Thanks to the mineral levels in the food supply, iodine deficiency in the United States is rare. Even then, knowing how your body can signal that it needs more iodine in your diet is always something to learn. For that reason, we spoke with a registered dietitian nutritionist to explain how your body can signal that it needs more iodine with a list of top food sources.
What to know about iodine
Before we get into iodine deficiency, let’s first cover what iodine is and why it’s important for our thyroid health. “Iodine is a trace mineral found naturally in foods like fish and seaweed, essential for the production of thyroid hormones,” says Elise Harlow, MS, RDN, a California-based registered dietitian nutritionist and founder of Flourished Table. “Iodine is [also] involved in every cell in our body and necessary for normal cell function, thyroid function, and fetal and infant development.” Our bodies cannot make iodine on their own, so getting it early is essential. through dietary sources.
The Recommended Dietary Allowance (RDA) for iodine for the general public is 150 mcg, 220 mcg for pregnant women, and 290 mcg for breastfeeding women. The RDA for pregnant and lactating women requires more iodine due to increased maternal thyroid production, increased renal iodine losses, and transfer of iodine to the infant.
“It’s relatively easy to meet your iodine needs by eating iodine-rich foods, but there are certain instances where you may be at higher risk for iodine deficiency,” says Harlow. “For example, if you are vegan or vegetarian or remove iodized salt from your seasoning rotation, then this may reduce your overall iodine intake.”
In those cases, you can always ask your GP to test you for iodine deficiency with a urine sample. However, Harlow says this isn’t something to stress about, as iodine deficiency is rare, especially if you’re already taking a multivitamin that contains iodine.
The most common iodine deficiency symptoms to discuss with a doctor
“The first sign of iodine deficiency may be suboptimal thyroid function, where the thyroid begins to produce less thyroid hormone, but not to the point where doctors would diagnose clinical hypothyroidism and prescribe medication,” says Harlow. “Most functional and integrative clinicians will recognize suboptimal thyroid function and perform further testing to determine if iodine deficiency may be contributing to poor thyroid function.”
If left untreated, this can lead to clinical hypothyroidism, a condition where the thyroid gland doesn’t produce enough thyroid hormones, and then goiter, which is an enlargement of the thyroid gland that can look like a swelling in the neck area. “When there is not enough iodine [in the body]your thyroid can’t make the hormones that are used for many different functions, causing it to enlarge in an attempt to seek out more iodine so it can make thyroid hormone,” says Harlow. This can often look like a swelling in the neck or feeling of tightness in the throat area.
“Other examples of iodine deficiency are pregnancy-related problems, such as birth defects and preterm labor,” says Harlow. She recommends asking her GP to get tested for iodine deficiency if she experiences swelling in her neck or if she’s just curious about thyroid function.
6 food sources of iodine
Luckily, Harlow’s list of iodine-rich foods she recommends adding to your diet is packed with delicious ingredients. (Just keep in mind as you read them that the intake percentages are based on the RDA for the general public and not for women who are pregnant or nursing.)
1. Iodized salt: The most common way to consume iodine is through iodized salt, a version of salt created in 1924 to prevent goiter and iodine deficiency. “In a teaspoon of iodized salt, there’s 400 mcg of potassium iodide, which is the carrier for iodine,” says Harlow. “However, it is important to note that iodine content is reduced by 50 percent one to two months after exposure to air.”
2. Algae: Seaweed not only contains fiber linked to the benefits of stimulating the intestine, but is also considered a great source of iodine. “Two tablespoons of seaweed is about 115 mcg of iodine, which is about 80 percent of the RDA,” says Harlow.
3. OystersOysters: Oysters may not be to everyone’s taste, but they offer about 90 mcg of iodine in three ounces of oysters, which is about 60 percent of daily needs.
4. Cod: There is 160 mcg of iodine in three ounces of cod, which is just over 100 percent of the daily needs.
5. Greek yogurt: Greek yogurt is a great way to increase your iodine intake, especially if you’re not a fan of seafood. “Three cups of Greek yogurt have 90 mcg of iodine, or 60 percent of your daily needs,” says Harlow. You can have Greek yogurt with fruit and your favorite granola as a snack or morning breakfast.
6. EggsNote: One egg contains 25 mcg of iodine (20 percent of the RDA), so if you use two eggs for your morning omelette, you’re already getting 50 grams of iodine alone.
The bottom line? Iodine deficiency is probably not something to stress about, especially if you’re already consuming several foods from the list above. If iodine deficiency is of concern to you, you can always request that your primary care physician do a urine test to look for deficiency. Harlow also recommends talking to a doctor or dietitian about taking a multivitamin to fill in nutrient gaps, if you’re not already taking one.