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Nutrition for Hashimoto’s Disease: Things You Need to Know

Paleo Food

Hashimoto’s disease or Hashimoto’s thyroiditis is a thyroid condition that affects a lot of people.

There are a lot of aspects of how nutrition can play a role in the management of it, so this post will cover a lot of key points that are worth being aware of.

What is Hashimoto’s?

Hashimotos Thyroid

Hypothyroidism is a condition where not enough thyroid hormone is being produced. This can happen for a variety of reasons, but Hashimoto’s disease is one of the most common ones.

With Hashimoto’s, the body’s own cells attack and damage the thyroid gland.

Basically, the immune system mistakenly views normal thyroid cells as foreign tissue and produces antibodies to destroy them. This is what leads to the reduced production of thyroid hormones.

Common symptoms of hypothyroidism are:

  • Weight gain
  • Dry skin
  • Poor memory
  • Fatigue
  • Feeling cold
  • Sore muscles and joints
  • Constipation
  • Poor memory
  • Joint and muscle pain
  • Depression
  • Reduced libido

Thyroid hormones normally play a role in regulating these functions in some way, which is why these symptoms can occur when hypothyroidism is involved.

Left untreated, other complications can also occur. One of the many examples of this is the development of a goitre due to the enlargement of the thyroid in some cases.

Goitre

How Is It Diagnosed?

Put simply, the best thing to do is see a GP and start the process of getting a formal diagnosis.

They will likely:

  • Test for anti-thyroid antibodies: The presence of these is an indicator of Hashimoto’s. That said, they are not necessarily present in all cases.

  • Test Thyroid Stimulating Hormone (TSH) levels: Thyroid stimulating hormone is exactly what it sounds like. It stimulates the thyroid to produce thyroid hormones (T3 and T4).

    If the thyroid is not able to produce enough of these hormones, TSH can be produced in larger amounts from the pituitary gland in a bid to increase the production. So elevated TSH levels can be one of the best indicators of hypothyroidism.

  • Test Thyroxine (T4) levels in the blood: By measuring free T4 levels, you can directly find out if you have a low level of thyroid hormones. However, it is still possible to have levels within the normal range and have issues, since an abnormally high level of TSH can keep it in this range.
Hashimotos Disease Summary

It’s also worth mentioning that Hashimoto’s does not always cause hypothyroidism. You can have the thyroid peroxidase (TPO) antibodies while also having normal TSH and free T4 levels. Your thyroid could be functioning normally while having the antibodies indicating Hashimoto’s.

Medical Options

While I want to get into the nutritional aspects, since that is where I can really provide value, it is worth taking a second to discuss medical options.

The reason I say this is because Hashimoto’s is complex.

Some people need medication. Others do not. Some people get more symptoms, some people get fewer symptoms.

Sometimes people have glaring gaps in their nutrition relevant to hypothyroidism which could be easy fixes that make a world of difference.

At the other end of the spectrum, I have seen some people obsessing about trying to solve it through nutrition for multiple years while struggling with symptoms that could have been addressed with medication.

Taking a black and white approach where you only look at one avenue as the only solution could make things far more difficult than they need to be.

If the body is not producing enough thyroid hormone, thyroid replacement medication is typically what is used to correct this deficiency.

The most common approach to treat hypothyroidism is to take a medication called levothyroxine. Levothyroxine is converted to active thyroid hormone (T4) in the body.

Levothyroxine Medication Tablets

When dosed correctly, it generally helps address the symptoms associated with hypothyroidism. It is basically replacing what is lacking.

The dosing often needs to be adjusted over time though. Too little and symptoms of hypothyroidism are more likely to remain. Too much leads to hyperthyroidism which causes other issues.

From a dietary perspective, it is best to take levothyroxine separately from food. At least 30-60 minutes away from food is a good strategy. Or even just having the medication on an empty stomach in the morning at least 30-60 minutes before breakfast.

