran in the warmer months. 272 00:17:30,040 --> 00:17:32,600 Speaker 1: About seventy five percent of the children living in this 273 00:17:32,720 --> 00:17:37,199 Speaker 1: area reportedly had in large thyroid glands. In addition to 274 00:17:37,240 --> 00:17:40,680 Speaker 1: providing salt to these families, Bayard supplied salt for the 275 00:17:40,760 --> 00:17:44,600 Speaker 1: village's animals and to the bakery. He delivered the salt 276 00:17:44,600 --> 00:17:47,680 Speaker 1: before the train shut down for the winter of nineteen eighteen. 277 00:17:48,440 --> 00:17:50,840 Speaker 2: When he returned there in the spring, he found that 278 00:17:50,880 --> 00:17:56,159 Speaker 2: people's thyroid glands had dramatically improved, and nobody seemed to 279 00:17:56,200 --> 00:17:58,879 Speaker 2: have been harmed by the iodine that had been added 280 00:17:58,880 --> 00:18:02,520 Speaker 2: to the salt. Biard heard about the Akron experiment not 281 00:18:02,600 --> 00:18:05,280 Speaker 2: long after this, and he repeated his experiment on a 282 00:18:05,400 --> 00:18:08,280 Speaker 2: larger scale with the help of the Swiss Health Authority. 283 00:18:09,080 --> 00:18:12,280 Speaker 2: Byard was invited to present his research to the Swiss 284 00:18:12,320 --> 00:18:17,199 Speaker 2: Goiter Commission on January twenty first, nineteen twenty two. He 285 00:18:17,359 --> 00:18:20,880 Speaker 2: and the Commission were not completely sure why adding iodine 286 00:18:20,920 --> 00:18:23,800 Speaker 2: to the salt was so effective at treating goiter, but 287 00:18:23,880 --> 00:18:26,720 Speaker 2: it definitely seemed to work, so the Commission wanted to 288 00:18:26,760 --> 00:18:30,920 Speaker 2: try implementing it nationally. We mentioned up at the top 289 00:18:30,960 --> 00:18:34,399 Speaker 2: of the show that governments around the world had regulated 290 00:18:34,520 --> 00:18:38,080 Speaker 2: salt for centuries, and that was the case in Switzerland. 291 00:18:38,400 --> 00:18:42,920 Speaker 2: Switzerland is more formally known as the Swiss Confederation. Today 292 00:18:42,960 --> 00:18:47,480 Speaker 2: it comprises twenty six member states known as cantons. In 293 00:18:47,520 --> 00:18:50,760 Speaker 2: the nineteeneens that number was slightly smaller, but each of 294 00:18:50,880 --> 00:18:54,359 Speaker 2: these cantons had a monopoly on the sale of salt 295 00:18:54,400 --> 00:18:56,920 Speaker 2: there going all the way back to the medieval period, 296 00:18:57,640 --> 00:19:00,760 Speaker 2: so it wasn't possible for Switzerland and as a nation, 297 00:19:00,960 --> 00:19:04,440 Speaker 2: to just mandate the sale or use of iodized salt 298 00:19:04,440 --> 00:19:07,720 Speaker 2: across the whole country, or to make national changes to 299 00:19:07,760 --> 00:19:10,760 Speaker 2: the salt supply. They had to advocate for doing this 300 00:19:10,880 --> 00:19:15,600 Speaker 2: with each of the cantons individually. Hans Eggenberger, chief doctor 301 00:19:15,600 --> 00:19:18,399 Speaker 2: in the town of Harrisau, became a vocal advocate for 302 00:19:18,440 --> 00:19:22,199 Speaker 2: the use of iodized salt, spearheading efforts both within the 303 00:19:22,240 --> 00:19:26,280 Speaker 2: government and as a public relations campaign. By June of 304 00:19:26,359 --> 00:19:29,480 Speaker 2: nineteen twenty two, the Goiter Commission had recommended the use 305 00:19:29,480 --> 00:19:32,639 Speaker 2: of iodized salt to all of the cantons, and the 306 00:19:32,680 --> 00:19:37,320 Speaker 2: first deliveries of iodized salt took place at November. Michigan 307 00:19:37,440 --> 00:19:40,680 Speaker 2: was facing really similar rates of goiter to Switzerland. In 308 00:19:40,720 --> 00:19:44,399 Speaker 2: the early twentieth century, this part of the United States 309 00:19:44,480 --> 00:19:47,960 Speaker 2: had been nicknamed the goiter Belt due to the prevalence 310 00:19:48,000 --> 00:19:52,160 Speaker 2: of goiter and thyroid disease in Michigan and surrounding states. 