The best diet for hyperthyroidism

Hyperthyroidism occurs when your thyroid gland, the butterfly-shaped gland near the front of your neck, secretes too much thyroid hormone. Thyroid hormones are responsible for keeping your metabolism in check. When you have an overactive thyroid, you may experience symptoms such as unexplained weight loss, increased appetite, rapid heart rate, frequent bowel movements, and persistent nervousness. These are all signs your metabolism is out of whack.

There are several causes, but the autoimmune condition Graves’ disease is the most common cause of hyperthyroidism. “Graves’ disease is when the immune system makes antibodies that stimulate the thyroid to pour out excess thyroid hormone,” says Gillian Goddard, MD, an endocrinologist in New York. Other causes of hyperthyroidism include thyroid nodules or goiter, thyroiditis, excess iodine in the diet, cancer medications, radiation, trauma, and certain medications that are used to treat hypothyroidism (underactive thyroid).

If an overactive thyroid gland is untreated, there can be serious health consequences, according to the National Institutes of Health. These can include blood clots, stroke, heart failure, and other heart problems, an eye disease called Graves’ ophthalmopathy, thinning bones, osteoporosis, muscle weakness, and menstrual cycle or fertility issues. Luckily, there are treatments that can help—from lifestyle changes to medication.

Your healthcare provider may recommend adjustments to your diet as part of your treatment plan. While certain foods are good for thyroid dysregulation, there are also foods to avoid with hyperthyroidism. Here, experts discuss thyroid healing foods and the best diet for hyperthyroidism and Graves’ disease.

What is the best hyperthyroidism diet?

The best diet for hyperthyroidism is a high calorie, nutrient-dense eating plan. “Any diet plan avoiding whole food groups and carbohydrates would not be recommended,” says Jamie Feit, MS, a registered dietitian and expert at testing.com. “Therefore, I would not recommend keto, paleo, vegan, or plant paradox. DASH and Mediterranean diets might be okay, but the goal of hyperthyroidism is to be on a high calorie diet containing nutrient-dense foods, not a weight loss diet.”

Dr. Goddard adds: “When hyperthyroidism is not yet treated, people tend to have an increase in appetite and lose weight [despite eating more]. But when we bring the thyroid hormone levels back down to normal, people will often regain the weight they lost and more.” In patients where weight gain is a concern, Dr. Goddard recommends a low carbohydrate diet rich in veggies and healthy fats. 

There are a few other considerations around Graves’ disease diets. For example, very high iodine foods like seaweed and kelp could make hyperthyroidism worse. 

7 foods for hyperthyroidism

People with hyperthyroidism should aim for a healthy diet that includes plenty of fruits and vegetables, low-fat dairy products, whole grains, lean protein sources, and unsaturated fats in order to promote thyroid health. “It is important to consume enough carbohydrates to prevent low blood sugar episodes,” Feit says.

When thyroid disease is caused by Graves’ disease, which is an autoimmune disorder, Dr. Goddard says an autoimmune protocol (AIP) diet might be beneficial, though there is insufficient research data to fully recommend the diet. The AIP diet focuses on whole foods and eliminates sugar to avoid spiking blood sugar. The following are included:

1. Leafy greens 

Leafy greens such as spinach are an important source of calcium. This can help people with hyperthyroidism because excess thyroid hormone production can lead to breakdown of bones and an increased risk of osteoporosis.

2. Fish rich in omega-3 fatty acids

Fatty fish like salmon are an important source of vitamin D, which helps improve your body’s calcium absorption. This helps to decrease risk of osteoporosis. Research indicates that omega-3 fatty acids contribute to improved liver function, which can be negatively impacted by thyroid dysregulation.

3. Fermented foods

Foods such as kimchi, kombucha, kefir, and sauerkraut contain probiotics. These help enhance gut health and may help regulate thyroid function. “How gut health and thyroid health are connected is poorly understood,” Dr. Goddard says. “But insofar as gut health is also related to inflammation, we think perhaps that is the connection.”

4. Lean meats and liver

These iron rich foods help increase your iron levels. Research has linked low levels of iron  to hyperthyroidism. 

5. Fresh fruit

Fresh fruit can be eaten in moderation, at a maximum of 10-40 grams of fructose per day (one to two pieces of fruit). Apples, avocado, and berries are good options for those with hyperthyroidism following an AIP diet because they are low-glycemic and will not raise blood sugar levels.

6. Olive oil

Olive oil can reduce inflammation in the body and improve thyroid function. “Often hyperthyroidism is autoimmune, and any autoimmune disorder may be triggered because the immune system is responding inappropriately to inflammation,” Dr. Goddard says. “Reducing inflammation in general may decrease the autoimmunity.” 

RELATED: The best diet for inflammation

7. Brazil nuts

Selenium has been shown to have possible benefits in autoimmune thyroid diseases like Graves’ disease. It is found in brazil nuts in high concentrations; just two to three brazil nuts can provide the recommended 200 mcg of selenium per day.

4 foods to avoid with hyperthyroidism

Experts recommend avoiding the following foods if you have hyperthyroidism.

1. Seaweed 

Although iodine supplements and consumption may be beneficial to people with hypothyroidism, a low-iodine diet is recommended because too much iodine can worsen hyperthyroidism, according to the American Thyroid Association. Replacing iodized table salt with Himalayan or sea salt can also help limit iodine consumption.

