Iodine supplementation is an effective way to reduce iodine deficiency, but precautions must be taken to prevent excessive intake. Bioavailability of iodine from food varies and interactions between different foods within the food matrix are not well established. The most practical and cost-effective way to provide iodine supplementation to deficient populations is with iodized salt, as advocated by several international organizations such as WHO, United Nations Children’s Fund, and International Council for Control of Iodine Deficiency Disorders. Other approaches include consumption of iodized water, iodized oil, and iodine tablets. Quantity and type of Iodine used for salt fortification varies by region and typically ranges between 20 and 40 mg iodine/kg salt.

Universal iodization of edible salt was the intervention strategy recommended to prevent and control IDD. In 2005, universal salt iodisation was made mandatory in the country.

According to the India Iodine Survey, 2018–19, the household coverage of edible salt with adequate iodine (content ≥15 parts/million -ppm) was 76.3%. At the sub-national level, the coverage varied, with 10 states and 3 UTs achieving USI and 11 states and 2 UTs falling below the national average, with the highest among all the states and UTs, being Jammu and Kashmir and the lowest being Tamil Nadu.

Other sources of Iodine: –

• Seaweed (e.g., kelp, nori, kombu, and wakame)

• Seafoods including fish such as tuna, cod and eggs

• Human breast milk and infant formulas

• Dairy products such as milk, yoghurt and cheese. However, the amount varies by whether the cows received iodine feed supplements

• Most commercially prepared bread contains very little iodine unless the manufacturer has used potassium iodate or calcium iodate as a dough conditioner

• Fruits and vegetables contain iodine, but the amount varies based on the soil that they grow in. Good sources include prunes, lima beans.

Goitrogens: – Goitrogens are substances found in cruciferous vegetables, such as cabbage and Brussels sprouts, and soy products that may interfere with thyroid hormone production. Most people, including those with hypothyroidism, can enjoy moderate amounts of goitrogenic foods without negatively affecting their thyroid health.

Although progress has been made in many parts of the world that have improved iodine status, there are still many areas and specific populations in need of iodine supplementation. The national bodies playing key roles in National Iodine Deficiency Disorders Control Program (NIDDCP) need to be strengthened and more awareness regarding iodine deficiency looks beyond essential.

(Author: Vilasini Bhaskaran, Specialist Registered Dietitian, NHS UK; Dietetic Lead, Practo India)