311 00:19:52,520 --> 00:19:56,320 Speaker 2: In nineteen eighteen, as Otto Bayard was working on his 312 00:19:56,440 --> 00:20:02,480 Speaker 2: salt experiment, doctor Simon Levin was conducting physicals in Houghton County, Michigan. 313 00:20:03,280 --> 00:20:06,480 Speaker 2: Levin reported that thirty percent of the men that he 314 00:20:06,600 --> 00:20:11,199 Speaker 2: examined had an enlarged thyroid. It was estimated that more 315 00:20:11,240 --> 00:20:15,880 Speaker 2: than twenty thousand men in northern Michigan alone were ineligible 316 00:20:15,880 --> 00:20:20,119 Speaker 2: for military service because of their goiters and an enlarged thyroid. 317 00:20:20,160 --> 00:20:24,200 Speaker 2: Gland was the most common reason for medical disqualification from 318 00:20:24,240 --> 00:20:27,840 Speaker 2: military service in this part of the United States. Since 319 00:20:27,880 --> 00:20:30,560 Speaker 2: the United States was involved in World War One, this 320 00:20:30,720 --> 00:20:33,200 Speaker 2: was seen as an urgent issue. 321 00:20:33,320 --> 00:20:37,680 Speaker 1: Health officials in Michigan expanded their focus beyond military physicals 322 00:20:37,720 --> 00:20:40,439 Speaker 1: and conducted a follow up study in two towns in 323 00:20:40,520 --> 00:20:44,600 Speaker 1: Houghton County for people aged one to sixty one. They 324 00:20:44,600 --> 00:20:46,800 Speaker 1: found that more than sixty four percent of the people 325 00:20:46,840 --> 00:20:50,679 Speaker 1: examined had some kind of goiter. Almost half of school 326 00:20:50,720 --> 00:20:53,639 Speaker 1: children showed some evidence of thyroid dysfunction. 327 00:20:54,640 --> 00:20:58,320 Speaker 2: Canadian American physician David Murray Cowie was the first professor 328 00:20:58,359 --> 00:21:02,120 Speaker 2: of pediatrics at the Universe of Michigan. He had learned 329 00:21:02,119 --> 00:21:05,000 Speaker 2: about the Swiss efforts to add iodine to salt, and 330 00:21:05,040 --> 00:21:09,080 Speaker 2: he recommended a similar program to the Michigan State Medical Society. 331 00:21:09,119 --> 00:21:13,920 Speaker 2: In nineteen twenty two, the Society established an advisory committee 332 00:21:13,920 --> 00:21:17,520 Speaker 2: in its Pediatric section to focus on this project. This 333 00:21:17,640 --> 00:21:20,600 Speaker 2: would lead to the first widespread use of a fortified 334 00:21:20,640 --> 00:21:23,760 Speaker 2: food product in the United States. We're going to talk 335 00:21:23,880 --> 00:21:26,480 Speaker 2: more about that after we paused for a sponsor break. 336 00:21:36,280 --> 00:21:38,800 Speaker 2: There were a lot of reasons behind the decision to 337 00:21:38,840 --> 00:21:42,480 Speaker 2: add iodine to salts. Rather than trying some other strategy 338 00:21:42,640 --> 00:21:47,639 Speaker 2: to get iodine into people's diets. Various experiments involving iodine 339 00:21:47,720 --> 00:21:50,960 Speaker 2: supplements in the late nineteenth and early twentieth century hadn't 340 00:21:51,000 --> 00:21:54,760 Speaker 2: been really successful, Like there were iodine syrups that tasted 341 00:21:54,800 --> 00:21:58,600 Speaker 2: disgusting so children didn't want to take them, or these 342 00:21:58,600 --> 00:22:01,720 Speaker 2: were supplements that only needed to be administered every few months, 343 00:22:02,119 --> 00:22:05,639 Speaker 2: so people would just forget about them. Meanwhile, salt was 344 00:22:05,640 --> 00:22:09,360 Speaker 2: something that virtually everyone used in cooking, and its use 345 00:22:09,400 --> 00:22:13,240 Speaker 2: didn't really vary much from season to season, unlike in 346 00:22:13,359 --> 00:22:16,639 Speaker 2: earlier eras where the salt trade could involve long and 347 00:22:16,840 --> 00:22:19,720 Speaker 2: arduous journeys, which I mean, I guess it still could 348 00:22:19,720 --> 00:22:22,960 Speaker 2: in the early twentieth century, but