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Polyautoimmunity, Multiple Autoimmune Syndrome, Hashimoto's

Learn about Hashimoto’s thyroiditis and the risk of polyautoimmunity and Multiple Autoimmune Syndrome (MAS).
Polyautoimmunity, Multiple Autoimmune Syndrome, Hashimoto's
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When you have Hashimoto’s disease, it’s enough to manage this common but sometimes challenging autoimmune condition. But when you have Hashimoto’s, you should also be aware that you face an increased risk of polyautoimmunity, a medical condition where a person has two autoimmune diseases, and Multiple Autoimmune Syndrome (MAS), where three or more autoimmune diseases coexist. In this article, we’ll explore the polyautoimmunity and MAS connection in Hashimoto’s patients, and what you can do to reduce your risks.

Autoimmune disease and Hashimoto’s Thyroiditis

Autoimmune diseases occur when the body’s immune system mistakenly attacks healthy cells, tissues, organs, and glands, perceiving them as “foreign” (like viruses, bacteria, and other pathogens.) The exact cause of autoimmune diseases is unknown, but they are believed to develop as a result of both genetic and environmental factors.

One of the most common autoimmune diseases is Hashimoto’s thyroiditis, also known as Hashimoto’s disease. In Hashimoto’s, the immune system creates antibodies that attack thyroid cells, leading to chronic inflammation of the thyroid gland. Over time, the autoimmune attack can damage the thyroid gland and lead to hypothyroidism, a condition in which the thyroid gland doesn’t produce enough hormones to regulate the body’s metabolic functions. Hashimoto’s thyroiditis is the most common cause of hypothyroidism in the United States.

What is polyautoimmunity?

Polyautoimmunity is a condition where a patient has two autoimmune diseases. In some cases, polyautoimmunity can be latent, meaning that an autoimmune patient with one diagnosed disease also has elevated antibodies and biomarkers of another autoimmune disease that has not fully manifested. In other cases, two distinct autoimmune conditions are diagnosed.

According to research, an estimated 14 to 25% of Hashimoto’s patients have a second autoimmune disease. The most common conditions coexisting with Hashimoto’s include:

  • Alopecia
  • Addison’s disease
  • Rheumatoid arthritis (RA)
  • Chronic autoimmune gastritis
  • Vitiligo
  • Polymyalgia rheumatica
  • Celiac disease
  • Type 1 diabetes
  • Sjogren’s syndrome
  • Multiple sclerosis (MS)
  • Systemic lupus erythematosus (SLE)
  • Sarcoidosis/systemic sclerosis
  • Myasthenia gravis

What is Multiple Autoimmune Syndrome (MAS)?

MAS is a condition in which a minimum of three distinct autoimmune diseases have been diagnosed. It’s sometimes referred to as the “kaleidoscope of autoimmunity.” Experts estimate that about 25% of patients with any one autoimmune disease will develop additional autoimmune diseases.

Three distinct groupings of MAS have been identified, two of which include autoimmune thyroid disease (including Hashimoto’s thyroiditis and Graves’ disease.)

  • Type 1 MAS: includes myasthenia gratis, thymoma, polymyositis, and giant cell myocarditis
  • Type 2 MAS: includes Sjogren’s syndrome, rheumatoid arthritis, scleroderma, and autoimmune thyroid disease
  • Type 3 MAS: includes systemic lupus erythematosus, dermatomyositis, Sjogren syndrome, Addison’s disease, vitiligo, dermatitis herpetiformis, and autoimmune thyroid disease

What are the symptoms of polyautoimmunity and MAS?

The symptoms of polyautoimmunity and MAS vary depending on the specific autoimmune diseases present in a patient. However, several common symptoms tend to be shared by autoimmune disease patients, including signs and symptoms such as:

  • Joint pain
  • Hair loss
  • Fatigue
  • Raynaud’s phenomenon - a condition involving spasms in the blood vessels, usually in the fingers and toes, that limits the blood flow to extremities and makes them feel numb, cold, and painful in response to cold temperatures or stress.

What increases the risk of polyautoimmunity and MAS?

Researchers have found that specific genes – called susceptibility genes – are shared by several autoimmune diseases, indicating that people with these genetic factors are at higher risk of these conditions.

There is also evidence that the risk of polyautoimmunity and MAS is linked to the exposome. The exposome is the measure of all the non-genetic exposures of an individual in a lifetime and how those exposures relate to health. The exposome includes environmental and occupational exposures, diet, and lifestyle. These exposures interact with an individual’s genetics, physiology, and epigenetics -- how behaviors and environment can change how your genes work.

Researchers are increasingly focusing on the role of the gut microbiome as a risk factor for autoimmune disorders. It’s now known that imbalances in the microbiome -- the collection of microorganisms, including bacteria, fungi, viruses, and parasites that live inside and on our bodies – can lead to multiple autoimmune disorders.

At the 2022 annual meeting of the American Thyroid Association, Researchers presented research titled “The “Leaky Gut” in Patients with Hashimoto’s Thyroiditis Associated with Polyautoimmunity.” The study looked at intestinal permeability – known colloquially as “leaky gut” – and the relationship to polyautoimmunity in Hashimoto’s patients.

