How milk causes inflammation and worsens Hashimoto’s

Photo: Noemí Jiménez/Unsplash. Design: BOOST Thyroid.

Photo: Noemí Jiménez/Unsplash. Design: BOOST Thyroid.

What you should know about the impact of dairy on thyroid health

Consuming animal milk products can impact your health in many ways. While animal milk provides clear benefits, it also causes a lot of problems—especially for people with autoimmune conditions.

A BOOST Thyroid survey has shown that 3 in 10 people experience problems after consuming cow milk products, 1 in 10 people have issues with milk from any animal source, while 2 in 10 people are not sure which type of milk may be the cause of their problems.

You can still take part in our survey here. We will update the results in a few months.

Food and inflammation

Inflammation is one of many biological processes that helps humans survive and fend off bacteria and viruses. In order for people to survive— and be able to eat food—the immune system has learned how to tolerate certain elements from the environment through a mechanism called oral tolerance.

If inflammation is chronic or long lasting, there is a risk the immune system won’t tolerate certain things and will begin acting against the body (1). Even if inflammation is subtle, it can worsen health and cause premature aging (2).

Common signs of inflammation in the gut:

  • Chronic diarrhea

  • Bloating and gassiness

  • Feeling tired

  • Pain while digesting foods

  • Poor sleep

Autoimmune chronic conditions can be triggered by food choices. Every time a person eats, there is short-lasting inflammation as the food passes through the intestines—this significantly worsens when a person has an autoimmune condition or a leaky gut (3-5).

Animal milk is a common nutrient, making up 14% of total food intake in western countries. In certain cases milk can prevent inflammation, while in others it intensifies it (6-8).

How animal milk causes inflammation and Hashimoto’s flare-ups

Animal milk contains a very high concentration of two inflammation promoting substances: antigens (substances that trigger inflammation) and saturated fats (9).

Research has shown that different types of milk products can affect gut health in various ways:

  • Milk products with high fat content will cause more inflammation (10).

  • Fermented milk products protect against inflammation, most likely because they contain a lot of beneficial probiotics (11,12).

Genes and bacteria

Certain gene mutations can predispose people to digestive issues .Mutations in even just one of more than 200 different genes can increase the risk of digestive issues (13, 14).

Bacteria also plays a role.  The bacterial composition of the gut (aka the microbiome) is very important in determining the risk of  developing an autoimmune condition (15).

Most immune cells are located in the gut, as well as bacteria. There is 10x more bacteria located in the gut than there are cells in the entire body (16). If the gut would be laid out flat, it would have a surface of approximately 200 square meters (or 2,153 square feet). The large surface area of the gut makes it easier for the many interactions to take place between the immune cells, bacteria, and the food we eat (17).

Similarities between milk and human protein

Animal milk proteins share a lot of similarities with human proteins because of their compositions—this might be the cause of milk-triggered inflammation.

Milk contains more than 400 different proteins, including albumin (aka whey) which causes the majority of digestive problems.  (18-20).

If an intolerance develops when consuming milk products, the immune system will start reacting against milk proteins and will  begin to memorize how milk protein looks. Sometimes immune cells will then look for similar proteins, even when there is no animal milk being digested. In certain cases, similar proteins can be found in thyroid cells, causing an autoimmune reaction (21).

Although lactose (a milk sugar) may not be directly connected to autoimmune thyroid problems, it may cause issues for people with lactose intolerance. If the intolerance is severe, T4 medications (which contain small amounts of lactose) may cause problems.

Alternative milk

If you’re avoiding cow’s milk, there are many varieties of plant milks—or other animals’ milk— that your immune system might  tolerate. Animal milk is full of proteins—if you’re used to a diet high in milk and plan to use an alternative milk ,use, make sure you’re substituting the proteins found in animal milk as plant milks have different proteins. A drop in protein intake can lead to a drop in fT3 levels (22, 23).

Make sure you are taking in all essential amino acids (the building blocks of proteins), which alternatives to milk may help with. You should talk to your healthcare provider about which types of proteins you should require.

If you suspect dairy is causing your Hashimoto’s flare-ups, try a week or two without animal milk or milk products.

Track your diet in BOOST Thyroid and observe if your digestion, energy, and sleep improves.


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  2. Candore G, et al. Low grade inflammation as a common pathogenetic denominator in age-related diseases: novel drug targets for anti-ageing strategies and successful ageing achievement, 2010

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  7. Panagiotakos DB, et al. Dairy products consumption is associated with decreased levels of inflammatory markers related to cardiovascular disease in apparently healthy adults: the ATTICA study, 2010

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  19. Wasmuth HE, et al. Cow's milk and immune-mediated diabetes., 2000

  20. Bohl M, et al. Whey and Casein Proteins and Medium-Chain Saturated Fatty Acids from Milk Do Not Increase Low-Grade Inflammation in Abdominally Obese Adults, 2016

  21. Vojdani A. Molecular mimicry as a mechanism for food immune reactivities and autoimmunity, 2015

  22. Shi ZX, et al. The effect of dietary protein on thyrotropin-releasing hormone and thyrotropin gene expression, 1993

  23. Barrows K, et al. Effect of a high-protein, very-low-calorie diet on resting metabolism, thyroid hormones, and energy expenditure of obese middle-aged women, 1987