most people had access 349 00:22:22,960 --> 00:22:25,879 Speaker 2: to salt at a local store at a reasonable price, 350 00:22:26,560 --> 00:22:29,360 Speaker 2: and unlike today, there wasn't a big public health focus 351 00:22:29,440 --> 00:22:33,560 Speaker 2: on reducing salt intake due to sodium's connection to high 352 00:22:33,560 --> 00:22:37,400 Speaker 2: blood pressure. Salt wasn't the only thing that people tried 353 00:22:37,440 --> 00:22:41,400 Speaker 2: adding iodine to in the US, though. In Rochester, New York, 354 00:22:41,440 --> 00:22:43,600 Speaker 2: there was a plan to add ionine to the drinking 355 00:22:43,680 --> 00:22:48,119 Speaker 2: water that started on April twenty fourth, nineteen twenty three. 356 00:22:48,160 --> 00:22:51,320 Speaker 2: This involved adding sodium iodide to the inflow of the 357 00:22:51,320 --> 00:22:55,320 Speaker 2: city's reservoir in a project overseen by doctor George W. Goehler, 358 00:22:55,640 --> 00:22:59,679 Speaker 2: who was Rochester's health officer. He had his own backstory 359 00:22:59,680 --> 00:23:04,560 Speaker 2: that we not getting into, including apparently opposing pasteurization because 360 00:23:04,560 --> 00:23:07,439 Speaker 2: he had seen such a reduction in milk boorn illnesses 361 00:23:07,480 --> 00:23:11,840 Speaker 2: through his own inspection program. This effort to add iodine 362 00:23:11,840 --> 00:23:14,720 Speaker 2: to the water was relatively effective, but it had some 363 00:23:14,880 --> 00:23:18,480 Speaker 2: challenges like the amount of iodine that could be added 364 00:23:18,520 --> 00:23:21,320 Speaker 2: to the reservoir was not enough to keep the average 365 00:23:21,400 --> 00:23:26,000 Speaker 2: person's thyroid working well, at least not if they drank 366 00:23:26,040 --> 00:23:29,600 Speaker 2: a typical amount of water, so people were advised to 367 00:23:29,680 --> 00:23:33,400 Speaker 2: drink more tap water, as much as three times more 368 00:23:33,560 --> 00:23:37,000 Speaker 2: than they were typically drinking. The level of iodine in 369 00:23:37,040 --> 00:23:40,320 Speaker 2: the tap water also dropped really quickly after it was 370 00:23:40,359 --> 00:23:41,400 Speaker 2: added to the reservoir. 371 00:23:42,280 --> 00:23:44,879 Speaker 1: A lot of people also objected to the idea of 372 00:23:44,920 --> 00:23:49,200 Speaker 1: something being added to their drinking water, including other water authorities. 373 00:23:49,800 --> 00:23:52,200 Speaker 1: For example, a write up by the British Water Works 374 00:23:52,200 --> 00:23:55,920 Speaker 1: Association set in part quote, it is contrary to ordinary 375 00:23:56,000 --> 00:23:59,760 Speaker 1: medical teaching to force a whole population to drink doped 376 00:23:59,800 --> 00:24:03,480 Speaker 1: water to the benefit of the minority. There were also 377 00:24:03,520 --> 00:24:06,639 Speaker 1: several fires that appeared to be arson and threats that 378 00:24:06,640 --> 00:24:09,760 Speaker 1: there would be more fires if this program was not stopped. 379 00:24:10,520 --> 00:24:13,640 Speaker 1: Although the rate of goiter in and around Rochester did 380 00:24:13,680 --> 00:24:16,840 Speaker 1: decline while this program was going on, it ended during 381 00:24:16,880 --> 00:24:20,000 Speaker 1: the Great Depression, after a round of budget cuts and 382 00:24:20,080 --> 00:24:24,480 Speaker 1: Goaler's retirement to return to Michigan. There was a proposal 383 00:24:24,520 --> 00:24:28,240 Speaker 1: to pass a state law mandating the addition of iodine 384 00:24:28,280 --> 00:24:31,800 Speaker 1: to salt, but there were a number of worries, in 385 00:24:31,840 --> 00:24:35,800 Speaker 1: my opinion, well founded worries that people would object to 386 00:24:35,920 --> 00:24:39,199 Speaker 1: a legal mandate that required something to be added to 387 00:24:39,240 --> 00:24:43,199 Speaker 1: their food. So instead, health authorities in Michigan started a 388 00:24:43,240 --> 00:24:47,840 