How much iodine should i take a day

In addition, specialty salts, such as sea salt, kosher salt, Himalayan salt, and fleur de sel, are not usually iodized. Iodine is available in dietary supplements, usually in the form of potassium iodide or sodium iodide. Many multivitamin-mineral supplements contain iodine. Dietary supplements of iodine-containing kelp a seaweed are also available. Most people in the United States get enough iodine from foods and beverages.

However, certain groups of people are more likely than others to have trouble getting enough iodine:. Iodine deficiency is uncommon in the United States and Canada. People who don't get enough iodine cannot make sufficient amounts of thyroid hormone.

This can cause many problems. In pregnant women, severe iodine deficiency can permanently harm the fetus by causing stunted growth , intellectual disability, and delayed sexual development. Less severe iodine deficiency can cause lower-than-average IQ in infants and children and decrease adults' ability to work and think clearly.

Goiter , an enlarged thyroid gland , is often the first visible sign of iodine deficiency. Scientists are studying iodine to understand how it affects health. Here are some examples of what this research has shown. Women who are pregnant or breastfeeding need to get enough iodine for their babies to grow and develop properly.

Breastfed infants get iodine from breast milk. However, the iodine content of breast milk depends on how much iodine the mother gets. To make adequate amounts of iodine available for proper fetal and infant development, several national and international groups recommend that pregnant and breastfeeding women and infants take iodine supplements.

The American Thyroid Association recommends that women who are pregnant, planning to become pregnant, or breastfeeding take a daily supplement containing mcg iodine as potassium iodide. The American Academy of Pediatrics has similar guidance. However, only about half the prenatal multivitamins sold in the United States contain iodine. Severe iodine deficiency during childhood has harmful effects on the development of the brain and nervous system.

The effects of mild iodine deficiency during childhood are more difficult to measure, but mild iodine deficiency might cause subtle problems with neurological development.

Giving iodine supplements to children with mild iodine deficiency improves their reasoning abilities and overall cognitive function. In children living in iodine-deficient areas, iodine supplements seem to improve both physical and mental development.

More study is needed to fully understand the effects of mild iodine deficiency and of iodine supplements on cognitive function. Although not harmful, fibrocystic breast disease causes lumpy, painful breasts. The median iodine content was mcg per daily serving, with a range of 25 to mcg; 25 of the 34 provided iodine as potassium iodide.

Results from a study however, raise some questions as to the safety of widespread iodine supplementation in areas of relative iodine sufficiency.

These findings suggest that taking higher doses of supplemental iodine during pregnancy could induce thyroid dysfunction in some women and underscore the need for additional research into the effects on maternal thyroid function of iodine supplementation during pregnancy. Many researchers, as well as the American Thyroid Association, stress the importance of continued iodine status monitoring among women of reproductive age [ 1 , 4 , 31 , 37 , 55 , 69 , 70 ].

Cognitive function during childhood The effects of severe iodine deficiency on neurological development are well documented. Results from several studies suggest, for example, that chronic, moderate-to-severe iodine deficiency, particularly in children, reduces IQ by about 12— A Cochrane review concluded that iodine supplementation in children living in areas of iodine deficiency appears to both positively affect physical and mental development and decrease mortality with only minor and transient adverse effects [ 71 ].

The effects of mild iodine deficiency during childhood are more difficult to quantify. Some research suggests that mild iodine deficiency is associated with subtle neurodevelopmental deficits and that iodine supplementation might improve cognitive function in mildly iodine-deficient children [ 51 ]. These findings suggest that correcting mild iodine deficiency in children could improve certain components of cognition.

Additional research is required to fully understand the effects of mild iodine deficiency and iodine supplementation on cognitive function. Fibrocystic breast disease Fibrocystic breast disease is a benign condition characterized by lumpy, painful breasts and palpable fibrosis.

It commonly affects women of reproductive age, but it can also occur during menopause, especially in women taking estrogens [ 73 ]. Breast tissue has a high concentration of iodine, especially during pregnancy and lactation [ 4 , 74 ].

Some research suggests that iodine supplementation might be helpful for fibrocystic breast disease, although a specific mechanism of action has not been established [ 75 ] and data are limited. A more recent randomized, double-blind, placebo-controlled clinical trial had similar findings.

In this study, researchers randomly assigned women 18—50 years of age with fibrosis and a history of breast pain to receive tablets containing 0 mcg, 1, mcg, 3, mcg, or 6, mcg of iodine per day [ 75 ]. After 5 months of treatment, women receiving doses of 3, or 6, mcg iodine had a significant decrease in breast pain, tenderness, and nodularity compared with those receiving placebo or 1, mcg iodine. The researchers also reported a dose-dependent reduction in self-assessed pain.

None of the doses was associated with major adverse events or changes in thyroid function test results. Moreover, the doses used in these studies approximately 1,—6, mcg per day are several times higher than the iodine UL of 1, mcg for adults. Doses of this magnitude should only be used under the guidance of a physician [ 2 ]. Radiation-induced thyroid cancer Nuclear accidents can release radioactive iodine into the environment, increasing the risk of thyroid cancer in exposed individuals, especially children [ 77 , 78 ].

