Full Transcript Iodine Deficiency and Seaweed Origins 0:01 "The Best Source of Iodine to Avoid Deficiency" 0:06 Iodine was first discovered in seaweed in the 1800s, 0:10 but 3,000 years earlier 0:12 the Chinese were using seaweed to treat goiter, 0:14 the swelling of the thyroid gland 0:16 in the front of the neck caused by iodine deficiency. 0:20 There is iodine in land plants, 0:22 but how much depends on the iodine content 0:24 of the soil, 0:25 resulting in a hundred-fold difference 0:27 in iodine content depending where the crop is grown. 0:30 In the United States, there was the goiter belt, 0:33 a large swath of the country with iodine-deficient soils, 0:36 which was only relieved 0:37 when iodine started to be added to salt in the 1920s. 0:42 Of course, we shouldn't be eating salt,
Salt, Dairy, and Plant Milk Iodine Sources 0:44 to help prevent diseases like high blood pressure, 0:46 but if you do use salt, use iodized salt, 0:48 not sea salt, not kosher salt, 0:50 not rainbow-colored Himalayan salt. 0:53 It should explicitly say iodized on the packaging. 0:57 And the salt added to processed foods 0:58 almost never contains it. 1:00 But again, we shouldn't use salt at all, 1:02 so what foods have it naturally? 1:04 In the United States, 1:05 the leading source by far is dairy. 1:09 That's the case in many countries, 1:10 though ironically, cow's milk doesn't naturally have 1:13 much iodine, but can become a rich source 1:16 if the cows are fed iodine 1:18 or iodine-containing disinfectants are used 1:21 during the milking process; 1:22 in other words, cross-contamination 1:24 through the use of iodine for the disinfection of the teats. 1:27 The practice of teat disinfection 1:29 with iodine solution 1:30 has been identified as a factor 1:31 that increases the concentration 1:33 of iodine in milk, 1:34 both by direct contamination 1:37 and by absorption by the epithelium (the skin) 1:40 on the cow's teats, 1:42 which are either dipped into the iodine solution, 1:44 or it's sprayed on 1:45 and kind of leaches into the milk. 1:47 Now this leads to a large variability of iodine content 1:50 in retail milk, 1:51 anywhere from about 30 to 250 micrograms a cup, 1:54 with an average of 86, 1:56 more than half the recommended dietary allowance 1:58 of 150 a day. 2:00 Yes, variable, but check out the iodine 2:03 in plant-based milks in the U.S. grocery stores. 2:07 They aren't fortified, there are no almond teats, 2:11 so they average only 3 micrograms. 2:13 You'd have to drink 50 cups a day! 2:15 Why don't plant-based milk companies 2:17 fortify their milks with iodine? 2:19 Good question. 2:20 And we see the same problem in other countries. 2:23 Okay, so what do we do? 2:24 We don't want to eat salt,
Sea Vegetables as the Best Low-Salt Source 2:26 as it's the number one dietary risk factor 2:28 for death on planet Earth. 2:31 Dairy may be the number one source of iodine 2:33 in the American diet, 2:34 but it's also the number one source 2:36 of cholesterol-raising saturated fat. 2:39 Iodine is also fed to egg-laying hens, 2:41 but eggs are the number one source 2:44 of dietary cholesterol by far, 2:46 the intake of which should be as low as possible. 2:49 That leaves foods from the oceans, 2:51 both plant and animal, 2:53 but after looking at the evidence 2:54 for contaminants in fish, shrimp, and other seafood, 2:58 we're pretty much left with the bottom 3:00 of the aquatic food chain with sea vegetables. 3:04 The good news is that sea veggies 3:05 are so high in iodine that even tiny doses a day 3:09 can get us all the iodine we need, 3:11 like one sheet of nori a day, 3:13 or a half teaspoon of dulse flakes. 3:15 Don't overdo it, though. 3:17 Kombu, which is a type of kelp, has so much iodine 3:20 that even just an eighth of a teaspoon a day 3:22 could put us well over the tolerable upper limit 3:25 of daily intake. 3:27 But if we aren't eating salt, or dairy, or fish, or seaweed, 3:30 we may be at risk 3:31 of having inadequate iodine intake. 3:34 The most common way to test for average iodine intake 3:37 in a population is to measure the amount in their urine,
Testing Iodine Status and Vegan Intake 3:40 since we pee out more than 90% of it. 3:43 Since that changes on a day-to-day basis, though, 3:45 it isn't really a good test 3:47 for an individual's iodine status. 3:49 Like, if you happened to have a bite of seaweed salad 3:51 at lunch the day of the test, that could throw it off, 3:54 but, on average, you can get a sense. 3:57 Here are the cut-offs for the test, 3:58 where under 20 could mean severe iodine deficiency, 4:01 under 50, moderate deficiency, 4:03 and over a hundred is considered normal. 4:06 In this study from Norway, 4:07 another place where few plant-based milks 4:09 are iodine enriched, 4:10 vegans came in at 43, 4:12 vegetarians at 67, 4:14 and fish eaters at 96. 4:16 Now this did not appear to manifest 4:19 as impaired thyroid function, 4:21 which is what would happen 4:22 if you were really iodine deficient. 4:24 Similarly in Sweden and in Finland- 4:26 normal thyroid function. 4:28 The same with vegans in the United States. 4:30 If anything, they had lower risk of an underactive thyroid. 4:33 Although a low iodine intake may not have an acute effect 4:37 on thyroid function, 4:38 it's possible over time it may increase the risk 4:40 of thyroid disorders, 4:41 thus individuals with low iodine intakes 4:44 are recommended to consume dietary iodine supplements 4:47 or consume iodine-rich plant foods like seaweed. 4:51 In fact, seaweed has so much iodine 4:53 that it offgasses iodine into the air 4:56 such that if you live by the beach, 4:58 you can get iodine just breathing the air, 5:00 bringing new meaning to the expression, 5:02 "Sea air is good for you!" 5:05 Inadequate maternal iodine intake during pregnancy, 5:08 however, can be extremely serious. 5:12 There doesn't appear to be a significant difference
Pregnancy, Supplementation, and Deficiency Cases 5:14 in iodine content in breast milk among the diet groups, 5:17 but that's not saying much 5:18 since the estimated prevalence of inadequate iodine intake 5:21 for pregnant women across the board may be 23%. 5:25 The American Thyroid Association, 5:26 the Endocrine Society, 5:27 and the American Academy of Pediatrics all recommend 5:30 that all pregnant and lactating women 5:33 receive a daily supplement 5:34 containing 150 micrograms of iodine, 5:37 although only about 15% of lactating women 5:41 in the United States adhere to this recommendation. 5:44 Given potentially restricted iodine intake of vegans, 5:48 this recommendation is especially important 5:50 for vegan women of childbearing age. 5:54 Take, for example, this case report. 5:56 A 23-month-old boy diagnosed 5:58 with iodine deficiency hypothyroidism. 6:01 He was breastfed until 16 months of age, 6:03 getting iodine from his prenatal vitamin-taking mom, 6:07 but after weaning, the kid ate no fish, eggs, 6:10 meat, cow's milk, or iodized salt, which is great, 6:14 but there has to be a good alternative source of iodine. 6:17 Or this case. 6:18 This is what a goiter looks like. 6:20 A 6-year-old vegan girl 6:22 in a family who used non-iodized salt. 6:25 That is why consideration should be given 6:27 to iodine fortification of foods 6:28 commonly consumed by vegans, 6:30 including plant-based milks. 6:33 * END * 6:34 * END * 6:36 ♪ 6:38 (soft splashing, bubbling)
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