What is Iodine and Why Do Indians Need It
Iodine is an essential mineral required for the production of thyroid hormones, which regulate metabolism, growth, brain development, and energy production. India has a long history with iodine deficiency: the introduction of universal salt iodisation in the 1980s and 1990s was one of the most successful public health nutrition interventions in Indian history, dramatically reducing goitre and cretinism in previously endemic regions.
The story, however, does not end there. Deficiency persists in specific populations, and emerging concerns about both deficiency and excess iodine intake make this worth understanding.
Who is still at risk in India
People who use non-iodised salt, including rock salt (sendha namak) and certain specialty salts, as their primary salt source. Populations in areas where iodised salt distribution has been inconsistent. Pregnant and breastfeeding women, whose iodine requirements increase significantly and whose deficiency has direct consequences for foetal and infant brain development. People with high goitrogen intake from raw cruciferous vegetables and soy without adequate iodine to compensate.
What iodine deficiency does
Mild deficiency causes subtle reductions in thyroid hormone production that manifest as fatigue, weight gain, brain fog, and reduced cognitive function without the dramatic symptoms of severe deficiency. In pregnancy, even mild iodine deficiency during the first trimester, when the foetal brain is developing most rapidly, can reduce IQ by 10 to 15 points in the child. This is one of the most preventable causes of cognitive impairment globally.
Food sources of iodine in India
Iodised salt is the primary source for most Indians and should remain the default. Dairy products including milk and curd contain iodine from cattle feed. Eggs provide a meaningful amount. Seafood is the richest natural source: sardines, shrimp, and fish contain significant iodine, relevant for coastal populations.
For people avoiding iodised salt or following dairy-free diets, iodine supplementation is worth discussing with a doctor, particularly during pregnancy and breastfeeding.
The upper limit
Excess iodine can also cause thyroid dysfunction, particularly in people with existing thyroid conditions. This is relevant for people taking kelp or seaweed supplements, which can contain very high iodine levels. Supplementation beyond dietary sources should be guided by testing rather than assumption.