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What is Hyperthyroidism? 

Thyroid hormones play a vital role in many body processes. Too much thyroid hormone in your body can cause various symptoms. 

Hyperthyroidism, or overactive thyroid, is a condition in which the thyroid gland in the neck produces excessive thyroid hormone. An example of a common cause of hyperthyroidism is autoimmune thyroid disease (Graves’ disease), in which the body’s immune system attacks healthy thyroid cells by forming anti-thyroid autoantibodies. Overactive thyroid disorder prevalence is about 1% of the U.S. population.

Symptoms of Hyperthyroidism 

According to the American Thyroid Association, symptoms of hyperthyroidism can include:

• Racing heart

• Hand tremors

• Anxiety, nervousness, irritability

• Weight loss despite a normal or sometimes an increased appetite

• Frequent bowel movements or diarrhea

• Fullness in the neck and trouble swallowing

• Increased energy levels

• Heat intolerance or increased sweating

• Menstrual irregularities

• Pain, swelling, bulging of the eyes (thyroid eye disease) for those with autoimmune thyroid disorders

• Insomnia

• Hair loss

Check out our blog to learn 8 signs you may have a thyroid condition. 

Hyperthyroidism is not interchangeable with a similar-sounding condition called HYPOthyroidism, which is an underactive thyroid. Hypothyroidism causes different symptoms from hyperthyroidism. While these two thyroid disorders have overlapping symptoms, they are treated with different medications with close monitoring. In fact,  excessive thyroid hormones used to treat hypothyroidism can even lead to hyperthyroidism. Learn more about hypothyroidism vs. hyperthyroidism.

How Hyperthyroidism Affects Your Metabolism and Dietary Needs

Hyperthyroidism is associated with increased thyroid function. Too much thyroid speeds up the body’s metabolism, increasing resting energy expenditure and weight loss. Weight loss can occur in hyperthyroidism patients even in the presence of a normal or increased appetite. 

Other effects of increased thyroid function include increased hunger and diarrhea (frequent bowel movements). Therefore, there is a complex relationship between hyperthyroidism and weight. Some hyperthyroidism patients may not lose weight, and some may actually experience weight gain if they increase their caloric intake in response to an increased appetite.

It is worth noting that the weight lost due to hyperthyroidism is typically regained once thyroid hormone levels are treated.

The Importance of Managing Your Diet When Living With Hyperthyroidism

There is no specific hyperthyroidism diet that can be used to treat your thyroid disorder or cure hyperthyroidism. Doctors recommend eating a balanced diet with a variety of healthy foods. Generally, eating a healthy diet and nutrient-dense foods supports healthy thyroid function. However, certain foods and food supplements can affect how much hormone the thyroid gland produces. 

Foods That May Worsen Hyperthyroidism

Foods High in Iodine (e.g., Seafood, Seaweed, Iodized Salt)

The following foods are high in iodine and can exacerbate hyperthyroidism symptoms:

• Iodized salt

• Seaweed or kelp

• Fish and shellfish

• Egg yolks

• Dairy products

• Foods containing red dye

• Baked goods with iodate dough conditioners

• Iodine supplements

• Blackstrap molasses

• Carrageenan (seaweed) food additive

The thyroid gland needs iodine to make thyroid hormones. However, if you have hyperthyroidism (an overactive thyroid), eating high-iodine foods or taking an iodine supplement can make the condition worse. Your doctor may ask you to avoid iodine-rich foods and limit your total iodine intake to less than 50 micrograms (mcg) a day because iodine can counteract the benefits of your anti-thyroid medication.

The above is informational only. Speak to your doctor before making any significant changes to your diet.

Caffeinated Beverages

People with hyperthyroidism should avoid or limit their intake of caffeine, which can be found in the following:

• Regular coffee

• Black tea

• Regular sodas

• Energy drinks

• Chocolate

Caffeine can worsen symptoms of hyperthyroidism, such as palpitations, tremors (shaky hands), insomnia, nervousness, and anxiety.

Foods Containing Soy 

People with excess thyroid hormone should consider avoiding foods containing soy, such as:

• Tofu

• Soy milk

• Soy sauce

• Soybean oil

• Edamame

Eating large amounts of soy-based foods can interfere with radioactive iodine treatment for hyperthyroidism and worsen symptoms.

Gluten

A gluten-free diet is recommended for people with celiac disease. Studies have shown that people with celiac disease have a higher incidence of other autoimmune diseases, including autoimmune thyroid diseases.

