Chennai: Tamil Nadu is India’s second-largest salt producer, but it had the lowest share of households using adequately iodised salt among all states in the latest survey the state cites, health minister K G Arunraj said on Monday at an event organised for the iodine deficiency disorders prevention day at Justice Basheer Ahmed Sayeed College for Women.
The 2018-19 India iodine survey found that only 62% of Tamil Nadu households used adequately iodised salt, against a national average of 76%. A recent study by a city-based medical institution found that rural residents eat about 13 g of salt a day and a third of households use salt with too little iodine. WHO says iodine deficiency is the leading preventable cause of brain damage, Arunraj said, adding that studies show children in iodine-deficient communities score 10 to 15 IQ points lower on average. Data released in parts by the department on Monday showed goitre in 9% of schoolchildren screened in Ramanathapuram in 2024-25. Villupuram recorded about the same share, 9%, in 2018-19. Madurai reported 6% in 2022-23, and Pudukottai recorded 5% in 2024-25.
“We cannot accept iodine deficiency in the land that produces the salt,” he said. Many families buy loose, unbranded rock salt, store it in open containers exposed to sun and moisture, and add salt early in cooking and boil it for long, which lets the iodine escape, Arunraj said. The thyroid gland uses it to produce hormones that govern growth and metabolism, and that guide the developing brain, said director of public health Dr A Somasundaram. All these districts, officials said, are considered high risk for goitre. The health minister said the food safety department initiates action against manufacturers for violations. “This action will continue with greater intensity,” he said. The state runs a campaign to reduce salt intake, aimed at preventing hypertension, heart disease, stroke and kidney damage, he said. “It means we must use less than 5g a day, but only iodised salt,” he added.
Iodine is a trace mineral, needed in tiny amounts, that the body cannot make. The stakes are highest in pregnancy, when a fetus depends entirely on its mother’s supply. The public health department tests schoolchildren for goitre in every district.