10 Foods for Thyroid Health—And 3 To Avoid

Your thyroid needs iodine to work properly and produce enough thyroid hormone for your body's needs, according to the National Institutes of Health (NIH). If you don't get enough iodine, you risk hypothyroidism or a goiter (a thyroid gland that becomes enlarged to compensate for the thyroid hormone shortage, per Medline Plus). Most Americans have no problem getting enough iodine, since table salt is iodized—but if you're on a low-sodium diet (as an increasing number of Americans are for their heart health) or follow a vegan diet (more on that later), then you may need to up your iodine intake from other sources.

Many types of seaweed are chock-full of iodine, but the amount can vary wildly, Mira Ilic, RD, a registered dietician at the Cleveland Clinic, told Health. According to the NIH, the iodine amounts in different seaweed species vary considerably. For example, commercially available seaweeds in whole or sheet form have iodine concentrations ranging from 16 mcg/g to 2,984 mcg/g (the recommended dietary allowance for a non-pregnant or non-lactating person is 150 mcg).

Since seaweed can be especially high in iodine, you shouldn't start eating sushi every day of the week. Too much iodine can be just as harmful to your thyroid as too little by triggering (or worsening) hypothyroidism. To get seaweed's big benefits without going overboard, Cynthia Sass, MPH, RD, and Health's contributing nutrition editor, advised sticking to one fresh seaweed salad per week (in addition to sushi) and steering clear of seaweed teas and supplements.

1. Yogurt

Short of eating a few kelp salads, you probably don't have to worry about getting too much iodine from any other foods. In particular, dairy products contain an average of 85 mcg of iodine per cup, says the NIH.

However, the amount of iodine in dairy products varies. This is partly because livestock are given iodine supplements, and the milking process involves iodine-based cleaners. According to the NIH, when analyzed, samples of nonfat milk were found to contain a range of 38 to 159 mcg per cup.

Plain, low-fat yogurt, or Greek yogurt is a good source —it can make up about 50% of your daily intake of iodine, according to the NIH.

2. Brazil Nuts

According to the NIH, Brazil nuts contain another nutrient that helps regulate thyroid hormones: selenium. Selenium may help stave off long-term thyroid damage in people with thyroid-related problems like Hashimoto's and Graves' disease, according to a 2013 review in the journal Clinical Endocrinology.

Just one kernel contains between 68–91 micrograms. Since the max upper limit of selenium is 400 micrograms a day, don't go overboard. Too much selenium can cause "garlic breath," hair loss, discolored nails, and even heart failure, said Ilic.

3. Milk

Milk and milk products are among the best sources of iodine, according to the NIH. However, plant-based beverages used as milk substitutes, such as soy and almond beverages, contain relatively small amounts of iodine.

Our consumption of dairy has been on the decline for decades. United States Department of Agriculture (USDA) data reveal US per capita fluid cow's milk consumption has been trending downward for over 70 years and continued to decrease at an average rate of 1% per year during the 2000s and at a faster average rate of 2.6% per year during the 2010s.

Drinking 1 cup of low-fat milk will meet about one-third of your daily iodine needs. Another good idea: Opt for a glass of milk fortified with vitamin D. One 2013 study published in the International Journal of Health Sciences found that people with an underactive thyroid (hypothyroidism) were more likely to be deficient in D than their healthier counterparts. (Another honorable dairy mention is cheese, especially cheddar: Just one slice is good for 12 micrograms of iodine and 7 IU of vitamin D.)

4. Chicken and Beef

Zinc is another key nutrient for your thyroid—your body needs it to churn out thyroid hormone. Taking in too little zinc can lead to hypothyroidism, according to a 2013 study published in the International Journal of Trichology. But get this: If you develop hypothyroidism, you can also become deficient in zinc since your thyroid hormones help absorb the mineral, explained Ilic. And when that happens, you may also experience side effects like severe alopecia, an autoimmune condition that attacks hair follicles and makes them fall out in clumps, according to one 2013 report in the International Journal of Trichology.

You probably get enough zinc already (most people in the US do), but if you have a poor diet or a GI disorder that interferes with your ability to absorb zinc, you might be at risk for a deficiency, said Ilic. Meats are a good source, according to the NIH: One 3-ounce serving of beef chuck roast contains 7 milligrams; a 3-ounce beef patty contains 3 milligrams; and a 3-ounce serving of dark chicken meat contains 2.4 milligrams.

5. Fish

Since iodine is found in soils and seawater, fish are another good source of this nutrient, says the American Thyroid Association. Researchers have long known that people who live in remote, mountainous regions without access to the sea are at risk for goiters, as authors of a 2014 study in BMC Public Health wrote.

"The most convincing evidence we have [for thyroid problems] is the absence of adequate nutrition," said Salvatore Caruana, MD, the director of the division of head and neck surgery in the department of otolaryngology-head and neck surgery at Columbia Doctors.

