Do Certain Foods Affect Your Thyroid?

  • Medical Reviewer: Mahammad Juber S, MD
Medically Reviewed on 6/24/2022

What are hypothyroidism and hyperthyroidism?

The thyroid is one of the human body's major glands in the endocrine system that produces and regulates hormones. Foods that affect the thyroid include soy products and gluten.
The thyroid is one of the human body's major glands in the endocrine system that produces and regulates hormones. Foods that affect the thyroid include soy products and gluten.

Have you ever wondered what foods are bad for your thyroid? If you’re one of the 20 million Americans who have been diagnosed as having a thyroid condition, you might be concerned about how your diet affects your thyroid health. 

Most doctors and researchers would tell you that there's no cure for thyroid disease or a “thyroid diet,” regardless of the numerous books written on the subject. But, it has been proven that certain foods and supplements do affect thyroid function.

Eating too much of some of these things may increase your thyroid health, while others interfere with how well your body absorbs your thyroid medication. This guide will help you learn more about thyroid conditions to gain a better understanding of how careful you should be with your diet.

The thyroid is one of the human body’s major glands in the endocrine system that produces and regulates hormones. There are two main kinds of thyroid disease:

Both of them can cause mild to severe symptoms.

What are the main symptoms of thyroid disease?

Hypothyroidism and hyperthyroidism symptoms vary from person to person, but only a few tend to affect everybody with this disease. You may show one or more of these symptoms if you have thyroid disease:

Initially, these symptoms may be so mild that you may overlook them or find another explanation for them, like stress, poor diet, or lack of good sleep — and rightly so because these symptoms are so general that they could be the result of many diseases.

This is why if you think you have thyroid, it’s very important to talk to a doctor who's knowledgeable about thyroid conditions. 

What are the causes of thyroid disease?

Hypothyroidism is usually caused by Hashimoto’s disease — an autoimmune condition — your body’s own immune system mistakenly attacks the thyroid as if it were a virus or bacteria. Over time, the thyroid can't produce as much thyroid hormone as it once did.

Other reasons for hypothyroidism include consuming too little iodine — which is necessary to make thyroid hormones — or removal of the thyroid removed to treat thyroid cancer

Hyperthyroidism may be also caused by an autoimmune disease called Graves' disease or by other conditions like thyroiditis, which may affect you after you give birth to a baby.

If you have Hashimoto’s or low thyroid function caused by other factors, your doctor may prescribe synthetic thyroid hormone medication. People who have hyperthyroidism need to take anti-thyroid medication, which lowers their thyroid's ability to produce the extra hormones that make them sick.

To feel your best, it's important to note which foods may interfere with this medication or your thyroid health in general.

Who does thyroid disease affect?

Overall, thyroid disease affects women more often than men, and it affects older people more than it does younger people. This does not mean that you cannot have thyroid trouble when you are young. People who have additional autoimmune diseases such as Type 1 diabetes are at higher risk for developing thyroid problems. 

What foods affect the thyroid?

If you have a diagnosed thyroid condition, you may want to speak to your doctor about whether you need to change your diet. The following foods can have an effect on thyroid health in general or they may interfere with your medication.

Soy products

Soy foods such as edamame, soymilk, and tofu may affect thyroid health. Soy has also been shown to change the way your body absorbs your thyroid medication.

Most people probably don’t eat enough soy to affect their thyroid levels, but if you're considering becoming vegetarian or vegan, it may be a good idea to speak to your doctor about closely monitoring your levels during the transition.


Eating gluten-free isn’t a fad for people who have been diagnosed as having celiac disease — also an autoimmune condition. People with celiac often have thyroid disease too. This can worsen when they eat gluten, which can lead to inflammation in their intestines, affecting how much of the thyroid medication they can absorb. 


Hyperthyroidism: Symptoms, Treatment, Medication See Slideshow

What medications and supplements affect the thyroid?

Though there isn’t a universal diet appropriate for every person with thyroid problems, there are a lot of guidelines surrounding when to take thyroid medication. You should aim to take your medicine as far away from other medications, vitamins, and supplements as possible.


For people with thyroid conditions as well as those who're just trying to keep their thyroid glands healthy, it’s important to pay attention to iodine intake. Too much iodine in your diet can lead to hypothyroidism and it can also contribute to symptoms of hyperthyroidism. Don't take iodine supplements unless your doctor tells you to. If you take a medication with iodine in it, it may put you at higher risk for developing a thyroid condition.

Vitamins and minerals

Both calcium and iron supplements can interfere with the way your body absorbs thyroid medication. Don't stop taking vitamins that you need because you're worried that they will affect your thyroid medication — just take them at least 4 hours before or after your medication.


Certain medications for cholesterol, those that treat ulcers, and antacids like sucralfate can interfere with the absorption of your thyroid medication. They don't affect the thyroid directly, but you should be sure to take them separately from your medication.

Fiber supplements

Fiber supplements are great at keeping you "regular," but they may also be carrying your medication out of your body before it's had the chance to properly absorb it. Don’t take thyroid medication at the same time you take fiber. Eating too much fiber in foods can have the same effect as fiber supplements.

How can I find more information about diet and thyroid health?

Living with a thyroid condition can be confusing as there's so much information aimed at thyroid patients. Do you still have questions about your thyroid condition or wonder what foods are bad for the thyroid? Check with your doctor before adding any new supplements to your routine or making drastic changes to your diet.

Medically Reviewed on 6/24/2022

Cleveland Clinic: "Thyroid Disease."

Clinical Medicine & Research: "Celiac Disease and Autoimmune Thyroid Disease."

Garla, V., Gosi, S. StatPearls. "Subclinical Hypothyroidism," StatPearls Publishing, 2021.

Mayo Clinic: "Soy: Does it worsen hypothyroidism?"

Thyroid: "Excessive Iodine Intake and Subclinical Hypothyroidism in Children and Adolescents Aged 6-19 Years: Results of the Sixth Korean National Health and Nutrition Examination Survey, 2013-2015."

UCLA Health: "How Should I Take Thyroid Hormone (L-thyroxine)?"

Women's Health: "Thyroid Disease."