Iodine supplementation results in a slight increase in cognitive function compared to placebo in children and adolescents, according to a meta-analysis published in The Cochrane database of systematic reviews on September 10, 2026.

The review, identified by PubMed ID 42720098 and doi 10.1002/14651858.CD014475.pub2, drew on a single study with 166 participants over 28 weeks. The standardized mean difference was 0.19 (95% CI 0.04 to 0.34), rated as high-certainty evidence by the authors.

Iodine supplementation may result in little to no difference in children's weight compared to placebo, with a mean difference of -0.20 kg (95% CI -1.92 to 1.5). The analysis did not report other anthropometric or clinical outcomes.

The read here is that the cognitive effect, while modest, is supported by high-certainty evidence from a single trial, which limits generalizability. No additional studies were pooled for the primary endpoint.