The Salt Trend That Could Cost Children Up to 13 IQ Points

It sounds like clickbait, but it isn’t.

Research suggests that mild to moderate iodine deficiency during pregnancy is associated with reductions in children’s IQ ranging from around 0.3 to as much as 13 points across different studies (Bougma et al., 2013). More importantly for the UK, children born to mothers with iodine deficiency were significantly more likely to have lower verbal IQ and poorer reading ability in the landmark ALSPAC study (Bath et al., 2013). (BMJ)

A century ago, adding iodine to table salt virtually eliminated iodine deficiency in many countries. It reduced goitre, improved thyroid health and is widely regarded as one of the greatest public health interventions ever introduced.

Unfortunately, iodine deficiency is now returning.

A 2026 review by Professor Sarah Bath reports that data from the UK National Diet and Nutrition Survey (2019–2023) now classifies several population groups—including women of childbearing age—as mildly iodine deficient. The review concludes that iodine deficiency has become “a significant public health concern in the UK” and warns that deficiency before and during pregnancy may affect children’s cognition, including IQ. (PubMed)

Why?

• Sea salt, Himalayan pink salt and many gourmet salts do not contain added iodine.
• More people are replacing cow’s milk with plant-based alternatives, many of which contain little iodine unless fortified.
• The UK has never introduced universal salt iodisation, unlike many other countries, and iodised salt is still not widely available. (PubMed)

For those of us working in early years, this matters.

The foundations of brain development begin long before a child enters nursery. While we should never encourage people to consume more salt, we can help families understand the importance of getting enough iodine from appropriate sources, including dairy products, seafood, eggs, iodised salt (used sparingly), or appropriately fortified foods.

Sometimes the biggest threats to children’s development aren’t obvious. Sometimes they’re hidden in changing dietary trends that most of us never question.

References

Bath SC. (2026). Iodine deficiency in the UK – should we take it with a pinch of salt? Proceedings of the Nutrition Society. PMID: 41501008. (PubMed)

Bath SC, Steer CD, Golding J, Emmett P, Rayman MP. (2013). Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). The Lancet, 382(9889), 331–337. (BMJ)

Bougma K, Aboud FE, Harding KB, Marquis GS. (2013). Iodine and mental development of children under 5 years: A systematic review and meta-analysis. Nutrition, 29(9), 1089–1098.

This version is stronger because it uses the 2026 review by Sarah Bath to establish that iodine deficiency is once again a UK public health issue, while the 2013 ALSPAC study and 2013 meta-analysis support the cognitive findings. Together, they make a robust evidence base.