To conduct the evaluation, researchers measured levels of zonulin, which regulates intestinal integrity, and lipopolysaccharide (LPS), a component of bacterial cell membranes. The researchers found that patients with Hashimoto’s who had polyautoimmunity had significantly higher levels of zonulin and LPS compared to patients who only had Hashimoto’s.

The researchers concluded that a leaky gut and a higher level of inflammation characterize the polyautoimmunity in Hashimoto’s patients – even when the patient has no other gastrointestinal conditions or involvement.

What can you do?

While you can’t change your family history of or genetic risk factors for polyautoimmunity or MAS as a Hashimoto’s patient, there are some things you can do to minimize your risk factors.

Get tested

If you or your doctor suspect you have developed another autoimmune condition apart from Hashimoto’s, your doctor can order antibody and imaging tests to look for any biomarkers and signs specific to another autoimmune disease.

In addition, Hashimoto’s patients may want to consider testing zonulin and LPS levels. A zonulin test – available as a laboratory blood test, stool test, or home bloodspot kit – measures zonulin levels and indicates gut permeability. A blood test called LPS-binding protein (LBP) is considered the best test to determine intestinal permeability and immune activation.

Try the AIP diet

One of the most important things you can do is to consider following the Autoimmune Protocol (AIP) diet. The Autoimmune Protocol (AIP) diet is a way of eating designed to help reduce antibodies, help inflammation, and help resolve symptoms of autoimmune diseases. By reducing exposure to foods that trigger an inflammatory reaction and helping heal the gut, the AIP diet can address underlying autoimmunity.

For more information, read The Autoimmune Protocol (AIP) Diet.

## 5-day meal plan

Focus on reducing zonulin and lipopolysaccharide levels

Because zonulin and lipopolysaccharide levels are considered evidence of increased intestinal permeability, Hashimoto’s patients can incorporate ways to lower the levels. These include:

  • Take prebiotic supplements and digestive enzymes: to help balance gut bacteria.
  • Take probiotics: Recent research shows that probiotic supplements may effectively reduce zonulin and LPS levels and prevent or repair leaky gut.
  • Supplement with zinc: Low-dose zinc supplementation may improve leaky gut and reduce zonulin levels.
  • Avoid gluten: Eating gluten is a primary cause of elevated zonulin in most people, even in those who don’t have underlying celiac disease. Giving up gluten can help to reduce zonulin levels.

For more guidance on how to improve your gut health, read

A note from Paloma

Paloma’s comprehensive and holistic approach to Hashimoto’s and hypothyroidism care is one of the best ways to help ensure optimal wellness. Our thyroid-savvy providers know how best to address the autoimmune aspect of your thyroid condition and recommend various approaches to manage autoimmune disease. You can also consult a Paloma nutrition expert to help finetune your diet for gut health. Paloma Health’s free mobile app (available on iOS and Android) offers comprehensive resources to help make it easier to follow the AIP diet.


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Boelaert K, et al. Prevalence and relative risk of other autoimmune diseases in subjects with autoimmune thyroid disease. Am J Med. 2010 Feb;123(2):183.e1-9. doi: 10.1016/j.amjmed.2009.06.030. PMID: 20103030.

Lin HC, Chang HM, Hung YM, Chang R, Chen HH, Wei JCC. Hashimoto’s thyroiditis increases the risk of new-onset systemic lupus erythematosus: a nationwide population-based cohort study. Arthritis Research & Therapy. 2023;25(1). doi:

Cojocaru M, Cojocaru IM, Silosi I. Multiple autoimmune syndrome. Maedica (Bucur). 2010 Apr;5(2):132-4. PMID: 21977137; PMCID: PMC3150011.

Nancy Garrick DD. Raynaud’s Phenomenon. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Published April 10, 2017.

Serraino C. Comorbidities in Autoimmune Disease & Multiple Autoimmune Syndrome. Global Autoimmune Institute. Published December 29, 2022. Accessed June 26, 2023.

CDC - Exposome and Exposomics - NIOSH Workplace Safety and Health Topic. Published November 9, 2018.

Centanni, Marco et al. Poster 201: The “Leaky Gut” in Patients with Hashimoto’s Thyroiditis Associated with Polyautoimmunity. American Thyroid Association 2022 Annual Meeting. Thyroid, Volume 32, Supplement 1, 2022. DOI: 10.1089/thy.2022.29137.abstracts

Ramezani Ahmadi A, et al. The Effects of Probiotic/Synbiotic on Serum Level of Zonulin as a Biomarker of Intestinal Permeability: A Systematic Review and Meta-Analysis. Iran J Public Health. 2020 Jul;49(7):1222-1231. doi: 10.18502/ijph.v49i7.3575. PMID: 33083288; PMCID: PMC7548501.

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Mary Shomon

Patient Advocate

Mary Shomon is an internationally-recognized writer, award-winning patient advocate, health coach, and activist, and the New York Times bestselling author of 15 books on health and wellness, including the Thyroid Diet Revolution and Living Well With Hypothyroidism. On social media, Mary empowers and informs a community of more than a quarter million patients who have thyroid and hormonal health challenges.

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