Celiac disease is an autoimmune disorder of the small bowel. It is caused by an immune reaction to eating gluten, a protein in grains such as wheat, barley, and rye.  

Processed Foods

People with hyperthyroidism should avoid ultra-processed foods such as baked goods and snacks, sodas, sugary breakfast cereals, potato chips, biscuits, ice cream, sausages, instant soups, flavored yogurts, and ready-to-eat meals.

Some studies have shown that ultra-processed foods can increase the risk of subclinical hyperthyroidism.

Recommended Foods for a Hyperthyroidism Diet

Fresh Fruits and Vegetables

Fresh fruits are rich in antioxidants. They fortify the immune system and have anti-inflammatory properties. They are especially beneficial for people with autoimmune thyroid disease, such as Graves’ disease, which is a common cause of hyperthyroidism.

People with hyperthyroidism should eat fresh fruits such as:

• Strawberries

• Blueberries

• Cantaloupe

• Honeydew

• Papaya

• Watermelon

• Oranges

Cruciferous vegetables contain compounds that prevent the uptake of iodine by the thyroid gland. Therefore, they may reduce thyroid hormone production. Examples include: 

• Cabbage

• Cauliflower

• Broccoli

• Brussels sprouts

• Turnips

• Greens (collard greens, mustard greens)

• Arugula

• Kale

• Radish

• Bok choy

Whole Grains, Lean Proteins, and Healthy Fats

People with hyperthyroidism often struggle with weight changes. A healthy, balanced diet that includes whole grains, lean proteins, and healthy fats can help maintain a healthy weight by providing nutrients without extra calories.

Examples of gluten-free whole grains include: 

• Brown rice

• Sorghum

• Buckwheat

• Quinoa

• Oats

• Corn

• Amaranth

Lean proteins recommended for hyperthyroidism include: 

• Chicken breast

• Turkey breast

• Lean beef

• Egg whites

• Beans

• Legumes

• Greek yogurt

Healthy fats include olive oil, nut butters, avocados, nuts, and seeds.

Foods Rich in Calcium and Vitamin D

Thyroid hormones influence bone turnover. People with hyperthyroidism can develop thinning of their bones and low bone mineral density (osteoporosis). Calcium and vitamin D are essential for bone health. Talk to your healthcare provider about taking calcium and vitamin D supplements if your diet lacks these nutrients.

Low-fat dairy, fortified orange juice, broccoli, kale, and bok choy are among foods rich in calcium and vitamin D.

Note: Certain calcium-rich foods are also often iodine-rich and should be avoided, such as fish (tuna and salmon), fortified dairy products, and fortified cereals.

Foods Containing Selenium

Selenium is a micronutrient required for thyroid hormone metabolism. People with overactive thyroids should eat a selenium-rich diet, and selenium supplements are sometimes prescribed for hyperthyroidism. 

Brazil nuts, egg whites, oatmeal, spinach, rice, and baked beans are examples of foods rich in selenium.

Certain selenium-rich foods, such as egg yolks, shrimp, tuna, halibut, cottage cheese, egg yolks, fortified cereals, and pasta, may need to be avoided because they are also high-iodine foods.

Foods Containing Iron

Research suggests a link between low iron levels and thyroid disease. Therefore, it is recommended that people with hyperthyroidism eat iron-rich foods.

Chicken, turkey, beef, pork, spinach, raisins, and dark chocolate are examples of iron-rich foods.

Certain iron-rich foods, such as fish, oysters, sardines, chickpeas, beans, canned meats, and cured meats, also contain high amounts of iodine and should be avoided.

Hyperthyroidism Diet: Frequently Asked Questions 

Are eggs bad for hyperthyroidism?

Egg whites are recommended for people with hyperthyroidism as they are part of a low-iodine diet. However, egg yolks are iodine-rich foods. Your healthcare professional or nutrition counselor can tell you if you should eat whole eggs or egg whites only and how often.

Is oatmeal bad for hyperthyroidism?

No, selenium-rich foods such as oatmeal are not bad for hyperthyroidism. In fact, they may be beneficial for people with this thyroid disorder. 

Is yogurt bad for hyperthyroidism?

No, yogurt is not bad for hyperthyroidism. It is a good source of calcium and can support bone health. People with untreated or severe hyperthyroidism are at risk of decreased bone mineral density and osteoporosis. Eating foods high in calcium and vitamin D is often recommended for such individuals. 

Why is iodine bad for hyperthyroidism?