Speaker 1: campaign of public education and a sort of industry pr 389 00:24:47,960 --> 00:24:51,640 Speaker 1: campaign similar to what had happened in Switzerland, to convince 390 00:24:51,680 --> 00:24:55,280 Speaker 1: all of the cantons to sell idise salt. This involved 391 00:24:55,280 --> 00:24:58,880 Speaker 1: almost two hundred public health lectures that were carried out 392 00:24:58,920 --> 00:25:02,000 Speaker 1: all over the state and work with the Michigan Salt 393 00:25:02,000 --> 00:25:05,959 Speaker 1: Producers Association and outreach to the presidents of all the 394 00:25:06,000 --> 00:25:10,040 Speaker 1: individual salt producers that were selling their products in Michigan. 395 00:25:10,600 --> 00:25:12,600 Speaker 1: These folks were nicknamed the Saltmen. 396 00:25:13,880 --> 00:25:14,840 Speaker 3: This became a. 397 00:25:14,840 --> 00:25:18,639 Speaker 1: Huge cooperative effort between Michigan's public health workers and the 398 00:25:18,680 --> 00:25:22,720 Speaker 1: salt industry, with David Marie Cowie being a major presence 399 00:25:22,800 --> 00:25:25,760 Speaker 1: in all of it. Officials had to convince the salt 400 00:25:25,800 --> 00:25:29,400 Speaker 1: industry that adding iodine wouldn't affect the quality of their product. 401 00:25:29,760 --> 00:25:32,640 Speaker 1: They even brought in William Hale of Dow Chemical Company 402 00:25:32,880 --> 00:25:35,719 Speaker 1: to demonstrate that it would not change the salt's flavor 403 00:25:35,840 --> 00:25:38,840 Speaker 1: or function. They worked at a process for adding the 404 00:25:38,880 --> 00:25:42,560 Speaker 1: iodine at a step into process when magnesia was already 405 00:25:42,600 --> 00:25:45,439 Speaker 1: being added to keep the salt free flowing, and that 406 00:25:45,480 --> 00:25:48,800 Speaker 1: cut down on the costs involved. They also had to 407 00:25:48,840 --> 00:25:51,760 Speaker 1: do some outreach within the medical community to try to 408 00:25:51,800 --> 00:25:56,199 Speaker 1: reassure doctors that adding iodine to the salt would not 409 00:25:56,400 --> 00:25:59,960 Speaker 1: just flip the situation and cause an epidemic of hype 410 00:26:00,280 --> 00:26:06,199 Speaker 1: thyroidism instead of hypothyroidism. That bit is a little more complicated. 411 00:26:06,840 --> 00:26:09,479 Speaker 1: The amount of iodine that was to be added to 412 00:26:09,520 --> 00:26:13,120 Speaker 1: the salt was nowhere near enough to cause hyper thyroidism 413 00:26:13,160 --> 00:26:17,679 Speaker 1: in somebody whose thyroid was actually working properly, but it 414 00:26:17,960 --> 00:26:20,800 Speaker 1: was enough to cause problems in people who were already 415 00:26:20,880 --> 00:26:25,879 Speaker 1: experiencing serious thyroid dysfunction. According to a paper published in 416 00:26:25,880 --> 00:26:29,440 Speaker 1: the Journal of the European Economic Association in twenty seventeen. 417 00:26:30,000 --> 00:26:33,760 Speaker 1: Iodization may have contributed to as many as ten thousand 418 00:26:33,880 --> 00:26:36,600 Speaker 1: deaths in the United States between nineteen twenty five and 419 00:26:36,680 --> 00:26:41,360 Speaker 1: nineteen forty two, primarily among people who had been chronically 420 00:26:41,480 --> 00:26:45,120 Speaker 1: iodine deficient for a very long time like many years. 421 00:26:45,960 --> 00:26:49,000 Speaker 1: Officials in Michigan also wanted to be able to clearly 422 00:26:49,119 --> 00:26:52,360 Speaker 1: document whether this whole effort was working, so they set 423 00:26:52,400 --> 00:26:56,359 Speaker 1: up a research program to evaluate the effects of iodized salt. 424 00:26:57,240 --> 00:26:59,879 Speaker 1: This started with a baseline survey of the rates of 425 00:27:00,040 --> 00:27:04,160 Speaker 1: guaiter and other thyroid issues before iodized salt became available 426 00:27:04,200 --> 00:27:07,640 Speaker 1: in stores, with follow ups to see how things changed 427 00:27:07,720 --> 