This is because there are a lot of foods and things other like coffee, calcium and iron supplements that can potentially affect the absorption of the medication.

Most people respond well to levothyroxine when dosed well. But it is worth speaking about other options with your doctor when necessary.

General Nutrition Thoughts

Healthy Food

Nutrition can help in a lot of ways, so the below options are focused on that. But please do not try to view nutrition as the sole “cure” of Hashimoto’s. It is more effective in some cases, but in a lot of cases, it is just one piece of the puzzle that can help.

Some aspects of nutrition come down to general healthy eating principles, which are typically going to be beneficial regardless.

Other aspects are more specific, for example, if somebody has a clear deficiency in something that is important for thyroid health.

And other options are what I would classify as either of interest or potentially relevant. They typically are things that have some positive research, mixed research, or anecdotal support. I want to cover most of these topics.

Iodine

Iodised Salt

The thyroid gland requires iodine to make thyroid hormones. Therefore, this can be a situation where is somebody has a clearly inadequate intake of iodine contributing to their hypothyroidism, iodine can be the solution.

Iodine deficiency is relatively rare in developed countries though.

Naturally, iodine is found in the dirt that plants are grown in. Therefore, it is naturally part of the food supply. Particularly for people who eat foods coming from a variety of sources.

An issue can arise in areas where the land is low in iodine.

A solution for this is iodine fortification of products. In Australia, salt is typically iodised. This addresses this problem unless somebody completely avoids salt AND is consuming naturally iodine poor foods.

While iodine is important, it is not something that I would recommend supplementing without guidance. And I would not supplement it unless it is clear iodine intake has been insufficient. Consuming too much iodine can worsen the condition.

Goitrogens

Cruciferous Vegetables

Another common recommendation is to avoid goitrogens. These are substances that reduce the uptake of iodine into the thyroid gland.

Based on this mechanism, goitrogens are mainly relevant if low iodine is a contributing factor, which it is not overly common these days. And as mentioned in the previous section, excess iodine can be a contributor to hypothyroidism too.

But goitrogens can potentially also play a role in enzymes that form the basis of thyroid hormones. They can also potentially interact with TSH levels as well. So, there are some theoretical reasons for concern.

Foods that are high in goitrogens include broccoli, cauliflower, cabbage and bok choy. It is a relatively long list, but at minimum, most dark leafy greens are goitrogens.

The research is not super clear on goitrogens. The consensus is that moderate amounts are okay. But excessively large amounts likely should be avoided just to be cautious.

Completely avoiding them can unnecessarily reduce vegetable and micronutrient intake.

Vegetables are typically beneficial, so we do not want to needlessly reduce them. But it also makes sense to avoid having massive amounts of these specific vegetables consistently.

And if it were playing a role, but you were consistent with your intake and were on medication, your medication could be adjusted to account for it.

Soy

Soy Containing Foods

Soy is technically a goitrogen too, so fits into the discussion above as well.

Beyond that though, a lot of people recommend cutting out soy.

But there actually is a fair bit of research on this topic. So, we can make some interpretations based on that.

A review of 14 studies on people with hypothyroidism found little effect of soy on markers of thyroid function.

These studies were done on people who had appropriately dosed medication though. They had their thyroid levels within the targetted range already. Basically, it showed minimal effect on the effectiveness of the medication, or the dosage required.

That is not to say it is not a concern at all. There are still some theoretical reasons that soy could affect hypothyroidism.

My interpretation would be to avoid an exceptionally high soy intake. But I would not actively try to avoid soy, particularly if it was not something you were going to consume in large amounts anyway.

The reason why this is worth sharing is that people often give blanket statements like “avoid soy.” This could needlessly be adding restriction and frustration to somebody who only has soy in small/moderate amounts anyway. 

Gluten

Coeliac disease gluten free

A gluten-free diet is one of the most strongly promoted changes recommended by people. Often it is supported by anecdotal evidence. Data in the more formal research is not as strongly in support.