One 3-ounce serving of baked cod contains about 158 micrograms of iodine (enough to satisfy your daily needs if you are not pregnant or lactating), says the NIH. Even fish sticks will provide a healthy amount of iodine at 58 micrograms of iodine in a 3-ounce serving.

6. Shellfish

As a general rule, shellfish like lobster and shrimp are good sources of iodine, said Ilic. Just 3 ounces of shrimp (about 4 or 5 pieces) contains approximately 10% of your recommended intake, according to the NIH.

Bonus: shellfish can also be a good source of zinc, too. Three ounces of Alaskan crab and lobster contain 6.5 and 3.4 milligrams of zinc, respectively, says the NIH.

7. Eggs

One large egg contains about 16% of daily iodine and 20% of daily selenium you need, according to the NIH—making eggs a thyroid superfood.

If you haven't been instructed otherwise by your healthcare provider, eat the whole egg—much of that iodine and selenium is located in the yolk, said Ilic.

8. Berries

The best diet for your thyroid requires more than just iodine, selenium, and vitamin D, said Ilic. Perhaps unsurprisingly, foods high in antioxidants (substances found in certain foods that help fight cell damage) are also good for your thyroid. According to a 2022 study in Biomedicine & Pharmacotherapy, antioxidants can help to manage thyroid dysfunction.

Berries of all kinds are rich in antioxidants, according to Johns Hopkins Medicine, with the "best" berry being black raspberries, a raspberry cousin with a deeper color. Black raspberries provide very high antioxidant levels, fiber, and relatively little natural sugar.

9. Cruciferous Vegetables

Do a little Googling, and you might turn up a page claiming that cruciferous vegetables (think: broccoli, cauliflower, kale, Brussels sprouts) can cause thyroid troubles. The truth is a little murkier. While it's true that these veggies contain compounds called glucosinolates, which might interfere with your body's production of thyroid hormones in high amounts, it's pretty unlikely that they'll harm your thyroid if you're eating normal-size servings.

A 2016 study in Nutritional Reviews found that the amount and type of cruciferous vegetable mattered. Consuming typical serving sizes of raw broccoli, Chinese cabbage, bok choy, broccoli rabe is not likely to impair thyroid function. However, excessive consumption (e.g., >1 kg/d for several months) of raw Russian/Siberian kale, some collards, and Brussels sprouts can decrease iodine uptake into the thyroid and affect thyroid hormone production.

Bottom line: "Cruciferous vegetables like cauliflower and kale are important for a healthy diet and a healthy thyroid," said Ilic. (And besides, if you cook down the foods, you'll release enzymes related to glucosinolates. See? Problem solved.)

10. Soy

The effect of soy on thyroid health has been inconsistent. There are some concerns that soy can negatively impact thyroid function and alter the levels of thyroid hormones, as described by the authors of a 2019 meta-analysis in Nature. After looking at numerous studies, the Nature authors wrote that they found that soy supplementation did not affect the thyroid hormones.

Again, said Ilic, as long as you're eating average amounts of soy, there's no reason to worry it'll hurt your thyroid.

Foods To Limit

Some foods are generally not recommended for thyroid health.

1. Gluten

FYI: This only pertains to people with celiac disease or gluten intolerance.

According to a 2021 review published in Nutrients, celiac disease and autoimmune thyroid diseases such as Hashimoto's thyroiditis and Graves' disease frequently coexist. The review noted accumulating data supports the existence of a significant thyroid-gut-axis—which suggests that gut microorganisms affect not only the immune system and the absorption of micronutrients but also thyroid function.

Though it's not entirely clear whether a gluten-free diet can help treat thyroid disease on its own, if you have been diagnosed with celiac disease, it's important to maintain a strict gluten-free diet to keep symptoms at bay.

2. Processed Foods

If you're thinking about upping your intake of salty, processed foods just to fit more iodine into your diet, think again.

"Manufacturers don't have to use iodized salt in their products," said Ilic. And according to the NIH, they "almost never" do.

The upshot: You may be taking in too much sodium (which can set you up for high blood pressure, then heart disease), minus the iodine.

3. Fast Food

Similar to processed foods, fast food chains also aren't required to use iodized salt in their foods.

According to the American Thyroid Association (ATA), you should avoid restaurant foods since there is no reasonable way to determine which restaurants use iodized salt.

Analysis of the iodine content of commons foods by the United States Department of Agriculture (USDA) found that one fast food hamburger patty contained 3.3 mcg of iodine per 100 g whereas a non fast-food ground beef patty contained 8 mcg of iodine per 100 g.

A Quick Review

Some foods promote thyroid health. For example, foods high in iodine—including seaweed, brazil nuts, fish, and eggs—help your thyroid function effectively. Berries and cruciferous vegetables also support your thyroid. Processed and fast foods are not recommended.

Contact a healthcare provider if you'd like to learn more about how to support your thyroid, and always consult with them before trying supplements. Dietary supplements are minimally regulated by the FDA and may or may not be suitable for you. The effects can also vary from person to person.