Your body needs iodine, a mineral, to work properly. The thyroid gland, for example, uses iodine to make the thyroid hormone thyroxin. Most iodine is in the form of iodide. These terms are often used interchangeably.
FunctionsIodide helps to:
- Regulate metabolic rate
- Regulate growth and development
- Promotes bone and protein synthesis
|Age group|| Recommended Dietary Allowance [RDA] or Adaquate Intake |
| Upper Limits [UL] |
|0-6 months||110||Not determinable|
|7-12 months||130||Not determinable|
|19 years and older||150||1,100|
|Pregnancy (18 or younger)||220||900|
|Pregnancy (19-50 years)||220||1,100|
|Lactation (18 or younger)||290||900|
|Lactation (19-50 years)||290||1,100|
Too Little IodideIodine deficiency can cause a range of problems, including mental retardation, hypothyroidism, goiter , and other growth and developmental problems. Thyroid enlargement (goiter) is one of the early signs of iodine deficiency. Not getting enough iodine is especially harmful for the developing brain, such as during pregnancy and in infants. This is why the American Thyroid Association recommends that pregnant and breastfeeding women take a daily prenatal supplement that contains iodine. Goiter is not as common as it once was in the US because of iodized salt however, iodide deficiency is a major public health issue in many regions around the world.If eaten in large quantities, some foods, like raw turnips and rutabagas, have chemicals that can cause goiters and inhibit thyroid gland functions. These chemicals, called goitrogens, are destroyed when the foods are cooked, so problems are uncommon.
Too Much IodideThe thyroid can also become enlarged if you have too much iodide in your diet, though this is rare in the US. This toxic goiter is caused by elevated concentrations of thyroid stimulating hormone (TSH). This is often seen in people who eat a lot of seaweed, which can add a significant amount of iodide to the diet. Iodide levels up to 1 milligram (more than six times the RDA) appear to be safe.
Health ImplicationsWhen the thyroid gland releases fewer hormones than the body needs, the result is hypothyroidism . Some of the symptoms include:
- Coarse, brittle hair; hair loss
- Facial puffiness
- Dry skin
- Swollen hands or feet
- Cold intolerance
- Weight gain
- Achy feeling all over
- Depression and irritability
- Menstrual abnormalities or infertility
- Heat intolerance
- Enlarged thyroid gland (goiter)
- Heart palpitations
- Increased sweating
- Nervousness, irritability
- Redness, swelling, and protrusion of the eyes
- Shortness of breath
- Increased number of bowel movements
- Irregular or no menstrual period
Major Food SourcesIodide is found naturally in food grown in or near coastal seas. Seafood is naturally high in iodide, as are plants grown near the sea. Molasses and iodized salt are also good sources. Most people get plenty of iodide from the iodized salt in their diets, since only ½ teaspoon of iodized salt provides enough iodide to reach an adult's RDA for the day. The sea salt found in health food stores is generally not a good source because iodide is lost during processing.
|Food||Serving Size|| Iodide content |
|Table salt, iodized||1 gram||77|
|Cod, cooked||3 ounces||99|
|Potato, cooked, peeled||1 medium||60|
|Lima beans, cooked||½ cup||8|
Tips for Increasing Your Iodide IntakeIn general, there is little need to increase your iodide intake. Most people in the US get plenty from their diets, much of this coming from iodized salt. But if you use sea salt (or another type of salt) that does not have iodide, you can get the mineral from seafood or other sources. This is also true if you are on a low-sodium diet. Talk to your doctor if you are concerned about how much iodide you are getting.
EatRight.org - American Academy of Nutrition and Dietetics
Thyroid.org - American Thyroid Association
Dietitians of Canada
Thyroid.ca - The Thyroid Foundation of Canada
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Iodine. Oregon State University Linus Pauling Institute website. Available at: http://lpi.oregonstate.edu/infocenter/minerals/iodine. Updated March 2010. Accessed June 10, 2014.
Iodine deficiency. American Thyroid Association website. Available at: http://www.thyroid.org/iodine-deficiency. Accessed June 10, 2014.
Iodine fact sheet for health professionals. Office of Dietary Supplements website. Available at: http://ods.od.nih.gov/factsheets/Iodine-HealthProfessional. Updated June 24, 2011. Accessed June 10, 2014.
Papillary thyroid cancer. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated June 2, 2014. Accessed June 10, 2014.
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- Reviewer: Michael Woods, MD
- Review Date: 06/2014
- Update Date: 06/10/2014