Hashimoto’s Diet: What Actually Matters (Especially With Celiac)

If you have celiac disease, you’re already on a strict gluten-free diet — and that’s non-negotiable. You need to maintain that no matter what. But if Hashimoto’s has entered the picture, it’s natural to wonder if there is a Hashimoto's diet you should be following.

The short answer is no—but there are a few important facts to understand, and a few persistent myths to clear up.

If you’re curious how I got here — and why I started asking these questions in the first place — I share that story in Celiac Disease and Thyroid Disease: Connect the Dots to Feeling Better.

When we think about diet and thyroid health, it helps to break it down into three questions:

• Are there foods that negatively affect my thyroid — is there anything I should avoid?
• Are there foods that support thyroid health — is there anything I should add?
• Are there foods that interfere with thyroid medication — and how should I manage that?

Let’s take these one at a time.

Are There Foods to Avoid With Hypothyroidism?

Cruciferous Vegetables

You may have seen warnings online about cruciferous vegetables. These include: broccoli, kale, cauliflower and brussels sprouts. The concern is that these foods may interfere with how your thyroid processes iodine. This concern is often overstated and mainly relates to very large amounts eaten raw.

For most people, normal servings — especially cooked — are a healthy part of a balanced diet.¹

Cassava and Tapioca

Cassava is sometimes mentioned in thyroid discussions. If you are on a gluten-free diet you may be concerned because gluten-free products often contain cassava flour or tapioca starch. Tapioca is made from cassava.

Some studies have shown that improperly processed cassava can interfere with iodine uptake. This concern comes mainly from regions where cassava is eaten as a staple and iodine deficiency is common.

If you are eating commercially prepared cassava, or tapioca products as part of a gluten-free diet, and you have adequate iodine intake, there’s no strong evidence that you need to be concerned²

Thyroid and Gluten

You may also see recommendations for people with Hashimoto’s to avoid gluten even if they don’t have celiac disease or gluten sensitivity.

The evidence does not support this. If, like me, you have celiac disease, you must remain 100% gluten-free. If you don’t, there’s no strong evidence that avoiding gluten improves Hashimoto’s.

My doctor did say, however, that he always tests his thyroid patients for celiac disease because they are often seen together. If you find you feel better without gluten, consider that you might have celiac disease or NCGS (non-celiac gluten sensitivity), and speak with your doctor about appropriate testing.³

Foods to Eat with Hypothyroidism

Food won't cure your thyroid, but there are a few nutrients that really matter and some helpful dietary patterns. Let's look at what we actually know from the research.

Iodine

Iodine is essential for thyroid hormone production — which is why it’s added to table salt. But this is a classic case where more isn’t better. While iodine deficiency can cause thyroid problems, too much may worsen autoimmune thyroid disease. Most people get enough iodine from food, so it’s best to talk with your doctor before supplementing.

Foods that contain iodine are: seaweed, seafood, dairy, eggs, iodized table salt.

I try to eat eggs and fish a couple of times per week. Because I often use kosher salt or sea salt in cooking, I use iodized table salt with my meals.¹

Selenium

Selenium is another nutrient that comes up often in Hashimoto’s discussions. It’s found in foods like Brazil nuts, seafood, lean meats, and some grains like rice and oatmeal.

Selenium plays an important role in thyroid hormone metabolism and also supports immune, heart, and brain health. It’s one of the few nutrients that’s been studied specifically in Hashimoto’s — but again, more is not better. Excess selenium can be harmful and may disrupt thyroid function, so don't supplement without talking to your doctor.

For me, I try to include gluten-free grains along with meat and fish into my weekly diet. I also keep a container of Brazil nuts in the pantry to nibble on if I think I'm not getting enough selenium from other sources.⁴

Other Diets that May Help Your Thyroid

There’s also interest in anti-inflammatory, and whole-food diets (like the Mediterranean Diet) with adequate selenium and vitamin D. Some studies suggest modest reduction in thyroid antibodies or improved quality of life. But the evidence isn’t strong or consistent enough to recommend a specific “Hashimoto’s diet.”⁵

Are there foods or supplements that interfere with thyroid medication?