RELATED: How to treat iodine deficiency

2. Cruciferous vegetables 

Goitrogens, which are substances found in cruciferous vegetables, legumes, and some root vegetables, are thyroid hormone disruptors. They inhibit the thyroid gland to uptake iodine, and increase auto-immune thyroid disease. “They can be problematic if not cooked and not consumed as only part of a healthy diet,” Feit explains. For this reason, foods like cauliflower, broccoli, Brussels sprouts, kale, and cabbage are not recommended for hyperthyroidism. 

3. Gluten

There is some evidence that gluten can cause inflammation, which damages thyroid health. While more research is required, following a gluten-free diet may help to improve symptoms. That means avoiding foods that contain wheat, barley, malt, and rye.

4. Coffee 

Caffeine should be avoided as well, because it is a stimulant and can worsen fast heart rate and heart palpitations, Feit says. It also may affect absorption of medication to treat hyperthyroidism.

Does fasting help hyperthyroidism?

Fasting is absolutely not helpful for hyperthyroidism, says Feit. While it may not cause problems for some people with mild symptoms, for others it could lead to dehydration and diarrhea. Instead, a healthy diet with frequent snacks is recommended. Be mindful of what you’re eating, and include complex carbohydrates such as whole grain bread, brown rice, quinoa, barely, and potatoes as opposed to processed foods loaded with calories and sugar at every meal. 

“Snacks should always be a carbohydrate combined with a fat or protein—for example, carrots and hummus, an apple with nut butter or a whole grain rice cake with avocado,” Feit says. “At meals, try to fill your plate with 1/4 protein, 1/4 fiber-filled carbohydrate, 1/2 veggies and 1-2 servings of healthy fat.”  Eating this way will ensure consumption of all the vitamins and minerals needed to support the thyroid. Choosing healthy carbohydrates can help you feel fuller and avoid weight gain after thyroid issues are treated.

Other ways to heal the thyroid

In addition to dietary changes, the following strategies can help improve symptoms for people with hyperthyroid.

Lifestyle changes

People with hyperthyroidism have a “revved” up sympathetic nervous system (the flight-or-fight part of the immune system), and this can result in difficulty sleeping, increased heart rate and anxiety, Minisha Sood, MD, a board-certified endocrinologist at Lenox Hill Hospital in New York City. So, it’s important to embrace calming lifestyle changes. “Get plenty of rest, engage in gentle, restorative exercises and try to reduce your stress levels with relaxation techniques as much as possible,” says Dr. Sood. When it comes to exercise, Dr. Goddard says she sometimes recommends that a patient avoid exercise until symptoms of hyperthyroidism are addressed.

Supplements

Supplements including fat soluble vitamins, like omega-3 fatty acids, and B vitamins are recommended for people with hyperthyroidism and Graves’ disease, according to Mount Sinai.

Selenium (200 mcg daily) is also sometimes added to a person’s treatment regimen. There is some evidence that it can improve thyroid function. Though adequate data is lacking regarding this mineral, says Dr. Sood.

Medications

Graves’ disease is treated with  two types of medications.  “We often prescribe beta blockers to manage high heart rate, tremors and insomnia,” says Dr. Goddard. While these medications help manage symptoms, they do not treat hyperthyroidism. Beta blockers protect the heart from excessive amounts of thyroid, which can result in heart arrhythmias. 

“We also use antithyroid medications called methimazole and propylthiouracil (PTU) to block the release of thyroid hormone from the thyroid. The goal of these medications is to bring thyroid hormone levels down to a normal level,” Dr. Goddard says. Medication is the fastest way to allow the thyroid to recover because it normalizes thyroid hormone levels. “About 40% of patients may see a remission of their Graves’ disease within 18-24 months of treatment with antithyroid medications,” she says.

It’s important to note that when taking either of these medications, regular blood test monitoring to measure TSH, free T4, and total T3 levels along with liver function and complete blood cell count is imperative, says Dr. Sood. “Obtaining serial thyroid blood tests is important while on thyroid medication to 1. adjust the level of medication and 2. to measure the medication’s effectiveness as well as potential side effects,” says Dr. Sood. 

Other treatments

Hyperthyroidism can be controlled and in many cases may even go into remission, says Dr. Sood. “Radioactive iodine is a treatment which can permanently normalize thyroid function or possibly even induce the opposite of hyperthyroidism (which is hypothyroidism),” he says.

Thyroidectomy, a thyroid surgery to partially or completely remove the thyroid, is another treatment for hyperthyroidism and Graves’ disease, though it is less common than medication or radioactive iodine treatment.

According to Dr. Sood, the best way to heal the thyroid is to get medical attention early, reduce your stress and inflammation with healthy lifestyle changes, and partner with a specialist in endocrinology who can guide you through your treatment options and monitor your progress. 

When to see a doctor

If you’re experiencing confusion, muscle spasms, drastic weight loss, very rapid and/or irregular heartbeat (i.e. over 150 beats per minute), you should seek medical attention immediately, says Dr. Sood. 

If a patient is taking antithyroid medications, a fever and sore throat are cause for concern, and should be brought to the physician’s attention immediately, says Dr. Goddard. If you’re having symptoms of hyperthyroid, it’s always a good idea to visit your healthcare provider for thyroid testing and diagnosis. The thyroid condition is treatable with lifestyle changes and medication.