The Element Iodine: Its Discovery, Health Benefits, and Why It’s in Salt

What It Covers

Iodine, discovered accidentally in 1811 Paris, is a halogen element requiring only 150 micrograms daily, yet its absence causes widespread intellectual disability, and its addition to table salt since 1922 has transformed global public health outcomes.

Key Questions Answered

• •Iodine deficiency geography: Mountainous inland regions — the Himalayas, Alps, Andes, and Great Lakes area — have iodine-depleted soils due to ancient glacial stripping. Populations there historically suffered endemic goiter and cognitive impairment, making geographic location a direct dietary iodine risk factor worth considering.
• •Thyroid hormone mechanics: The thyroid requires iodine to synthesize thyroxine and triiodothyronine — the numbers in their names literally count iodine atoms per molecule. These hormones regulate metabolism, heart rate, body temperature, and critically, fetal brain development during pregnancy, making deficiency especially damaging in pregnant women.
• •Salt iodization impact: Switzerland introduced national iodized salt in 1922, collapsing goiter rates within one generation. The U.S. followed in 1924. Today, 88% of the global population accesses iodized salt, making this one of history's most cost-effective public health interventions targeting the leading preventable cause of intellectual disability worldwide.
• •Specialty salt iodine gap: Sea salt, kosher salt, and artisanal salts sold widely in the U.S. contain no added iodine. As consumers shift away from standard table salt toward specialty varieties, nutritionists flag a measurable risk of declining iodine intake, particularly in populations already eating low seafood diets.