In the case of coeliac disease, it is a no-brainer to cut out gluten completely.

There are also often thyroid antibodies present in coeliac disease too, which contributes to this. And those with Hashimoto’s have a higher prevalence of coeliac disease.

So obviously it makes sense to test for coeliac disease. But without it, is it worthwhile considering going gluten free?

Some research indicates that it might reduce thyroid antibodies.

But the overall body of research is still mixed. And there also is surprisingly little research on the topic in general.

My interpretation of the research is that it is not overly likely to make much difference, assuming all other factors are equal. But there is still potential.

The combination of anecdotal support and the fact that you can still put together a great diet with or without gluten means that it is an option worth thinking about.

If you have an interest in going gluten-free, it could be worth exploring. If you personally have found benefits from being gluten-free, it probably makes sense to continue doing that.

Dairy

Dairy foods

Dairy is a bit of a similar case to gluten. There is far more anecdotal support than research-based claims.

While there are blanket statements such as “avoid dairy” there is a more nuanced look I would take at it first.

Part of that nuanced approach would be to consider lactose intolerance first. The prevalence of lactose intolerance in those with Hashimoto’s is insanely high. In a study of 83 people, 75.9% of them had lactose intolerance.

That is huge.

Based on that study, limiting lactose intake also played a role in improving thyroid function too which is interesting.

The reason why I would explore that first is that the management of lactose intolerance is far easier than avoiding dairy.

Lactose-free milk is an option. Lactase tablets exist. Hard cheese like cheddar is typically low in lactose. It also means you can likely have small amounts of lactose without symptoms.

Lactose Contents of Foods

I would explore that option first. I would not completely rule out dairy as being a factor though.

Similarly, to gluten, you can have a great diet without dairy if it is structured well. If you personally have an interest or have found benefits from eliminating dairy, it is an option worth exploring.

Selenium

Selenium Rich Foods

Selenium is found in large quantities within the thyroid gland. It is involved in the process of producing enzymes that play a role in thyroid hormone metabolism.

If somebody has a sub-optimal amount of selenium, it could be a contributing factor in the condition.

A review of the research on the topic highlighted that selenium supplementation can decrease thyroid antibodies and improve general wellbeing.

Good news all around. This is a part of why people dismissing dietary factors is silly. It obviously plays a role.

Once again, it is nuanced though. The effect was more pronounced in those who had a selenium deficiency at the start of the trials. This lines up with the logic perfectly though.

It is an area where more research is needed though. Another review on the topic highlighted that selenium supplementation can be promising, but in practice is not always that consistently helpful. It is also worth being aware that there are a lot of downsides to over supplementing selenium. It can even be dangerous in large amounts.

Consuming 100-200ug per day of selenium is typically a good approach. Ideally having it mostly come from food is a safe bet too.

My personal approach would be to regularly consume some form of selenium-rich food. But I also would be cautious of large amounts of it through food or supplements, due to the downsides of having too much.

Zinc

Zinc-Rich Foods
Foods Highest in Zinc. Healthy eating. Flat lay

Zinc is required for the production of T3, T4 and TSH. Therefore, at minimum, a deficiency needs to be avoided.

Beyond that, a study has indicated that taking 30mg of zinc-gluconate helped improve thyroid function in hypothyroid subjects.

Thyroid hormones are also required for the absorption of zinc, which should be factored in.

While the research that has been done so far has been promising, it is still early. There is still not a lot of research on this topic.

Vitamin D

Vitamin D3

Vitamin D plays a role in so many aspects of how our body functions. It is not overly surprising that vitamin D can play a role in Hashimoto’s as well.

It is relatively common for people to have a vitamin D deficiency in general.

Being at the bottom end of what is commonly accepted to be the healthy range is still likely sub-optimal. This means that a large percentage of the population has a sub-optimal amount of vitamin D.

