Iodine | Can Salt Make You Smart?
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A shocking revelation lies at the heart of this episode: iodine deficiency may be silently lowering IQs across the United States. The hosts dive into the science behind iodine, a trace mineral essential for thyroid function and brain development, especially in utero. They reveal that the widespread shift from iodized salt to kosher and sea salts—driven by culinary trends and health fads—has led to a dramatic drop in iodine intake. Data shows pregnant women’s iodine levels have halved since 1971, and researchers estimate this shift has contributed to a measurable decline in national IQ scores. The episode traces the history of iodized salt, from its adoption after World War I to its role in preventing goiters and cretinism, and reveals that the 15-point IQ increase seen between World War I and II enlistees was likely due to iodine fortification. Now, with dairy-based iodine sources declining and processed foods removing iodized salt, the U.S. is facing a quiet public health crisis—potentially reversing decades of cognitive gains. The hosts argue that simply switching back to iodized salt when cooking could be one of the easiest ways to boost national intelligence, and they deliver a bold, science-backed call to action: stop avoiding iodized salt, because it might just make you smarter.
Iodine deficiency during pregnancy is the leading preventable cause of intellectual disability, affecting fetal brain development.
The shift from iodized salt to kosher and sea salt over the past 20 years has caused a 50% drop in iodine levels among pregnant women.
Iodized salt was introduced in the 1920s to combat goiters and cretinism, and is linked to a 15-point average IQ increase between World War I and II enlistees.
The U.S. lacks mandatory iodine fortification laws—unlike most Western nations—making iodine intake a voluntary choice that’s increasingly being avoided.
Simply using iodized salt in cooking is enough to meet daily iodine needs and reverse deficiency without supplements.
…and 3 more takeaways available in PodZeus
The Iodine Paradox: A Poison That Makes You Smarter
The episode opens with a surreal mix of comedy, sponsor ads, and a personal health concern about numbness in the thigh. This leads to a deep dive into iodine, a mineral that is both toxic in excess and essential for life, especially brain development in utero.
Iodine's Role in the Body: From Thyroid to IQ
The hosts explain how iodine is critical for producing T3 and T4 hormones, which regulate metabolism, growth, and brain development. The thyroid gland’s inability to self-regulate when levels are too high is highlighted as a key vulnerability.
The Goiter Epidemic and the Birth of Iodized Salt
Historical context reveals how goiters—enlarged thyroids—were rampant in inland and northern regions due to iodine-poor soil. The U.S. military’s struggle to enlist men from Michigan due to goiters led to the 1920s iodization of salt, a public health breakthrough.
The IQ Revolution: How Salt Boosted National Intelligence
“Over the course of the 20th century, iodine, iodizing salt attributed to across the entire population, a 180 million point increase in IQ worldwide because of all these people who were all of a sudden ingesting more iodine in utero, which meant their brains were able to grow more.”
The Modern Crisis: Why We're Getting Dumber
“In 1971, the average iodine level for a pregnant woman was 327 micrograms a liter. Now, it's 144 micrograms a liter. So it's about cut in half.”
“of the 20th century, they estimate that iodine, iodizing salt attributed to across the entire population, a 180 million point increase in IQ worldwide because of all these people who were all of a sudden ingesting more iodine in utero, which meant their brains were able to grow more.”
“In 1971, the average iodine level for a pregnant woman was 327 micrograms a liter. Now, it's 144 micrograms a liter. So it's about cut in half.”
“Just cook with iodized salt. You don't need to go check it. Just get enough. Just eat. Whenever you use salt, use iodized salt and you're going to have enough and you're going to be fine.”
Hosts
iodine
other
thyroid gland
other
T3 and T4 hormones
other
Morton salt
brand
World War I
other
World War II
other
Rorschach test
other
Lean Cuisine
brand
1986 Ford F-150
other
Joseph Harvey Kellogg
person
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