What is iodine deficiency?
Before the 1920s, iodine deficiency was common in the Great Lakes, Appalachian, and Northwestern U.S. regions and in most of Canada. Treatment of iodine deficiency by the introduction of iodized salt has virtually eliminated the “goiter belt” in these areas. However, many other parts of the world do not have enough iodine available through their diet and iodine deficiency continues to be an important public health problem globally. Approximately 40% of the world’s population remains at risk for iodine deficiency.
|SYMPTOMSWhat are the 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 (develops a goiter) as it tries to keep up with demand for thyroid hormone production. Worldwide, iodine deficiency is the most common cause of thyroid enlargement and goiter (see Goiter brochure). 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, iodine deficiency is the most common cause of hypothyroidism worldwide (see Hypothyroidism brochure).
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 mental retardation 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, mental retardation, deaf mutism, spasticity, and short stature), though this is not seen in the United States. Congenital hypothyroidism due to iodine deficiency is the most common preventable cause of mental retardation in the world. Even mild iodine deficiency during pregnancy, which may be present in some women in the United States, may be associated with low intelligence in children.
What are the causes of iodine iodine deficiency?
How do you diagnose iodine deficiency?
In the United States, iodine status has remained generally adequate in the last 2 decades although studies have shown that urinary iodine levels dropped by about half between the early 1970s and the early 1990s. However, iodine deficiency is a major issue in other parts of the world, including parts of Europe, Africa and Asia.
How is iodine deficiency treated?
How is iodine deficiency prevented?
United States Recommendations - The Institute of Medicine has set the Recommended Dietary Allowance (RDA) for iodine in adult men and women at 150 μg per day. Individuals who add table salt to their food regularly should use iodized salt. One teaspoon of iodized salt contains approximately 400 μg iodine. Most iodine-containing multivitamins have at least 150 μg iodine, but only about half of the types of multivitamins in the U.S. contain iodine.
The RDA is 220 μg iodine per day for pregnant women and 290 μg iodine per day for breastfeeding women. Because the effects of iodine deficiency are most severe in pregnant women and their babies, the American Thyroid Association has recommended that all pregnant and breastfeeding women in the U.S. and Canada take a prenatal multivitamin containing 150 μg iodine per day.
Are there problems with taking too much iodine?
In addition, individuals who move from an iodine-deficient region (for example, parts of Europe) to a region with adequate iodine intake (for example, the United States) may also develop thyroid problems since their thyroids have become very good at taking up and using small amounts of iodine. In particular, these patients may develop iodine-induced hyperthyroidism
| american thyroid association website www.thyroid.org 2011
FROM MEDLINE PLUS - 2011
What is it?
Iodine is a chemical element. The body needs iodine but cannot make it. The needed iodine must come from the diet. As a rule, there is very little iodine in food, unless it has been added during processing, which is now the case with salt. Most of the world’s iodine is found in the ocean, where it is concentrated by sea life, especially seaweed.
The thyroid gland needs iodine to make hormones. If the thyroid doesn’t have enough iodine to do its job, feedback systems in the body cause the thyroid to work harder. This can cause an enlarged thyroid gland (goiter), which becomes evident as a swollen neck.
Other consequences of not having enough iodine (iodine deficiency) are also serious. Iodine deficiency and the resulting low levels of thyroid hormone can cause women to stop ovulating, leading to infertility. Iodine deficiency can also lead to an autoimmune disease of the thyroid and may increase the risk of getting thyroid cancer. Some researchers think that iodine deficiency might also increase the risk of other cancers such as prostate, breast, endometrial, and ovarian cancer.
Iodine deficiency during pregnancy is serious for both the mother and the baby. It can lead to high blood pressure during pregnancy for the mother, and mental retardation for the baby. Iodine plays an important role in development of the central nervous system. In extreme cases, iodine deficiency can lead to cretinism, a disorder that involves severely stunted physical and mental growth.
Iodine deficiency is a common world health problem. The most recognized form of deficiency is goiter. Additionally, across the globe iodine deficiency is thought to be the most common preventable cause of mental retardation. Early in the twentieth century, iodine deficiency was common in the US and Canada, but the addition of iodine to salt has improved public health. The addition of iodine to salt is required in Canada. In the US, iodized salt is not required, but it is widely available. Researchers estimate that iodized salt is used regularly by about half the US population.
Iodine is used to prevent iodine deficiency and its consequences, including goiter. It is also used for treating a skin disease caused by a fungus (cutaneous sporotrichosis); treating fibrocystic breast disease; preventing breast cancer, eye disease, diabetes, and heart disease and stroke; and as an expectorant.
Iodine is also used to for radiation emergencies, to protect the thyroid gland against radioactive iodides. Potassium iodide tablets for use in a radiation emergency are available as FDA-approved products (ThyroShield, Iosat) and on the Internet as food supplements. Potassium iodide should only be used in a radiation emergency, not in advance of an emergency to prevent sickness.
Iodine is applied to the skin to kill germs, prevent soreness inside the mouth (mucositis) caused by chemotherapy, and treat diabetic ulcers.
Iodine is also used for water purification.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for IODINE are as follows:
Likely effective for…
Possibly effective for…
Insufficient evidence to rate effectiveness for…
How does it work?
Iodine reduces thyroid hormone and can kill fungus, bacteria, and other microorganisms such as amoebas. A specific kind of iodine called potassium iodide is also used to treat (but not prevent) the effects of a radioactive accident.
Are there safety concerns?
Iodine is LIKELY SAFE for most people when taken by mouth at recommended amounts.
Iodine can cause significant side effects in some people. Common side effects include nausea and stomach pain, runny nose, headache, metallic taste, and diarrhea.
