Foods to Eat and Avoid for Hyperthyroidism
Medically reviewed by Kelly Wood, MD
There is no specific hyperthyroidism diet. However, there are numerous minerals, vitamins, and nutrients you can eat to help you balance your thyroid hormones. B vitamins, selenium, and iron are just a few of them.
As part of your treatment plan, you may also need to limit your intake of iodine, soy, and other foods that could aggravate your symptoms. Adopting a hyperthyroidism diet is important for keeping your symptoms under control and limiting potentially harmful medication interactions.
This article discusses the dos and don'ts of a hyperthyroidism diet. It explains what to eat to improve thyroid health along with the foods to avoid.
Verywell / Mayya Agapova
How Food Impacts Hyperthyroidism
Thyroid function is primarily regulated by the minerals iodine and selenium with the support of vitamins A, E, D, and B. Other micronutrients, including zinc, copper, and iron, are essential for healthy thyroid function.
With that being said, taking too much of these vitamins and minerals by way of supplements can work against you. For example, supplemental iodine is known to cause flare-ups in people with Hashimoto's disease because iodine stimulates autoimmune antibodies.
Although you cannot cure hyperthyroidism with diet alone, adding or eliminating certain foods from your diet can help balance your thyroid hormones and manage your hyperthyroidism symptoms.
Takeaway
As with any therapy, make sure to work with your healthcare provider before making major changes to your diet or adding any supplements to your daily routine.
Foods to Eat for Hyperthyroidism
Several nutrients are vital for optimal thyroid health. Nonetheless, the goal of a hyperthyroidism diet is not to consume them in excess, but rather to get adequate amounts of them in your diet to avoid harmful deficiencies.
Meeting the recommended daily allowance (RDA) for the following nutrients can help improve thyroid functioning and prevent disease progression.
Related: What to Know About Hyperthyroidism Treatment
Iron
When your thyroid hormone levels are too high, your body cannot metabolize iron normally. For some people, this can result in iron deficiency or anemia.
Iron deficiency due to hyperthyroidism typically goes away with hyperthyroidism treatment. If it doesn't, your healthcare provider may ask you to eat more iron-rich foods or take a daily iron supplement.
Otherwise, you should aim to consume the RDA for iron. The RDA for adults 19 to 50 years is 8 milligrams (mg) for men and 18 mg for women.
Iron-rich foods that can contribute to your RDA include:
Lean meat
Spinach
Sweet potatoes
String beans
Whole wheat bread
Strawberries
Prunes
Beans
Lentils
Takeaway
Iron may interfere with the absorption of your thyroid medication. Talk to your doctor before adding an iron supplement to your diet plan.
Related: Iron Supplements: Side Effects, Uses, and More
B Vitamins
Vitamin B1 (thiamine) is critical for people with hyperthyroidism because high amounts of thyroid hormones in the blood cause thiamine stores to deplete faster. This puts people with hyperthyroidism at an increased risk for thiamine deficiency.
Other B vitamins that are important include vitamins B12 (cobalamin), B6 (pyridoxine), B3 (niacin), and B2 (riboflavin). If your healthcare provider finds that you have a vitamin B deficiency, you may need to take a vitamin B complex supplement.
Otherwise, try to eat more foods that contain vitamin B, such as:
Liver
Fish
Fortified cereals
Chickpeas
Bananas
Dark leafy greens
Takeaway
Biotin, a B vitamin, may interfere with thyroid lab tests, resulting in falsely high levels of T4 and T3 and falsely low levels of thyroid stimulating hormone (TSH). Tell your healthcare provider if you are taking a supplement that contains biotin. You may need to stop taking it for three to five days before thyroid testing to avoid false results.
Related: The 6 Best B-Complex Supplements of 2023
Selenium
The thyroid contains more selenium per gram of tissue than any other organ in the body. On top of that, selenium is largely responsible for regulating thyroid hormone levels.