People with Hashimoto’s are even MORE likely to have a sub-optimal amount of vitamin D. This is just the first hint that this link matters.

Research on the topic has indicated that vitamin D supplementation can help reduce TPO and thyroglobulin antibodies. TSH levels have also reduced, which is another way in which it can be beneficial.

It is early in the research though, so it is not a strong link. But if it is relevant, it is likely that the benefit seen will be mostly beneficial to those who have low levels of vitamin D to start off with.

Supplementing with vitamin D is cheap and safe (if not done excessively), so it is one of the first things I would look at as a potential easy win.

B12

Sources of B12

Vitamin B12 deficiency is more prevalent in Hashimoto’s than in the general population. It is also linked with adverse outcomes.

Based on the research, lower B12 levels is linked with higher anti-TPO antibodies.

It makes a lot of sense to check B12 levels regularly via a blood test if you have Hashimoto’s. If it is at a sub-optimal level, it would be beneficial to supplement or eat more B12 rich foods.

If you were to take a supplement that also contained biotin (which is not uncommon in a B-complex or multivitamin), it is encouraged to discontinue it for 3 days prior to thyroid blood tests. This is because biotin can lead to misleading results on the thyroid assay.

Magnesium

Magnesium

At a minimum, severely low blood levels of magnesium are strongly associated with Hashimoto’s and the symptoms associated with that.

Utilising a blood test to check for this is the first step.

Then addressing it either through diet or supplementation would be the next step.

There could also be benefits still even if you do not have severely low levels. Research on the topic is limited though.

It is not uncommon for people to have sub-optimal intakes of magnesium in comparison to the recommended daily intake. Even if the levels in the blood are adequate, it does not necessarily mean intake has been optimised.

If you have a great diet, it is likely you consume sufficient magnesium. But if you fall into the large percentage of people who do not consume enough, either addressing this through food or supplementation could be beneficial.

Iron

Sources of iron

Iron deficiency is more common in Hashimoto’s than in the general population. Part of this though is because coeliac disease is also more prevalent. Coeliac disease reduces iron absorption, which is one reason for this link.

Iron is required to produce thyroid hormones. Obviously, because of this Iron deficiency reduces the production of thyroid hormones. TSH and the size of the thyroid gland also increase under these circumstances.

This is another explanation as to why iron deficiency is more prevalent for those with Hashimoto’s. Iron deficiency itself might contribute to Hashimoto’s development. And it is another reason why it is worth testing your iron levels.

Anaemia is a common outcome of low iron. Iron deficiency anaemia leads to fatigue. And fatigue is already a common symptom of Hashimoto’s too.

As you can imagine, addressing an iron deficiency if it is present can help improve the outcomes relevant for Hashimoto’s.

If taking iron supplements, it is encouraged to keep them multiple hours separate from your thyroid medication to avoid any interactions.

Fish Oil

Fish oil capsules

It is currently recommended that those with Hashimoto’s should aim for 1-2g of fish oil per day on average. This could come through either food or supplements.

Even if following a plant-based diet, there are still options to achieve this.

A lot of the proposed benefits related to this come from an inflammatory standpoint, which will be discussed in the next section.

From a research perspective, while there is some rodent research showing promise, there is not much human research on this topic.

Anti-Inflammatory Style Diet

Anti-inflammatory foods

Hashimoto’s Thyroiditis literally has “itis” in the name. This is referring to inflammation.

It is logical to then jump to the conclusion that perhaps an anti-inflammatory style diet could help.

Obviously, it is way more complex than something that simple. But the idea is worth exploring.

Anti-inflammatory diets have a lot of different variations. Common themes often include lots of fruits, vegetables, nuts, seeds, wholegrains, and healthy fats. But even a lot of those aspects are debated.

Oxidative stress is higher in those with Hashimoto’s on average. And consuming more fruits, vegetables and having a lower amount of body fat have all been associated with reduced oxidative stress and inflammation in those with Hashimoto’s.

