8 Studies Show Iodine Supplementation Improves Child Cognitive Function

Iodine supplementation slightly improves cognitive function in children and adolescents, according to a recent review.

While its impact on physical growth shows little to no difference in weight, the mineral serves a vital role in preventing severe developmental disorders in iodine-deficient populations.

Key Clinical Takeaways:

• Supplementation provides a slight increase in cognitive performance in at-risk pediatric populations.
• Clinical evidence indicates a likely large reduction in the incidence of hypothyroidism and a likely reduction in infant mortality.
• Current data remains inconclusive regarding the efficacy of iodine in reducing goitre, necessitating further, more rigorous trials.

Data from eight studies involving 2,528 participants conducted between 1982 and 2009 demonstrate that iodine supplementation has a positive effect on cognitive development. In one study of 166 individuals, those receiving iodine showed a slight increase in thinking ability compared to those receiving a placebo. Conversely, the evidence regarding physical growth is less compelling; three studies monitoring 658 children found little to no difference in weight between treated groups and control groups.

The physiological importance of iodine stems from its necessity in thyroid hormone production. In regions prone to deficiency, supplementation likely leads to a large reduction in hypothyroidism, as evidenced by a study of 264 people. In areas with high infant mortality rates, targeted iodine intervention is likely associated with a decrease in all-cause mortality, according to a study involving 617 participants.

Initial analysis of two studies involving 432 people yielded very uncertain results. When researchers excluded a study that did not use rigorous methods, the remaining data from 230 participants indicated a likely large reduction in goitre occurrence.

The quality of current evidence ranges from high to very low, influenced by variations in study populations and the potential for participant awareness of treatment assignments. Investigators note that future trials must focus on populations with documented iodine deficiency, particularly among lower socioeconomic groups. Experts recommend longer treatment durations and extended follow-up periods to better understand the long-term efficacy of higher iodine dosages.

Iodine remains a critical micronutrient, typically sourced through iodised salt, seafood, and dairy.

The findings current to May 2025 show that while iodine is important for preventing intellectual disability and central nervous system delays, it can be given as iodised oil injected into a muscle or as oral potassium iodide tablets, capsules, or drops.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice.