Excessive Iodine in Iranian Salt and Its Metabolic Implications: A Critique of the Uniform Iodization Policy (40–60 ppm)

The National Salt Iodization Program stands as one of the most successful public health interventions in Iran’s history. Prevalence of goiter among schoolchildren plummeted from approximately 68% in 1989 to less than 7% by 2007, leading the World Health Organization (WHO) to declare Iran ‘iodine-sufficient’ (Mehran, Shahid Beheshti University of Medical Sciences). However, this success was accompanied by a non-targeted design flaw: the implementation of a uniform dosage of 40 mg/kg of potassium iodate (40 ppm, with a range extending up to 60 ppm) across the entire population, without regard for individual metabolic profiles, thyroid status, or varying salt intake. Currently, salt consumption in Iran is estimated at 10–12 g/day—nearly double the WHO recommendation (Golestan University of Medical Sciences)—creating a critical intersection between ‘excessive salt intake’ and ‘high/uniform iodine concentration.’ Consequently, a significant portion of the population receives iodine levels far exceeding physiological requirements. Emerging international evidence suggests that chronic exposure to excess iodine is linked to inflammatory pathways, autoimmune thyroiditis, subclinical hypothyroidism, impaired glucose and lipid metabolism, and oxidative stress, particularly within germ cells, leading to diminished sperm quality. Therefore, it is plausible that a subset of the rising prevalence of inflammatory diseases, metabolic syndrome, obesity, reproductive disorders, and non-communicable diseases (NCDs) may be attributable to indiscriminate iodization and the failure to tailor iodine intake to individual metabolic needs.