Thyroidal uptake of radioactive iodine is higher in people with iodine deficiency than in people with iodine sufficiency. For this reason, iodine-deficient individuals have a particularly high risk of developing radiation-induced thyroid cancer when exposed to radioactive iodine. The FDA has approved potassium iodide as a thyroid-blocking agent to reduce the risk of thyroid cancer in radiation emergencies involving the release of radioactive iodine [ 77 ].

The FDA recommends that exposed people take a daily pharmacological dose 16— mg potassium iodide, depending on age until the risk of significant radiation exposure ends [ 77 , 78 ]. Potassium iodide was widely used in Poland following the Chernobyl accident and childhood thyroid cancer rates did not increase substantially in subsequent years [ 79 ]. In areas where iodide prophylaxis was not used, such as Belarus and Ukraine, where many children were mildly iodine-deficient, the incidence of thyroid cancer sharply increased among children and adolescents [ 77 ].

High intakes of iodine can cause some of the same symptoms as iodine deficiency—including goiter, elevated TSH levels, and hypothyroidism—because excess iodine in susceptible individuals inhibits thyroid hormone synthesis and thereby increases TSH stimulation, which can produce goiter [ 2 , 80 ].

Iodine-induced hyperthyroidism can also result from high iodine intakes, including when iodine is administered to treat iodine deficiency.

Studies have also shown that excessive iodine intakes cause thyroiditis and thyroid papillary cancer [ 2 , 80 ]. Cases of acute iodine poisoning are rare and are usually caused by doses of many grams.

Acute poisoning symptoms include burning of the mouth, throat, and stomach; fever; abdominal pain; nausea; vomiting; diarrhea; weak pulse; and coma [ 2 ]. Responses to excess iodine and the doses required to cause adverse effects vary [ 81 ].

Some people, such as those with autoimmune thyroid disease and iodine deficiency, may experience adverse effects with iodine intakes considered safe for the general population [ 2 , 5 ]. In most people, iodine intakes from foods and supplements are unlikely to exceed the UL [ 2 ].

Long-term intakes above the UL increase the risk of adverse health effects. The ULs do not apply to individuals receiving iodine for medical treatment, but such individuals should be under the care of a physician [ 2 ].

Iodine supplements have the potential to interact with several types of medications. A few examples are provided below. Individuals taking these medications on a regular basis should discuss their iodine intakes with their healthcare providers. Taking high doses of iodine with anti-thyroid medications can have an additive effect [ 81 ] and could cause hypothyroidism. Taking potassium iodide with ACE inhibitors can increase the risk of hyperkalemia elevated blood levels of potassium [ 81 ].

The federal government's — Dietary Guidelines for Americans notes that "Because foods provide an array of nutrients and other components that have benefits for health, nutritional needs should be met primarily through foods. In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more nutrients e. For more information about building a healthy dietary pattern, refer to the Dietary Guidelines for Americans and the U.

Department of Agriculture's MyPlate. This fact sheet by the Office of Dietary Supplements ODS provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers doctor, registered dietitian, pharmacist, etc.

Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice. Updated: March 29, History of changes to this fact sheet. Find ODS on:. Strengthening Knowledge and Understanding of Dietary Supplements. Health Information Health Information. Iodine Fact Sheet for Health Professionals. Health Implications of Perchlorate Ingestion. Institute of Medicine, Food and Nutrition Board.

World Health Organization. Assessment of iodine deficiency disorders and monitoring their elimination. Geneva, Switzerland: WHO, Patrick L. Iodine: deficiency and therapeutic considerations. Altern Med Rev. Iodine deficiency. Endocr Rev. Iodine-deficiency disorders. Prevention and control of iodine deficiency in pregnant and lactating women and in children less than 2-years-old: conclusions and recommendations of the Technical Consultation. Public Health Nutr. Pennington JA, Young B.

Iron, zinc, copper, manganese, selenium, and iodine in foods from the United States Total Diet Study. J Food Compost Anal. Development of databases on iodine in foods and dietary supplements. Nutrients ;10; Iodine database PDF. Department of Agriculture, Beltsville MD. July Food and Drug Administration. Roseland J. Personal Communication. August 13, Composition of Core Foods of the U. Food Supply, Copper, Manganese, Selenium, and Iodine.

J Food Comp Anal. Variability of iodine content in common commercially available edible seaweeds. Fortification Legislation. Iodized salt data. Iodine nutrition: iodine content of iodized salt in the United States.

Environ Sci Technol. Revised April 1, National Institutes of Health. Dietary Supplement Label Database. Bioavailability of seaweed iodine in human beings. Cell Mol Biol Noisy-le-grand. Iodine content of the best-selling United States adult and prenatal multivitamin preparations. Thyroid ; J Expo Sci Environ Epidemiol. Update on dietary intake of perchlorate and iodine from U.

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