00:27:11,159 Speaker 1: after people had access to iodized salt. A lot of 428 00:27:11,160 --> 00:27:13,840 Speaker 1: this was happening in late nineteen twenty three, and on 429 00:27:13,880 --> 00:27:17,920 Speaker 1: March fifteenth, nineteen twenty four, the Michigan State Medical Society 430 00:27:18,040 --> 00:27:21,760 Speaker 1: publicly endorsed the use of salt that contained zero point 431 00:27:21,880 --> 00:27:26,760 Speaker 1: zero one percent sodium iodide. Six different companies selling salt 432 00:27:26,840 --> 00:27:30,400 Speaker 1: in Michigan had their iodized products ready to go that May. 433 00:27:31,240 --> 00:27:34,760 Speaker 1: Morton was something of a latecomer. There were executives who 434 00:27:34,840 --> 00:27:38,840 Speaker 1: had concerns about producing iodized salt for only a couple 435 00:27:38,840 --> 00:27:41,800 Speaker 1: of states if that salt was not also being used 436 00:27:41,840 --> 00:27:43,400 Speaker 1: in all of the other states. 437 00:27:44,280 --> 00:27:48,080 Speaker 2: Morton started selling iodized salt a few months after everyone else, 438 00:27:48,200 --> 00:27:51,000 Speaker 2: and by the fall of that year, iodized salt was 439 00:27:51,040 --> 00:27:55,159 Speaker 2: available in stores all across the United States. In most 440 00:27:55,200 --> 00:27:59,200 Speaker 2: places in the US, iodized and non iodized salt were 441 00:27:59,240 --> 00:28:03,280 Speaker 2: both sold into stores, but thanks to extensive public education 442 00:28:03,440 --> 00:28:06,680 Speaker 2: campaigns and advertising on the part of the salt companies, 443 00:28:07,280 --> 00:28:10,480 Speaker 2: most people who had access to iodized salt bought it. 444 00:28:11,320 --> 00:28:14,520 Speaker 2: Follow Up studies in Michigan showed that once iodized salt 445 00:28:14,600 --> 00:28:18,760 Speaker 2: was widely available, incidents of enlarged thyroids dropped by up 446 00:28:18,760 --> 00:28:22,840 Speaker 2: to ninety percent. By nineteen thirty two, between ninety and 447 00:28:23,000 --> 00:28:26,440 Speaker 2: ninety five percent of salt sold in Michigan was iodized, 448 00:28:27,080 --> 00:28:29,879 Speaker 2: so by the mid nineteen twenties, it was clear that 449 00:28:30,000 --> 00:28:33,520 Speaker 2: iodine had an effect on the prevalence of goiter and 450 00:28:33,640 --> 00:28:37,439 Speaker 2: on hypothyroidism, and that salt was an effective way to 451 00:28:37,520 --> 00:28:41,600 Speaker 2: get enough iodine into people's diets, but people still didn't 452 00:28:41,600 --> 00:28:45,720 Speaker 2: fully understand why this worked, including within the medical community. 453 00:28:46,360 --> 00:28:49,560 Speaker 2: An international conference on goiter was held and burned in 454 00:28:49,640 --> 00:28:53,240 Speaker 2: nineteen twenty seven, and causes for goiter that were proposed 455 00:28:53,240 --> 00:28:58,720 Speaker 2: at this conference included intestinal parasites, poor hygiene, bad food, 456 00:28:58,840 --> 00:29:03,240 Speaker 2: and contaminated drinking water. A lot of the experts cited 457 00:29:03,320 --> 00:29:06,840 Speaker 2: these as the cause of goiter. While agreeing that the 458 00:29:06,880 --> 00:29:10,600 Speaker 2: addition of iodine to the salt worked to treat that goiter, 459 00:29:11,640 --> 00:29:14,840 Speaker 2: they concluded, though, that the iodine was killing the parasites 460 00:29:15,000 --> 00:29:19,160 Speaker 2: or destroying whatever was contaminating the food or water. Even 461 00:29:19,200 --> 00:29:22,280 Speaker 2: in nineteen thirty three, an article in Public Health Reports 462 00:29:22,480 --> 00:29:26,920 Speaker 2: still characterized the cause of endemic goiter as the subject 463 00:29:26,960 --> 00:29:30,560 Speaker 2: of speculation and of divergence of opinion. 