Why is salt iodized?
Iodine is found in many food items and is a mineral that is mixed in table salt. Human body requires iodine in very small quantities. But, it is essential for human health. The hormone thyroxine comprises of iodine and helps in improving the rate of metabolism in human body. Iodine was available previously in sea and soil under the sea. Iodine was available in sea foods like sea trout, shrimp, and shark and so on. It was also available in vegetables grown in the soil containing iodine and in plants that grew on the soil rich in iodine. Milk and cheese were having high amounts of iodine. So there were many other ways of getting iodine in the food other than in table salt. But that was not always possible.
When iodine was not plenty in food supply people were depending on the sea for iodine. Those who were living far away from the sea were suffering from iodine deficiency. Salt fortification was started in US to treat the people with goiter. Iodine deficiency results in Goiter, in thyroid gland. As the food containing iodine is manufactured and shipped to many other parts of the world, iodine deficiency is rarely found. Those living far off from the sea also are less likely to get the disease called goiter. As salt fortification and iodine levels in the food grown on the soil rich in iodine is not sufficient for the people to be healthy; salt is iodized.
Recently, it was found that goiter is mostly available in developing countries as they have insufficient access to sea foods and plants grown on soil rich in iodine. The under-nourished people in developing countries suffer from iodine deficiency. If we are eating plenty of sea foods, plants grown in iodine rich soil and vegetables in the sea are sufficient for fulfilling the iodine needs of the body. If the people are facing the insufficiency of getting the above mentioned iodine rich food supply then it is necessary for them to have iodine rich salt in their food. So, salt is iodized to cover up the iodine necessities of the human body. The recommended daily allowance of iodine for an adult is 150 ug / day. Iodine deficiency also leads to cretinism (developmental and mental delay).