Iodized salt image 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.


Iodide helps to:

  • Regulate metabolic rate
  • Regulate growth and development
  • Promotes bone development and protein synthesis

Recommended Intake

Age group Recommended Dietary Allowance [RDA] or Adequate Intake
Upper Limits [UL]
0-6 months 110 Not determinable
7-12 months 130 Not determinable
1-3 years 90 200
4-8 years 90 300
9-13 years 120 600
14-18 years 150 900
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 Iodide

Iodine 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 Iodide

The 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 6 times the RDA) appear to be safe.

Health Implications

When the thyroid gland releases fewer hormones than the body needs, the result is hypothyroidism. Some of the symptoms include:

When more hormones are released than necessary, the result is hyperthyroidism.

Major Food Sources

Iodide 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 1.5 gram 71
Cod, cooked 3 ounces 99
Milk, reduced fat 1 cup 56
Lima beans, cooked ½ cup 8
Banana 1 medium 3

Tips for Increasing Your Iodide Intake

In 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.


American Thyroid Association
Eat Right—American Academy of Nutrition and Dietetics


Dietitians of Canada
The Thyroid Foundation of Canada


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Last reviewed May 2016 by Michael Woods, MD
Last Updated: 6/10/2014

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