Iodine inadequacy has roughly doubled in the US since the early 2000s, raising concerns about thyroid health and brain development as fewer people consume iodised salt.
Americans are consuming less iodine than they once did, and that trend could carry real consequences for children’s development. Science News, citing recent research, reported that iodine inadequacy roughly doubled between 2001-02 and 2017-18, with nearly a quarter of women and almost a third of men aged 14 and older failing to get enough, while close to half of pregnant women fell short. The issue matters because iodine is needed to produce thyroid hormones, which are crucial for brain development before birth and in early childhood.
Public health officials have long known what happens when iodine is scarce. The CDC has said iodine deficiency disorders were largely eliminated in the United States after salt was fortified, but its data also point to a renewed rise in low urinary iodine levels in more recent surveys, reflecting shifts in food production and eating habits. Historical studies note that iodized salt first reached Michigan in 1924, and a later review found that it quickly helped reduce goitre, the visible swelling of the thyroid that once affected large numbers of schoolchildren in parts of the state.
That success, however, is no guarantee of lasting protection. A 2015 study found that only about 53% of salt products sold in the United States were iodized, and much of the salt Americans consume now comes through processed foods that typically use non-iodised salt. Endocrinologists quoted by Science News warned that iodised salt remains important but may no longer reach enough people to keep iodine intake at healthy levels, especially as shoppers increasingly choose speciality salts such as Himalayan, kosher and sea salt.
The concern is sharpest for women who are pregnant, breastfeeding or trying to conceive. The CDC’s 2026 Nutrition Report and the American Thyroid Association say women of reproductive age are close to mild deficiency, while the American Academy of Pediatrics recommends a daily 150-microgram iodine supplement for those in those groups. Research has also shown that the benefits of iodisation extend beyond thyroid health: a study in the Journal of the European Economic Association found that men born in iodine-poor regions later performed better on a World War II Air Force qualifying exam after iodised salt became available, underlining how a simple public health intervention can shape outcomes for years.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
