Men from the lowest-iodine areas born in 1924 or later had an average IQ that was 15 points higher than their predecessors.

Evidence

How Adding Iodine to Salt Boosted Americans’ IQ (Discover Magazine)

Categorization

• corroborated: 2 independent passages support this claim
• XREF: connects to: Adding iodine to salt closed a 15-point IQ gap cheaply — Harriet A. Washington, A Terrible Thing to Waste, 18; Results are consistent with iodization raising IQ by 15 points in iodine-deficient areas and a nationwide average increase of ~3.5 IQ points. — The Cognitive Effects of Micronutrient Deficiency: Evidence from Salt Iodization in the United States; Americans gained up to 15 IQ points after iodized salt became mandatory in 1924. — Iodized salt made Americans smarter: Study (+8 more)

Related

• Americans gained up to 15 IQ points after iodized salt became mandatory in 1924. (similarity 0.94)
• Results are consistent with iodization raising IQ by 15 points in iodine-deficient areas and a nationwide average increase of ~3.5 IQ points. (similarity 0.93)
• Introduction of iodized salt increased IQ by approximately 15 points for those most deficient in iodine. (similarity 0.92)
• A 2017 study found that the introduction of iodized salt in 1924 raised IQ for the one-quarter of the population most deficient in iodine. (similarity 0.92)
• Salt iodization raised IQ scores of millions of people by 15 IQ points in iodine-deficient regions and is highly cost-effective at pennies per person per year. (similarity 0.92)
• Salt iodization beginning in 1924 raised IQ by approximately one standard deviation (15 points) for the quarter of the population most deficient in iodine. (similarity 0.91)
• Iodine played a substantial role in cognitive improvements across the American population in the 20th century. (similarity 0.91)
• Iodized salt raised IQs by a full standard deviation (15 points) in iodine-deficient areas, and may explain a decade’s worth of the Flynn effect. (similarity 0.90)
• Adding iodine to salt in 1924 raised average U.S. IQ scores (similarity 0.90)
• We find that for the one quarter of the population most deficient in iodine this intervention raised IQ by approximately one standard deviation. (similarity 0.90)
• A 2013 study found a gradual increase in average intelligence of 1 standard deviation, 15 points in iodine-deficient areas and 3.5 points nationally after the introduction of iodised salt. (similarity 0.89)
• Adding iodine to salt beginning in 1924 increased IQ in America by as much as 15 points and boosted the U.S. economy. (similarity 0.89)
• The lower range of estimates is consistent with iodization raising IQ by 15 points, but also documents at least 10,000 excess deaths from iodine-induced hyperthyroidism. (similarity 0.88)
• Morton Salt began nationwide distribution of iodized salt in 1924, raising IQ in previously iodine-deficient areas and improving economic outcomes. (similarity 0.86)
• In low-iodine counties, the probability of assignment to the Air Forces rose significantly after the introduction of iodized salt. (similarity 0.86)

Library Connections

• Adding iodine to salt in 1924 raised average U.S. IQ scores #corroborates (0.90) — Did iodized salt raise the IQ of 50 million Americans by 15 points?
• Iodizing salt in 1924 closed a 15-point IQ gap cheaply #corroborates (0.85)