Yes — and this is one area where the guidance is clear.

My doctor recommended taking levothyroxine on an empty stomach, about 30–60 minutes before breakfast, because food can interfere with absorption. This is standard protocol

Additionally, certain foods and supplements should be taken at least four hours away from thyroid medication. These include:

• Calcium (dairy products, calcium supplements, antacids like Tums, certain fortified cereals)
• Soy products.
• Fiber supplements such as psyllium (for example, Metamucil)

Other medications and supplements — including iron — can also interfere with absorption, so it’s important to review everything you take with your doctor or pharmacist.⁶

The Surprise Link Between Hashimoto's and Food Intolerances

I’ve long known that people with celiac disease may have other food intolerances. The link to lactose intolerance is clear and well understood. The link to other food intolerances is less clear.

According to renowned celiac expert Dr. Stefano Guandalini, food intolerance in celiac patients is usually related to gut permeability (leaky gut). Once the gut heals on a gluten-free diet, these food intolerances should improve.⁷

Mine didn’t.

My Personal Experience with Food Intolerance

Dairy became an issue during my second pregnancy, decades before my celiac diagnosis. I knew it wasn’t lactose, because I still reacted to lactose-free milk products. Later I learned about casein and realized that I have a casein intolerance.

A few years after the celiac diagnosis, eggs started to cause nausea and diarrhea. As fun and challenging as it’s been to learn gluten-free and egg-free baking, I missed eggs.

Then by sheer chance I read a comment in a celiac forum. The commenter mentioned that her casein and egg intolerances were likely linked to her Hashimoto’s.

What!?!

I had just been diagnosed with Hashimoto’s. I had casein and egg intolerances. Could it be that my thyroid was causing this all along? 

My mind was blown!

A few quick google searches uncovered links between Hashimoto’s and specific food intolerances — eggs and milk are among the most common.⁸

Can Treating the Thyroid Cure the Food Intolerance?

After about six months on levothyroxine, I noticed my digestion was calmer. The constant bloating was better. The post-meal diarrhea was gone. 

So I tried an egg. 

And waited. 

Nothing happened. 

No bloating, no mad dash to the bathroom. Nothing. 

I’ve cautiously added butter back into my diet with no issues. Then small amounts of cheese and yogurt. Still no reaction.

Nothing in my research suggests that normalizing thyroid function cures food intolerance. This is my personal experience. However, research does describe a “gut-thyroid axis.” So, it seems plausible that treating the hypothyroidism could calm the immune system and in turn, the gut.

For more about food intolerances and how they relate to celiac disease, see my updated page on celiac and food intolerances.

My Bottom Line on Diet and Hashimoto’s

If you read my work, you know that I'm all about natural healing. Food is medicine, and if there is a way to solve a problem with diet, I'm there. Although eating well may help you feel better, Hashimoto's is not a condition that can be cured with diet. Here are the main points to remember:

• You cannot treat Hashimoto's on your own. Work with your doctor and take your medication as prescribed.
• There’s no single “Hashimoto’s diet,” though some people feel better eating a less inflammatory, whole-food diet.
• If you have celiac disease, staying strictly gluten-free is essential.
• Most people get enough iodine and selenium from food — supplement only with medical advice.
• Take levothyroxine on an empty stomach: about an hour before food and four hours away from calcium, soy, iron, and fiber supplements.
• Always check other medications and supplements for possible interactions.

For me, focusing on consistency, taking my medication as prescribed and eating a well-balanced, gluten-free diet (for my celiac) has been the key to feeling better.

And remember, I'm sharing my personal experience, advice from my doctor, and guidance from trusted sources. But each of us is unique. Your physician and a certified nutritionist can help you create your personal plan.

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