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Iodine deficiency can cause low IQ levels – A half teaspoon of iodised salt to diet can prevent Iodine Deficiency Disorders


Iodine deficiency disorders or IDD are widespread in many parts of the world. To spread awareness among population about the essential dietary element iodine and its  importance, to identify iodine rich  sources and educate people to add in their diet, to clarify peoples doubts every year on 21st October world iodine deficiency day is observed. Iodine is one of the essential micronutrients required for normal growth and development of the human body and brain. Recommended Dietary Allowance (RDA) for iodine is 100 – 150 μg per day.


The human body uses iodine to make thyroid hormones that is why an iodine deficiency can cause hypothyroidism. Inadequate thyroid hormone production adversely affects, resulting in metabolic problems known collectively as iodine deficiency disorders or IDD.

Iodine is very low in the foods grown at high altitudes. Soils from mountain ranges and from areas with frequent flooding are most likely to be iodine deficient. The problem is more aggravated by deforestation and soil erosion.

Poverty, malnutrition, particularly intake of goitrogens (cruciferous vegetables like cabbage, cauliflower, broccoli and radish contain goitrogens) through unusual diets by poor, contaminated drinking water, which interfere with the intestinal absorption of iodine are some others reasons for IDD.

Antagonists: Goitrogens are chemical substances that occur primarily in plant food.   Vegetables of brassica spececies like cabbage, cauliflower, broccoli and radish contain glucosinolates (thiogluosides) which are potential goitrogens. Eating too much of these foods inhibits the availability of iodine to the body from the food and thus leads to the development of goiter. They can occasionally be present in contaminated drinking water. Goitrogens interfere in thyroxin synthesis by inhibiting the enzymes involved in the synthesis of thyroxin.  This will lead to Iodine deficiency.


Iodine deficiency can cause low IQ levels in children and may reduce adult’s ability to work and think wisely.

Goitre (swelling of thyroid gland in the neck) iodine intakes consistently lower than 50 μg per day will usually result in goiter), Hypothyroid (low metabolism), cretinism (poor growth), fatigue, slow metabolism, depression and fetal mental retardation are some of the iodine deficiency disorders.

Pregnancy and  lactation also require iodine to make adequate thyroid hormones, which play a crucial role in the fetal growth and  brain development.


The human body does not produce iodine; 60 – 70 % of iodine needs are met by the iodine present in the diet and water. To combat iodine deficiency disorders, food products and water supply are fortified with iodine. In practice common salt was fortified with iodine.

Sources of iodine:

  • Iodised salt consumption is the cheap and best cost effective source of iodine. 30% of iodine is lost during cooking and remaining 70% is absorbed by the body. Iodine loss depends on the time and method of cooking. To prevent iodine loss, sprinkle salt on food after complete cooking rather than adding salt while cooking.
  • Dairy products are other options to get iodine. Fortification of Milk, yogurt and cheese can be the sources of iodine.
  • Iodine found in sea-water is 0.2 mg per litre. Seafood’s such as Fish (such as cod and tuna), seaweed, shrimp, and other seafood, which are generally rich in iodine.


People should get most of the nutrients from food, dietary supplements and fortified foods may provide nutrients, if consumed less than daily recommended amounts.

Iodine supplementation should be taken only under medical supervision if there is a deficiency, eating a healthy and balanced diet is good enough to meet your daily iodine needs. Deficiency is easy to prevent, since prevention is better than cure educating the benefits of iodine among people may help to eat right and adapt to a healthy lifestyle.

Take home message from Nutritionist: Just add a half teaspoon (3grams) of iodised salt to diet, is good enough to meet your daily requirement of iodine.  Eg : Add half teaspoon of iodised salt to 1 glass of buttermilk(200ML).

Article is written by V. Krishna Deepika, Clinical Dietician, Apollo Spectra Hospitals, Kondapur, Hyderabad.

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