Whether or not an anti-inflammatory diet matters, typically the foods in this style of diet are particularly rich in micronutrients.

As highlighted in previous sections, micronutrient deficiencies are quite common in people with Hashimoto’s. This style of diet could indirectly address that aspect of management.

Constipation Management

Kiwi Fruit, Linseed, yoghurt and banana

Thyroid hormones are involved in a lot of the functions of the body, including digestion.

Hashimoto’s can lead to bowels slowing down.

Managing Hashimoto’s overall could indirectly help with this. But there are also specific constipation things you can focus on.

My first recommendation would be to read this article on constipation nutrition tips.

That will thoroughly cover a few key things which will make a big difference.

The short version is that it is worth looking at:

  1. 5-10g of psyllium husk or Metamucil per day
  2. 1-2x serves of kiwi fruit per day
  3. 5-20g of linseed/flaxseed per day

Ideally, you add those things in without dramatically increasing your overall fibre intake too quickly. You might even need to reduce your fibre intake elsewhere to allow for them.

All these things have been shown to improve symptoms of constipation by >30% on average.

Another trick some people utilise is magnesium citrate supplementation for constipation. If used in high dosages, it can have a laxative effect. Typically, 300mg is a normal dosage, but some people encourage higher.

Magnesium Citrate

This could be even more impactful if you have Hashimoto’s and are potentially more likely to benefit from magnesium supplementation than the average person.

Weight Management

Components of Energy Expenditure

Since thyroid hormones regulate our metabolism, it is not uncommon for weight loss to be harder if thyroid hormones are lower. If hypothyroidism is not addressed, energy expenditure can be lower.

This is part of why people often gain weight with hypothyroidism.

I have a huge amount of empathy for this situation.

Hypothyroidism does not change the rules for weight loss. A calorie deficit is still required.

But can be more difficult to create one though. Both due to the energy expenditure aspect and the other symptoms of Hashimoto’s.

This is assuming that T3 and T4 are reduced though.

If thyroid levels are within the healthy range either with or without medication, theoretically this difference should no longer exist.

A study exploring this phenomenon identified a 4% difference between the resting expenditure when variables such as lean mass were equated for those who were treated with thyroid medication versus those who naturally had no thyroid concerns. This is very close, and the difference could be explained by other variables such as insulin resistance.

As mentioned previously though, the ideal medication dosage can be a moving target. While there is theoretically minimal difference once medicated, in practice it can be a bit more complex.

If T3 and T4 are lower than ideal and this is not addressed though, energy expenditure will be reduced.

It is hard to find numbers quantifying the average reduction in energy expenditure since cases are so individual. Based on the research, I would estimate that a maximum reduction of ~25% in resting energy expenditure would be at the more extreme end of the spectrum.

If 25% was the maximum, most cases would have to be lower. A reduction of ~15% seems more common.

This makes it harder to lose weight than you would expect. You can theoretically overcome this by eating less calories to make up the difference.

That is easier said than done in a lot of cases though. It makes sense why a lot of people with Hashimoto’s struggle with their weight.

One of the reasons why I think quantifying it is important is because it allows us to know (or estimate) the size of the barrier to overcome.  

Personally, I find “roughly a 15% reduction in resting energy expenditure” more helpful than “it is harder to lose weight.” It sets a target that is possible to understand and achieve.

Conclusion

Hashimoto’s is a complex condition. If you spend a lot of time reading about it, you will find extremes at both ends of the spectrum. Some people act as if there is not much you can do from a nutrition perspective that can help. Others act as if a few changes will completely solve the condition for everybody.

The answer is somewhere in the middle for most people.

There are plenty of things you can do that are likely to help improve the management of the condition. But it is a complex condition and diet alone is typically not a cure. Other aspects of management outside of nutrition need to be taken into consideration.

By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been fascinated by all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.