464 00:29:31,640 --> 00:29:35,680 Speaker 1: David Murray Cowie died on January twenty seventh, nineteen forty, 465 00:29:35,800 --> 00:29:39,600 Speaker 1: after a coronary thrombosis. At that point, he had been 466 00:29:39,640 --> 00:29:44,400 Speaker 1: working toward a national campaign for iodized salt. His replacement, 467 00:29:44,520 --> 00:29:48,440 Speaker 1: Frederick B. Minor, continued toward that goal and helped establish 468 00:29:48,520 --> 00:29:52,120 Speaker 1: an iodized Salt Committee at the American Public Health Association. 469 00:29:53,040 --> 00:29:57,520 Speaker 1: Although bills were introduced to mandate iodized salt nationwide, none 470 00:29:57,560 --> 00:29:58,600 Speaker 1: of them ever passed. 471 00:29:59,480 --> 00:30:05,120 Speaker 2: Today, laws and standards around iodized salt vary widely from 472 00:30:05,160 --> 00:30:09,000 Speaker 2: one country to another, but an estimated eighty eight percent 473 00:30:09,080 --> 00:30:12,800 Speaker 2: of people around the world have access to iodized salt. 474 00:30:13,400 --> 00:30:16,440 Speaker 2: For the most part, once a nation's salt iodization program 475 00:30:16,520 --> 00:30:20,240 Speaker 2: is well established, people typically still have access to iodized 476 00:30:20,280 --> 00:30:23,920 Speaker 2: salt even when war or some kind of other unrest 477 00:30:24,160 --> 00:30:28,840 Speaker 2: disrupts other public health measures like vaccine programs. But that 478 00:30:29,000 --> 00:30:31,719 Speaker 2: still means that around the world, more than nine hundred 479 00:30:31,720 --> 00:30:35,320 Speaker 2: million people don't have access to iodized salt, and an 480 00:30:35,440 --> 00:30:39,640 Speaker 2: estimated fifty million people have enlarged thyroid glands and possibly 481 00:30:39,720 --> 00:30:43,400 Speaker 2: other concerns. Because of this, researchers have also looked for 482 00:30:43,440 --> 00:30:47,160 Speaker 2: other ways to distribute iodine in places where iodized salt 483 00:30:47,280 --> 00:30:49,960 Speaker 2: isn't practical for some reason or where there's some other 484 00:30:50,040 --> 00:30:54,200 Speaker 2: issue going on. One example is the use of iodinated 485 00:30:54,320 --> 00:30:58,320 Speaker 2: poppyseed oil in highland areas of New Guinea where iodine 486 00:30:58,360 --> 00:31:03,920 Speaker 2: deficiency is particularly or adding iodine to irrigation water or 487 00:31:03,960 --> 00:31:08,280 Speaker 2: animal feeds so that it makes its way into other foods. Interestingly, 488 00:31:08,520 --> 00:31:11,480 Speaker 2: the twenty one nations that are currently reported as having 489 00:31:11,520 --> 00:31:15,320 Speaker 2: insufficient iodine intake are scattered all over the world in 490 00:31:15,360 --> 00:31:18,440 Speaker 2: a way that looks pretty random on a globe. This 491 00:31:18,520 --> 00:31:22,760 Speaker 2: includes both rich and poor countries. In Europe, Asia, Africa, 492 00:31:22,760 --> 00:31:26,800 Speaker 2: and Central America, and there are thirteen countries that have 493 00:31:27,000 --> 00:31:30,760 Speaker 2: too much iodine, either from already abundant iodine in their 494 00:31:30,800 --> 00:31:35,360 Speaker 2: diets or over iodization of the salt. Here in the 495 00:31:35,480 --> 00:31:39,480 Speaker 2: United States, dietary iodine intake has been declining since the 496 00:31:39,560 --> 00:31:43,360 Speaker 2: nineteen seventies. Some of this is because of concerns about 497 00:31:43,400 --> 00:31:48,240 Speaker 2: the connection between sodium intake and hypertension, although the biggest 498 00:31:48,320 --> 00:31:52,240 Speaker 2: sources of sodium in the typical American diet are processed 499 00:31:52,280 --> 00:31:56,080 Speaker 2: foods that are not usually made with iodized salt, not 500 00:31:56,320 --> 00:32:00,680 Speaker 2: the iodized table salt that people might be avoiding. But 501 00:32:00,800 --> 00:32:04,440 Speaker 2: another reason is just an increasing preference for things like 502 00:32:04,560 --> 00:32:09,000 Speaker 2: sea salt and kosher salt and Himalayan pink salt. These 503 00:32:09,000 --> 00:32:12,520 Speaker 2: are typically not iodized, although there are some brands that 504 00:32:12,640 --> 00:32:15,400 Speaker 2: do carry iodized versions of these products. 