Research shows that selenium deficiency is associated with Graves' disease—the number one cause of hyperthyroidism in adults. Selenium supplementation has been found to improve thyroid function in adults with Graves' disease and delay the disease's progression.
Let your healthcare provider determine if you need a selenium supplement. There are plenty of foods that contain selenium as well, including:
Brazil nuts
Tuna, halibut, sardines
Organ meats
Ham
Cottage cheese
Oatmeal
Whole grains and cereals
Poultry
Fish
Takeaway
Brazil nuts contain extremely high amounts of selenium at 68 to 91 micrograms (mcg) per nut. Eating Brazil nuts regularly can lead to selenium toxicity. Signs of selenium toxicity include stomach and breathing problems, hair loss, tremors, and lightheadedness. In rare cases, selenium toxicity can be life-threatening.
The RDA for selenium is 400 mcg for both males and females ages 19 years and above. That equates to about four brazil nuts per day.
Zinc
Your body needs zinc in order to produce and metabolize thyroid hormone. Zinc deficiency has been found to worsen hyperthyroidism, while zinc supplementation has been found to improve it.
The RDA for zinc is 11 mg for men and 8 mg for women ages 19 and above. Foods that can help you reach the RDA include:
Oysters
Meat, fish, and poultry
Crab and lobsters
Fortified breakfast cereals
Beans
Nuts
Whole grains
Dairy products
Takeaway
Taking too much zinc can result in negative side effects, including nausea, dizziness, headaches, upset stomach, and hair loss, so it's important to only take a zinc supplement if your healthcare provider finds it necessary.
Copper
Another trace element with an important role in thyroid hormone production and absorption is copper.
In addition to regulating thyroid function, copper helps control calcium levels in the blood. This is critical, since about 20% of people with hyperthyroidism develop mild to moderate hypercalcemia (abnormally high blood calcium levels), placing them at an increased risk for osteoporosis.
For adults 19 years and above, the RDA for copper is 900 mcg per day. Copper deficiency is rare, but you should still aim to meet the RDA by eating copper-rich foods.
Good dietary sources of copper include:
Oysters and crab
Salmon
Dark unsweetened chocolate
Cashews
Sunflower and sesame seeds
Chickpeas
Potatoes
Spinach
Vitamin D
Vitamin D deficiency is linked to a number of autoimmune diseases, including Graves' disease, and research shows that vitamin D3 (cholecalciferol) supplementation can help people with Graves' disease improve their condition.
Furthermore, several studies have found that vitamin D3 supplementation alone may prevent thyroid disease and thyroid cancer.
The RDA for vitamin D is 15 mcg for adults ages 19 and above. It can be difficult to meet the RDA for vitamin D through diet alone, so many people choose to take vitamin D supplements.
Great food sources of vitamin D include:
Cod liver oil
Salmon
Swordish
Tuna fish
Fortified orange juice and milk
Fortified cereals
Sardines
Antioxidants
Grave's disease is an autoimmune condition in which antibodies that mimic TSH bind to the TSH receptor and overstimulate the thyroid gland.
Graves' disease, and thyroid diseases in general, are closely linked to oxidative stress, in which circulating free radicals in the body damage cells and tissues.
Antioxidants are beneficial for people with hyperthyroidism because they fortify the immune system and fight against cell damage due to free radicals.
The best way to supplement your diet with antioxidants is to eat plenty of colorful fruits and vegetables. Antioxidant powerhouses include:
Strawberries
Blueberries
Cantaloupe
Leafy greens
Honeydew
Papaya
Avocados
Oranges
Watermelon
Foods to Avoid for Hyperthyroidism
Sometimes, foods that are generally considered healthy contain nutrients that, when consumed in excess, can worsen your hyperthyroidism symptoms, interfere with your medications, or cause inaccuracies in your thyroid test results.
Play it safe by consulting with your healthcare provider before making major changes to your diet. Your provider can help you determine how much or how little of any food you should eat as part of your hyperthyroidism diet.
