wiki team
- Sep 9, 2022
- 5 min read

What Is Iodine & How Do You Know If You're Deficient?

The thyroid is a gland in the neck that produces hormones that help regulate metabolism and growth. The thyroid uses iodine as a building block for these hormones, so your body must have enough iodine. Many factors affect your thyroid health, including stress, prescription medication, sleep, and blood pressure. However, one of the most critical significant factors is iodine deficiency. Iodine is required for healthy thyroid function, but many people are deficient in it. If you have questions about how to increase your iodine intake or if you may be low in iodine, your doctor is the best person to talk to.

What is iodine?

Iodine is a mineral naturally found in some foods, including iodized salt. It's also a part of the thyroid hormones thyroxine and triiodothyronine, which help regulate metabolism, growth, and development. Inadequate iodine intake can lead to thyroid problems such as hypothyroidism or hyperthyroidism.

Iodine deficiency and its health effects

You may be wondering: what is iodine, and how do you know if you're deficient? Iodine is a mineral that is essential for healthy thyroid function. If deficient in this vital nutrient, it can cause hypothyroidism (a condition where your thyroid gland does not produce enough hormones). Hypothyroidism can result in poor metabolism, weight gain/loss, fatigue, and hair loss.

If your doctor suspects that you have an iodine deficiency, they will likely give you a test called the Quantitative Thyroid-Stimulating Hormone (QTHS) test. This test measures the amount of TSH in your bloodstream; higher than normal levels indicate an underactive thyroid gland or hypothyroidism.

How much iodine do we need?

The RDI for iodine is 150 micrograms per day for adults.

Simple iodine sources you can use to get your daily dose of this nutrient includes:

Seaweed, such as kelp and nori (dried sheets of seaweed)
Fish and seafood like oysters, mussels, shrimp, and cod liver oil. Be careful if you have a seafood allergy!
Apple cider vinegar that's been fermented long enough to extract its nutrients from the apples (check out our guide to learn how). Check out these recipes for making your own ACV too!

Iodine deficiency and pregnancy

You can become deficient in iodine while you are pregnant. Iodine deficiency has been linked to low birth weight, premature birth, and miscarriage. It may also cause the thyroid gland to grow too big and become overactive (hyperthyroidism) or shrink and become underactive (hypothyroidism).

Are there any risks of taking too much iodine?

In large doses, iodine can be toxic and cause serious health problems. However, this is not the case when you get enough from your diet.

In an article published in the International Journal of Endocrinology & Metabolism in 2012, researchers found that people who consumed more than 1 milligram of iodine per kilogram of body weight daily experienced side effects such as goiter (a swelling of your thyroid gland), hypothyroidism and hyperthyroidism. If you take too much iodine as a supplement—say 2–4 mg/kg of body weight for several months—you may experience these side effects too.

Iodine is safe at normal levels and should not be taken except under the direction of a doctor if you have any thyroid disorders or are pregnant or breastfeeding.

Do you need an iodine supplement?

If you're deficient, you may need to take a supplement. But how do you know if your thyroid is doing okay?

Your thyroid gland produces hormones that control your metabolism. If it's not working correctly, this can mess with everything from weight gain to energy levels and fertility. And if you're pregnant, iodine deficiency can cause serious health problems for both mother and baby (as well as premature birth). Because of all this, doctors recommend getting enough iodine in your diet so that the thyroid functions normally—and so does every other part of your body. The problem is that people don't get enough iodine naturally from food alone; studies show that only 27% of adults in North America have an adequate mineral intake through diet alone (1). So unless there's some significant disaster involving widespread food shortages or radiation poisoning affecting the environment—which seems pretty unlikely—you should probably take a supplement unless there's a specific reason not (like high radiation exposure).

There are two main kinds of supplemental forms: potassium iodide and kelp tablets (also called "organic" or "natural"). Potassium iodide has been used since ancient times because it's easier on babies' immature digestive systems compared with kelp supplements; however, some experts say that only about 10% gets absorbed into our bodies when taken this way because our stomachs aren't very good at breaking down large molecules like these into smaller parts which we can absorb more efficiently."

Where can you find high levels of iodine naturally?

The easiest way to get your daily dose of iodine is by consuming foods that are naturally high in this nutrient. Here are some of the best sources:

Seaweed: Seaweed, like kelp and nori, contains an abundance of iodine. Kelp supplements can also be purchased as a convenient way to increase your intake without having to eat seaweed on its own!
Fish: Seafood like tuna, salmon, cod, and scallops are rich in this mineral.
Sea salt: Many brands of sea salt contain added iodine—but make sure it's labeled "iodized" before you purchase it! Some salt has been processed with potassium instead, which may lead to the deficiency if not taken care of properly (and fortunately, we have a guide on how to do just that). For ease, though, you might want to go with a traditional brand such as Morton's iodized table salt or Diamond Crystal kosher iodized sea salts; both come in handy pre-flavored varieties as well, such as garlic flavor for extra flavor perks without any additional effort required from you.

Many factors affect your thyroid health, including stress, prescription medication, sleep, and blood pressure. However, one of the most critical significant factors is iodine deficiency. Iodine is required for healthy thyroid function, but many people are deficient in it. If you have questions about how to increase your iodine intake or if you may be low in iodine, your doctor is the best person to talk to.