Iodine is essential for the thyroid gland to make thyroid hormones. Iodine deficiency or excess is rare in healthy people with Western diets. However, a high total iodine intake in people with hyperthyroidism can worsen symptoms. Therefore, doctors sometimes recommend a low-iodine diet to such individuals.

Alcohol and Hyperthyroidism

The link between alcohol and thyroid disorders is not fully understood. There isn’t enough evidence to conclude that drinking alcohol can cause or make hyperthyroidism worse. Studies have shown that alcohol can damage thyroid cells and suppress thyroid function. 

Alcohol is known to be a causative factor in over 200 health conditions, according to the Pan American Health Organization. While there is no direct association between alcohol consumption and thyroid cancer, you should avoid drinking excessive amounts of alcohol to promote your overall health. 

Can Diet and Lifestyle Changes Treat Hyperthyroidism?

There are no specific foods or supplements that can improve thyroid function or cure hyperthyroidism. However, certain foods and nutrients can affect the production of thyroid hormones and influence thyroid function. 

A low-iodine diet is typically recommended for people with hyperthyroidism. You should work with your healthcare provider and dietician to develop a healthy eating plan. This will ensure you get all the nutrients your body needs while supporting thyroid health.

Lifestyle Modifications as a Complementary Treatment

Eating a healthy diet, regular exercise, and managing stress complement hyperthyroidism treatment. These measures also promote overall well-being and, as a result, provide long-term benefits for both physical and mental health.

The Necessity of Medication Alongside Dietary Adjustments

Anti-thyroid drugs such as methimazole and propylthiouracil are used to treat hyperthyroidism by reducing thyroid hormone formation. 

Methimazole absorption in your stomach can be affected by the presence of food. Therefore, to ensure stable thyroid levels, you should take this medication consistently— either always on an empty stomach or always with meals. Find out why some medications must be taken with food.

Along with dietary adjustments such as eating low-iodine foods, taking your prescribed medication for thyroid issues is important. Following your healthcare provider’s treatment plan will help keep your thyroid hormone levels in the normal range and control symptoms of hyperthyroidism. 

It is also important to keep all laboratory appointments during treatment for your thyroid disease. Your provider will periodically order blood work for thyroid testing, including thyroid stimulating hormone (TSH) and thyroid hormone levels, and adjust your medication dose based on the results. 

Always check with your healthcare provider before taking any new medications or herbal supplements. Drug interactions between medications can make treatment for hyperthyroidism less effective or increase your risk of side effects. If you are deficient in any of these nutrients, your doctor can recommend specific dietary supplements, such as calcium, vitamin D, iron, or zinc supplementation.

Check out: What Are Some Signs My Thyroid Medication Is Not Working?

Additional Treatment Options for Hyperthyroidism

Radioactive Iodine Therapy and Its Dietary Implications

If you are prescribed radioactive iodine treatment, your healthcare provider may recommend eating a low-iodine diet during the treatment. The reason for this is that the presence of too much iodine can make the treatment less effective. Specifically, an excessive iodine level in your body can cause your thyroid gland to use the ingested iodine instead of the radioactive iodine. 

Keep in mind that a low iodine diet means eating less than 50 micrograms (mcg) of iodine per day. 

Surgical Options and Their Impact on Nutrition

There are no specific dietary restrictions after thyroidectomy (thyroid removal surgery). You should aim to eat a balanced, healthy diet. 

Swallowing can be difficult in the days immediately following your surgery. You may need to start by eating soft foods such as gelatin, mashed potatoes, pudding, apple sauce, yogurt, and drinking fluids to stay hydrated. Also, it’s a good idea to avoid hard, spicy, acidic, fried, or sticky foods that can be difficult to swallow.

Conclusion: Tailoring Your Diet for Hyperthyroidism Management 

People with a diagnosis of hyperthyroidism may need to avoid high-iodine foods, soy-based foods, gluten, caffeine, and ultra-processed foods. Always follow the dietary advice from your doctor or healthcare team.

They should eat more fresh fruits and vegetables, lean proteins, whole grains, healthy fats, and foods rich in iron, calcium, vitamin D, and selenium.

Work with Healthcare Providers for a Personalized Diet Plan

Developing a healthy eating plan for hyperthyroidism can be confusing. For example, high-iron foods are recommended, but these foods can also increase your total iodine intake, which can worsen hyperthyroidism. It is, therefore, a good idea to work with your healthcare provider or a trained nutritionist such as a registered dietician. They can develop a personalized diet plan that supports thyroid function and considers your personal preferences. 

Talk to your healthcare provider if you need a referral to establish care with a dietitian on your healthcare team.