What is iodine deficiency?
Iodine deficiency is a lack of the trace element iodine, an essential nutrient in the diet. It may result in metabolic problems such as goiter, sometimes as an endemic goiter as well as cretinism due to untreated congenital hypothyroidism, which results in developmental delays and other health problems. Iodine deficiency is an important global health issue, especially for fertile and pregnant women. It is also a preventable cause of intellectual disability.
Causes of iodine deficiency
Our bodies do not produce iodine, so it must come from our diet. Iodine deficiency is rare in the United States, partly due to widespread use of iodized salt. Because animal feed is also often supplemented with iodine, meat and dairy products tend to be high in iodine.
Natural sources of iodine include food from the sea and from areas where the soil is rich in iodine. Worldwide, mountainous areas and inland lowlands far from the oceans tend to have iodine-poor soil. These are the areas where iodine deficiency is most common.
Reducing your risk of iodine deficiency
You may be able to lower your risk of iodine deficiency by:
- Eating foods grown in iodine-rich soils
- Eating meat and dairy products
- Eating seafood
- Taking vitamin and mineral supplements that contain iodine
- Using iodized salt
Symptoms of Iodine deficiency
All of the symptoms of iodine deficiency are related to its effect on the thyroid:
Goiter: Without adequate iodine, the thyroid progressively enlarges as it tries to keep up with the demand for thyroid hormone production. Worldwide, iodine deficiency is the most common cause of thyroid enlargement and goitre. Within a goiter, nodules can develop. Patients with a large goiter may experience symptoms of choking, especially when lying down, and difficulty swallowing and breathing.
Hypothyroidism: As the body’s iodine levels fall, hypothyroidism may develop, since iodine is essential for making thyroid hormone. While this is uncommon in the United States, this disease is the most common cause of hypothyroidism worldwide.
Pregnancy-related problems: Iodine deficiency is especially important in women who are pregnant or nursing their infants. Severe iodine deficiency in the mother has been associated with miscarriages, stillbirth, preterm delivery, and congenital abnormalities in their babies. Children of mothers with severe iodine deficiency during pregnancy can have intellectual disabilities and problems with growth, hearing, and speech. In the most severe form, an underactive thyroid can result in cretinism (a syndrome characterized by permanent brain damage, deaf-mutism, spasticity, and short stature), although this has become rare worldwide. This deficiency is the most common preventable cause of intellectual disabilities in the world. Even mild deficiency during pregnancy, which may be present in some women in the United States, may be associated with low intelligence in children.
If your physician suspects you have an iodine deficiency, they will normally monitor your iodine levels in one of four ways:
Urine test: This is the humblest and fastest test. You can get results in minutes, but it is not as accurate as some of the other iodine tests.
Blood test: This is a simple and accurate test of the levels of iodine in the body. However, the reading takes longer than a urine test.
Iodine patch test: The iodine patch test is a test in which doctors paint an iodine patch on the skin and check its appearance 24 hours later. For those who are not iodine-deficient, the patch fades no earlier than 24 hours. But a deficiency will probably cause the iodine to be engrossed into the skin more quickly. This test is not the most accurate, but it is inexpensive and relatively fast.
Iodine load test: This test measures the amount of iodine you excrete in your urine over a 24-hour period. It is not the fastest test, and not the most convenient either. (You should collect all the urine samples you have in a 24-hour period.) But it is quite accurate.
The main treatment for iodine deficiency is avoiding it in the first place. The introduction of iodized salt has greatly reduced the occurrence of deficiency in the United States and throughout many parts of the world.
The treatment is iodine replacement. Adding iodized table salt and foods high in iodine to the diet may be enough to achieve normal iodine levels. Sometimes vitamin and mineral supplements containing iodine may be used. Because iodine is so important during fetal and early childhood development, women who are pregnant or breastfeeding should take multivitamins that include iodine.
Occasionally, the thyroid gland may need to be removed. This is particularly true if a large goiter makes it difficult to swallow or breathe. Thyroid replacement hormones are required if the thyroid is removed.
As with many diseases, it is better to prevent the problem than to have to treat it. For the past 80 years, efforts have been made around the world to eliminate this disease. Eliminating this deficiency has been one of the main goals of the Global Iodine Network, UNICEF, and the World health organization. Iodized salt has been the mainstay of iodine deficiency prevention around the world. In regions where iodized salt is not widely available, the use of a daily supplement containing iodine may be recommended for pregnant and lactating women. Iodized oil injections are occasionally used in highly iodine-deficient regions of the world, where widespread use of iodized salt is not possible.