505 00:32:16,160 --> 00:32:18,360 Speaker 1: At this point, a lot of people in the US 506 00:32:18,400 --> 00:32:21,200 Speaker 1: are getting more of their iodine from dairy products than 507 00:32:21,240 --> 00:32:24,720 Speaker 1: from table salt, which means the rising preference for non 508 00:32:24,800 --> 00:32:27,600 Speaker 1: dairy milks is playing a part in this story as well. 509 00:32:28,240 --> 00:32:31,560 Speaker 1: Whether a plant based milk contains iodine depends on what 510 00:32:31,680 --> 00:32:34,600 Speaker 1: it is made of. Some of them use thickeners made 511 00:32:34,600 --> 00:32:38,040 Speaker 1: from seaweed, although the iodine and the seaweed might not 512 00:32:38,120 --> 00:32:40,360 Speaker 1: make it through the manufacturing process. 513 00:32:40,760 --> 00:32:44,800 Speaker 2: In the United States, nutrition labels typically only list iodine 514 00:32:44,840 --> 00:32:48,120 Speaker 2: content if that was added into the product, not if 515 00:32:48,120 --> 00:32:51,040 Speaker 2: the iodine occurs naturally, and that can make it tricky 516 00:32:51,120 --> 00:32:54,080 Speaker 2: to know how much iodine a person is actually getting, 517 00:32:54,720 --> 00:32:57,080 Speaker 2: and this affects people who are trying to get enough 518 00:32:57,120 --> 00:33:00,760 Speaker 2: iodine as well as people who need to avoid iodine. 519 00:33:01,440 --> 00:33:05,080 Speaker 2: For example, people who are getting radioactive iodine treatment are 520 00:33:05,120 --> 00:33:09,520 Speaker 2: typically advised to avoid iodine in their diets. Since we 521 00:33:09,600 --> 00:33:13,200 Speaker 2: have a whole episode on the history of radio iodine treatment, 522 00:33:13,360 --> 00:33:15,800 Speaker 2: we're gonna run that as a Saturday Classic because it 523 00:33:15,840 --> 00:33:16,680 Speaker 2: overlaps with this. 524 00:33:16,720 --> 00:33:20,400 Speaker 1: A little bit. Do you also have listener mail for us? 525 00:33:20,480 --> 00:33:23,720 Speaker 1: I do have listener mail for us. It is from Jody. 526 00:33:24,560 --> 00:33:28,120 Speaker 1: Jody wrote, Hi, Holly and Tracy. Usually I listened to 527 00:33:28,160 --> 00:33:31,040 Speaker 1: your podcast weekday mornings when getting ready for work, but 528 00:33:31,080 --> 00:33:34,560 Speaker 1: when I saw this week's lineup was food themed, I 529 00:33:34,640 --> 00:33:38,280 Speaker 1: decided to spend my Saturday afternoon with you. What caught 530 00:33:38,320 --> 00:33:41,720 Speaker 1: my eye was banana ketchup. This came on my radar 531 00:33:41,800 --> 00:33:44,120 Speaker 1: a few years ago after I moved from the Florida 532 00:33:44,200 --> 00:33:47,040 Speaker 1: Keys to Las Vegas, Nevada, where there's a much larger 533 00:33:47,080 --> 00:33:51,440 Speaker 1: Filipino population. I'm also a canner and had to figure 534 00:33:51,480 --> 00:33:54,640 Speaker 1: out what to do with the fifteen ish pounds of 535 00:33:54,760 --> 00:33:58,160 Speaker 1: bananas that showed up with an Instacart order instead of 536 00:33:58,200 --> 00:34:02,600 Speaker 1: the one bunch I was exp This was during the pandemic, 537 00:34:02,680 --> 00:34:06,760 Speaker 1: so another quick sweetbread was out of the question. I 538 00:34:06,840 --> 00:34:10,120 Speaker 1: look forward to reading more about Maria Rosa's story using 539 00:34:10,160 --> 00:34:12,960 Speaker 1: your references as a guide. As for how my banana 540 00:34:13,040 --> 00:34:15,640 Speaker 1: ketchup turned out, it was interesting. 541 00:34:15,920 --> 00:34:16,320 Speaker 3: Lol. 542 00:34:16,400 --> 00:34:19,560 Speaker 2: Here's the safe canning recipe I used. There's a link 543 00:34:19,600 --> 00:34:23,440 Speaker 2: to a recipe for banana ketchup. A Filipino co worker 544 00:34:23,560 --> 00:34:26,640 Speaker 2: tasted it and approved, but my brain had trouble making 545 00:34:26,719 --> 00:34:29,600 Speaker 2: sense of the color and I couldn't eat it with fries. 