In sensitive people, iodine can cause side effects including swelling of the lips and face (angioedema), severe bleeding and bruising, fever, joint pain, lymph node enlargement, allergic reactions including hives, and death.
Large amounts or long-term use of iodine are POSSIBLY UNSAFE. Adults should avoid prolonged use of doses higher than 1100 mcg per day (the upper tolerable limit, UL) without proper medical supervision. In children, doses should not exceed 200 mcg per day for children 1 to 3 years old, 300 mcg per day for children 4 to 8 years old, 600 mcg per day for children 9 to 13 years old, and 900 mcg per day for adolescents. These are the upper tolerable limits (UL).
In both children and adults, there is concern that higher intake can increase the risk of side effects such as thyroid problems. Iodine in larger amounts can cause metallic taste, soreness of teeth and gums, burning in mouth and throat, increased saliva, throat inflammation, stomach upset, diarrhea, wasting, depression, skin problems, and many other side effects.
When iodine is used directly on the skin, it can cause skin irritation, stains, allergic reactions, and other side effects. Be careful not to bandage or tightly cover areas that have been treated with iodine to avoid iodine burn.
Special precautions & warnings:
Pregnancy and breast-feeding: Iodine is LIKELY SAFE when taken by mouth in recommended amounts. Do not take more than 1100 mcg of iodine per day if you are over 18 years old; do not take more than 900 mcg of iodine per day if you are 14 to 18 years old. Higher intake might cause thyroid problems. The topical product (2% solution) is LIKELY SAFE for use on the skin.
Autoimmune thyroid disease: People with autoimmune thyroid disease may be especially sensitive to the harmful side effects of iodine.
Rash called dermatitis herpetiformis: Taking iodine can cause worsening of this rash.
Thyroid disorders, such as too little thyroid function (hypothyroidism), an enlarged thyroid gland (goiter), or a thyroid tumor: Prolonged use or high doses of iodine might make these conditions worse.
Are there interactions with medications?
Do not take this combination.
Medications for an overactive thyroid (Antithyroid drugs)
Iodine can affect the thyroid. Taking iodine along with medications for an overactive thyroid might decrease the thyroid too much. Do not take iodine supplements if you are taking medications for an overactive thyroid.
Some of these medications include methenamine mandelate (Methimazole), methimazole (Tapazole), potassium iodide (Thyro-Block), and others.
Be cautious with this combination.
Amiodarone (Cordarone) contains iodine. Taking iodine supplements along with amiodarone (Cordarone) might cause too much iodine in the blood. Too much iodine in the blood can cause side effects that affect the thyroid.
Large amounts of iodine can decrease thyroid function. Lithium can increase iodine’s effects on the thyroid. Taking iodine along with lithium might decrease the thyroid function too much. Do not take large amounts of iodine if you are taking lithium.
Medications for high blood pressure (ACE inhibitors)
Some medications for high blood pressure might decrease how quickly the body gets rid of potassium. Most iodide supplements contain potassium. Taking potassium iodide along with some medications for high blood pressure might cause too much potassium in the body. Do not take potassium iodide if you are taking medications for high blood pressure.
Some medications for high blood pressure include captopril (Capoten), enalapril (Vasotec), lisinopril (Prinivil, Zestril), ramipril (Altace), and others.
Medications for high blood pressure (Angiotensin receptor blockers (ARBs))
Some medications for high blood pressure might decrease how quickly the body gets rid of potassium. Most iodine supplements contain potassium. Taking potassium iodide along with some medications for high blood pressure might cause too much potassium in the body. Do not take potassium iodide if you are taking medications for high blood pressure.
The ARBs include losartan (Cozaar), valsartan (Diovan), irbesartan (Avapro), candesartan (Atacand), telmisartan (Micardis), and eprosartan (Teveten).
Water pills (Potassium-sparing diuretics)
Most iodine supplements contain potassium. Some “water pills” might also increase potassium in the body. Taking potassium iodide along with some “water pills” might cause too much potassium to be in the body. Do not take potassium iodide if you are taking “water pills” that increase potassium in the body.
Some “water pills” that increase potassium in the body include spironolactone (Aldactone), triamterene (Dyrenium), and amiloride (Midamor).
Are there interactions with herbs and supplements?
There are no known interactions with herbs and supplements.
Are there interactions with foods?
There are no known interactions with foods.
What dose is used?
The following doses have been studied in scientific research:
The National Institute of Medicine has set Adequate Intake (AI) of iodine for infants: 0 to 6 months, 110 mcg/day; 7 to 12 months, 130 mcg/day.
For children and adults, Recommended Dietary Amounts (RDA) have been set: children 1 to 8 years, 90 mcg/day; 9 to 13 years, 120 mcg/day; people age 14 and older, 150 mcg/day. For pregnant women, the RDA is 209 mcg/day, and breastfeeding women, 290 mcg/day.
Tolerable Upper Intake Levels (UL), the highest level of intake that is not likely to cause unwanted side effects, for iodine intake have been set: children 1 to 3 years, 200 mcg/day; 4 to 8 years, 300 mcg/day; 9 to 13 years, 600 mcg/day; 14 to 18 years (including pregnancy and breastfeeding), 900 mcg/day. For adults older than age 19 including pregnant and breastfeeding women, the Tolerable Upper Intake Level is 1100 mcg/day.
Atomic number 53, Cadexomer Iodine, Diatomic Iodine, I2, Iode, Iodide, Iodized Salt, KI, Lugol’s Solution, Molecular Iodine, Monoatomic Iodine, Potassium Iodide, Povidone Iodine, Saturated Solution Potassium Iodide, Sodium Iodide, Sodium Iodine, Sodium Periodate, SSKI, Yodo.
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
Last reviewed – 04/02/2011
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