Speaker 1: Welcome to Brainstuff from house Stuff works dot com where
Speaker 1: smart happens Him Marshall Brain with today's question, why do
Speaker 1: they add iodine to table salt? I have a box
Speaker 1: of salt in the kitchen and it says iodide salt,
Speaker 1: and then at the bottom it says this salt supplies
Speaker 1: iodine and necessary nutrient on the ingredient label at lists
Speaker 1: potassium iodine at a concentration of zero point zero zero six.
Speaker 1: A quarter teaspoon of salt or one point five grams
Speaker 1: therefore provides sixty seven micrograms of iodine, which is about
Speaker 1: half of the US recommended daily allowance for iodine. The
Speaker 1: main reason that you need iodine is because of a
Speaker 1: gland in your neck called the thyroid gland. The thyroid
Speaker 1: gland produces two hormones, thyroxine and try iodo thyroneine that
Speaker 1: your body uses during metabolism. Without these hormones, you start
Speaker 1: to feel tired, depressed, cold, weak, and so on. Iodine
Speaker 1: is an important element in these two hormones, so without iodine,
Speaker 1: your thyroid gland can't produce them. When start for iodine,
Speaker 1: the thyroid gland also swells up, and when it does
Speaker 1: it's called a goiter. Groiters can look pretty hideous. Your
Speaker 1: body doesn't need or contain very much iodine. You might
Speaker 1: have twenty or twenty five milligrams of iodine in your
Speaker 1: entire body right now. However, in some parts of the world,
Speaker 1: the soil contains no iodine at all, so plants contain
Speaker 1: no iodine, and therefore iodine deficiency is a big problem.
Speaker 1: In the US, one part of the country that lacks
Speaker 1: iodine is the Great Lakes region, So companies started adding
Speaker 1: iodine to salt in the nineteen twenties to eliminate goiter
Speaker 1: and thyroid problems. If you lived through the Cold War,
Speaker 1: you may have heard about the practice of taking iodine
Speaker 1: pills during the threat of a nuclear attack. When a
Speaker 1: nuclear bomb explodes, one substance it forms is radioactive iodine.
Speaker 1: If you eat, drink, or inhale, this isotope. Your thyroid
Speaker 1: gland will concentrate it, and this can lead to a
Speaker 1: thyroid damage or a cancer. By taking an iodine pill,
Speaker 1: you saturate your thyroid gland with iodine and prevent it
Speaker 1: from absorbing any of the radioactive iodine. Do you have
Speaker 1: any ideas or suggestions for this podcast. If so, please
Speaker 1: send me an email at podcast at how stuff works
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