546 00:34:29,680 --> 00:34:33,200 Speaker 2: But I do make a beat ketchup that gets gobbled up, 547 00:34:33,280 --> 00:34:36,280 Speaker 2: so I know that's just in my head. That being said, 548 00:34:36,320 --> 00:34:39,239 Speaker 2: I do try to run a zero waste kitchen, so 549 00:34:39,280 --> 00:34:41,600 Speaker 2: I use it as a base for barbecue sauce for 550 00:34:41,680 --> 00:34:44,399 Speaker 2: grilled ribs, and my guests kept trying to figure out 551 00:34:44,400 --> 00:34:48,360 Speaker 2: what the secret flavor was while licking their fingers attached 552 00:34:48,360 --> 00:34:50,600 Speaker 2: for cat tacks are picks of our ten year old 553 00:34:50,680 --> 00:34:55,040 Speaker 2: spicy cat Ella and almost four year old goofball Jazzber. 554 00:34:55,520 --> 00:34:58,120 Speaker 2: My husband is a jazz musician, so Ella is named 555 00:34:58,160 --> 00:35:01,560 Speaker 2: after Ella Fitzgerald, and Jazz has not stopped purring since 556 00:35:01,560 --> 00:35:04,120 Speaker 2: we adopted him from a shelter. His eyes looked like 557 00:35:04,280 --> 00:35:12,480 Speaker 2: green jasper. This cat's I like this. I'm looking at 558 00:35:12,480 --> 00:35:16,560 Speaker 2: a picture of a black cat with a very startled expression. 559 00:35:18,640 --> 00:35:22,920 Speaker 2: I don't know if this kitty cat is actually startled, 560 00:35:23,800 --> 00:35:25,719 Speaker 2: but that's that's the way that it struck me. And 561 00:35:25,760 --> 00:35:29,000 Speaker 2: then there's also other kitty cat, so I'm guessing this 562 00:35:29,040 --> 00:35:29,600 Speaker 2: one is Ella. 563 00:35:29,680 --> 00:35:31,880 Speaker 3: Ella is on a bookshelf. 564 00:35:32,760 --> 00:35:35,640 Speaker 2: Posed in such a way that at first I thought 565 00:35:35,800 --> 00:35:38,040 Speaker 2: this was like a cat figurine. 566 00:35:38,719 --> 00:35:41,879 Speaker 3: No, it is the real cat on the bookshelf. Thank 567 00:35:41,920 --> 00:35:42,319 Speaker 3: you so much. 568 00:35:42,400 --> 00:35:47,319 Speaker 2: I'm so interested about number one hearing the that you know, 569 00:35:47,600 --> 00:35:50,359 Speaker 2: somebody just needed to make some banana ketchup at home 570 00:35:50,400 --> 00:35:52,279 Speaker 2: because of all of these extra bananas. And then it 571 00:35:52,280 --> 00:35:56,360 Speaker 2: also reminded me of experience I had in the early 572 00:35:56,560 --> 00:36:02,000 Speaker 2: pandemic years when I had an order from like a 573 00:36:02,040 --> 00:36:07,600 Speaker 2: place that sold locally grown fruits and vegetables and things, 574 00:36:07,800 --> 00:36:12,440 Speaker 2: and the it was described as a pound of halapeno peppers, 575 00:36:12,440 --> 00:36:14,919 Speaker 2: and I was like, I don't think that can be right, 576 00:36:15,200 --> 00:36:17,480 Speaker 2: don't I don't think I'm gonna get a whole pound 577 00:36:17,520 --> 00:36:22,040 Speaker 2: of halapeno peppers. I did, so I made a bunch 578 00:36:22,120 --> 00:36:25,520 Speaker 2: of infused vodka with because that was more holopenos than 579 00:36:25,600 --> 00:36:29,120 Speaker 2: I needed at that moment. Uh So, thank you so 580 00:36:29,239 --> 00:36:32,319 Speaker 2: much for that email. If you would like to send 581 00:36:32,360 --> 00:36:34,560 Speaker 2: us a note about this or any other episode, where 582 00:36:34,560 --> 00:36:38,759 Speaker 2: at History Podcasts at iHeartRadio dot com, and you can 583 00:36:38,800 --> 00:36:43,240 Speaker 2: subscribe to the show on the iHeartRadio app and anywhere 584 00:36:43,239 --> 00:36:51,000 Speaker 2: else you'd like to get your podcasts. Stuff you Missed 585 00:36:51,000 --> 00:36:54,160 Speaker 2: in History Class is a production of iHeartRadio. For more 586 00:36:54,200 --> 00:36:58,600 Speaker 2: podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or 587 00:36:58,600 --> 00:37:00,839 Speaker 2: wherever you listen to your favor shows.