Iodine Deficiency and Iodine Supplements

Iodine is essential for making thyroid hormones, which in turn is needed for important bodily functions such as controlling metabolism, proper brain and bone development in the fetus and during infancy. Hence, iodine is significant for everyone with pregnant women and infants being the neediest group.

Causes for Iodine deficiency

Those who suffer from iodine deficiency can have many health problems the most serious being mental retardation in children that

is easily preventable. The body uses Thyroid Stimulating Hormone (TSH) to strictly control thyroid hormone levels. When iodine levels fall below normal (100 mcg/day), then TSH secretion increases. This increase the uptake of thyroidal iodine found in the blood and augments creation of thyroid hormone. If iodine levels are very low, then despite elevated levels of TSH, thyroid hormone manufacture is reduced.

While most people in industrialized countries like the US or Canada do not suffer from iodine deficiency, world over it is a serious health problem. It is estimated that around 2.2 billion people are in iodine deficient areas and are at great risk. 

Regions where there is iodine-deficient soil : People who live in mountainous regions of the Alps, Andes and Himalayan regions or in river valley regions of South / Southeast Asia prone to flooding are at risk since the soil found in these regions are deficient in iodine. These people must ensure they increase their use of iodized salt and that they purchase foods made outside their own iodine-deficient regions.

Foods that have goitrogens : Soy, cassava, broccoli, cabbage, cauliflower and similar cruciferous vegetables are high in goitrogens. This interferes with the absorption of iodine by the thyroid gland and therefore increases risk of deficiency even in those with marginal iodine status. Foods that are deficient in vitamin A or iron are also goitrogenic. If you live in an area that is not iodine deficient and eat a well-rounded diet, then eating these foods does not pose a risk.

Recommended Dosage of Iodine

recommended iodine dosage


Lack of Iodized Salt : Using iodized salt is a must to prevent iodine deficiency. Surprisingly while this is available easily in many countries, there are still regions in Europe (apart from Western Europe), Africa, Eastern Mediterranean and Southeast Asia where a significant proportion of the population are unable to get iodized salt. According to statistics provided by the UNICEF and WHO, 31% of school-age children eat foods deficient in iodized salt.

Pregnant Women : Even in an advanced economy like the US, many pregnant women do suffer from insufficiency of iodine. The impact of lack of iodine on serious developmental problems for the fetus was not known until recently. 

Symptoms of iodine deficiency

  • Goiter that results in a very large thyroid gland is the first sign of iodine deficiency or in fact excessive iodine too. The swelling is at the neck and can be a large lump or a small nodule. When swelling due to goiter is very big, it can place pressure on the esophagus and windpipe and this leads to wheezing, cough, swallowing or breathing difficulties.
  • Hypothyroidism is a common condition that affects 3-5% of people – especially women. Iodine deficiency causes severe hypothyroidism. The symptoms of this disease are so subtle that often it is mistaken for aging. Here are some of the common symptoms:

    • Depression
    • Weight gain
    • Fatigue
    • Intolerance to cold
    • Sleepiness
    • Constipation
    • Muscle cramps
    • Dry skin, coarse hair
    • Reduced levels of concentration
    • Increased cholesterol levels
    • Swelling of legs

When a patient displays these symptoms, a test must be conducted for hypothyroidism. Measurement of TSH is the main test and if a person suffers from hypothyroidism, the levels will be elevated.

Other symptoms of iodine deficiency are:

  • Pregnant women with iodine deficiency can experience

    • High blood pressure
    • Miscarriage
    • Stillbirths
    • Neurological problems in the fetus
  • Neurological abnormalities in infants like

    • Cretinism
    • Stunted growth
    • Delayed sexual maturation
    • Motor spasticity
    • Mental retardation
  • Women who suffer from iodine deficiency can

    • Stop ovulating
    • Become infertile
    • Be susceptible to ovarian and breast cancer
  • Men who suffer from iodine deficiency can be at risk of contracting prostate cancer

Iodine Supplements

Iodine supplements (as sodium iodide) are available in the form of a multivitamin or as a topical medication used to treat wounds. Potassium iodide is used to treat cases of exposure to radiation. The daily recommended dosage of iodine is 0.14mg for adults.Hypothyroidism

Precautions while taking iodine supplements

There are many side effects linked to high doses of iodine and its interaction with other medication. Iodine supplements can interact with medications taken to treat hypothyroidism and high blood pressure (ACE inhibitors). There is also an adverse reaction when there is an increase in potassium in the body when potassium iodide and potassium-sparing diuretics are taken together. Hence, it must be taken under medical supervision. 

High doses can block creation of thyroid hormones therefore causing hypothyroidism. It also increases the risk of contracting other health problems like Graves’ disease, Hashimoto’s disease, thyroid papillary cancer, thyroiditis and thyrotoxicosis. The last is a serious condition resulting from high levels of thyroid hormones entering the bloodstream. 

Acute iodine poisoning, usually rare, has symptoms that include fever, burning of stomach, throat and mouth, nausea, abdominal pain, diarrhea, nausea, weak pulse or coma. Those who have autoimmune thyroid disease may suffer from adverse effects of iodine intake that is generally considered safe for most people.

Those suffering from tuberculosis or kidney diseases must restrict intake of iodine. If topical iodine is used on babies, they must have routine thyroid tests done.

Those with dermatitis herpetiformis can see their symptoms worsening when they take iodine. 


The consequences of iodine deficiency are serious and can occur in people of all ages. Since this is a common health problem all over the world, it needs to be tackled on a war footing by the countries most at risk. Apart from iodine supplements, foods enriched in iodine prevent this deficiency and attendant health problems.