Iodine
One such nutrient that should be avoided in excess is iodine. Although iodine plays a major role in thyroid hormone regulation, excessive amounts of it can actually cause hypothyroidism.
Never take iodine supplements without your healthcare provider's approval. Iodine supplementation is only needed if you have an iodine deficiency—something that is rare in developed countries.
It's okay to eat small amounts of iodine-containing foods here and there, but take care to avoid eating them in excess. Foods with iodine include:
Seaweed, such as nori, kelp, kombu, and wakame
Fish and shellfish, such as cod, canned tuna, oysters, and shrimp
Iodized table salts
Dairy, including milk, cheese, and yogurt
Beef liver
Chicken
Eggs
Takeaway
Egg yolks are higher in iodine than egg whites. Choosing just the whites will help you keep your total iodine intake down if recommended.
Soy
Soy is considered a goitrogenic food, meaning that eating too much of it on a regular basis can have a negative effect on your thyroid health.
Goitrogens disrupt your body's ability to produce and release thyroid hormone and can worsen iodine deficiency. In large quantities, goitrogens can cause an enlarged thyroid, known as a goiter.
Soy also reduces the absorption of thyroid hormone from medication. If you are taking thyroid medication or have an underactive thyroid, it's important to avoid eating soy and other goitrogenic foods in large quantities.
If you are unsure about how much soy is safe for you to eat, ask your healthcare provider. Soy products include:
Tofu
Soy milk
Edamame
Soy milk and sprouts
Miso
Tempeh
Natto
Soy sauce
Soy-based infant formulas
Related: Can You Eat Soy If You Have a Thyroid Condition?
Allergenic Foods
Food allergies can worsen the symptoms of hyperthyroidism. Your healthcare provider may want to test you for common allergens like dairy, gluten (from wheat), corn, food additives, and preservatives to make sure allergies aren’t contributing to your condition.
Cruciferous Vegetables
Kale, cauliflower, bok choy, broccoli, and Brussels sprouts are cruciferous vegetables from the Brassicaceae family. When consumed raw and in high volume, goitrogenic compounds in these vegetables may interfere with thyroid function.
Cooking cruciferous vegetables and consuming them in moderation helps avoid potential problems with hyperthyroidism.
Sugary Foods
Having thyroid disease increases your risk of type 2 diabetes, and people with diabetes are more likely to have hypothyroidism than people who don't.
Exactly how the two endocrine diseases are linked is not fully understood, but it's clear to researchers that having both conditions at the same time makes treating either one of them more difficult.
Although a sweet treat every now and then is unlikely to be harmful, it's best to avoid foods and drinks that contain added sugar. This includes candy, molasses, cakes and pastries, syrups, soft drinks, and other sugar-sweetened drinks.
Related: Sugar, Artificial Sweeteners, and Thyroid Problems
Caffeine
Caffeine can intensify several symptoms of Graves' disease, including anxiety, nervousness, and rapid heart rate.
Although some people tolerate caffeine better than others, it's a good idea to avoid caffeinated drinks like coffee and tea, as well as ginseng, yerba mate, and other stimulants commonly found in energy drinks.
Related: How Coffee Interferes With Synthroid (Levothyroxine)
Summary
If you have thyroid issues, it’s crucial to keep up with lab work and identify nutrient deficiencies that may be contributing to your condition. In many cases, nutrient deficiencies can be corrected by adding particular foods to your diet.
Certain foods, like whole wheats, fresh fruits and vegetables, and lentils, contain valuable nutrients that can help keep your thyroid hormone levels balanced and improve thyroid function. Others, like raw cruciferous vegetables, should be limited or avoided, depending on your healthcare provider's recommendation.
Ask your healthcare provider before starting any supplements (including multivitamins and herbal supplements), especially if you have borderline thyroid issues or take thyroid medication.
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