In functional medicine, we believe that all of the body’s systems are interconnected. When something is wrong with one system, it can show up in another one. (That’s why chasing and treating only symptoms can be frustrating – and futile!) In my functional family medicine practice, we work to understand these connections, uncover the root cause, and help the whole body heal.
Just as body systems are interconnected, sometimes diseases are also connected. For example, Hashimoto’s hypothyroidism and celiac disease are both autoimmune disorders with a potential connection.
Hashimoto’s hypothyroidism is a condition where the immune system attacks the thyroid gland, leading to an underactive thyroid and a range of symptoms such as fatigue, weight gain and depression.
Celiac disease is an autoimmune disorder where the immune system attacks the small intestine in response to gluten, a protein found in wheat, barley and rye.
Let’s take a look at this potential connection between the two diseases, including prevalence and symptoms, and what the link may mean for diagnosis and treatment.
A closer look at Hashimoto’s hypothyroidism and celiac disease
Hashimoto’s hypothyroidism is the most common cause of hypothyroidism in the United States, affecting up to 5% of the population. Women and older individuals are diagnosed with it more commonly (1).
Symptoms of Hashimoto’s hypothyroidism can vary widely, but commonly include:
- Fatigue
- Weight gain
- Depression
- Hair loss
- Cold intolerance
Diagnosis is typically made based on symptoms, thyroid function tests (TSH, free T4), and the presence of thyroid autoantibodies (anti-TPO and anti-Tg).
Treatment typically involves lifelong thyroid hormone replacement therapy.
Celiac disease is less common than Hashimoto’s hypothyroidism, affecting approximately 1% of the general population. Individuals of European descent have a higher prevalence of the disease (2).
Common symptoms include:
- Abdominal pain
- Diarrhea
- Bloating
- Weight loss
Diagnosis is typically made based on clinical symptoms, blood testing for celiac-specific antibodies and confirmation by small bowel biopsy.
The treatment plan for a patient with celiac disease usually involves a lifelong commitment to a gluten-free diet.
Exploring the link between Hashimoto’s hypothyroidism and celiac disease
There are several possible explanations for the potential connection between Hashimoto’s hypothyroidism and celiac disease.
1. Both conditions could share common genetic and environmental risk factors. For example, several genetic variants have been identified that increase the risk of both Hashimoto’s hypothyroidism and celiac disease (3, 4). Environmental factors, such as infections, stress and dietary factors, may also trigger autoimmune responses in both conditions (5).
2. Molecular mimicry is another possible link between the two disorders. Molecular mimicry is when the immune system mistakes a foreign antigen for a self-antigen, leading to an autoimmune response against both the foreign antigen and the self-antigen. For example, it is possible that the immune system may mistake gluten for a thyroid protein, leading to an autoimmune response against both gluten and the thyroid gland (6, 7).
This hypothesis is supported by several studies that have found a higher prevalence of celiac disease in patients with Hashimoto’s hypothyroidism compared to the general population (8, 9).
3. Intestinal permeability (aka “leaky gut”) is another potential mechanism linking the two disorders. Leaky gut refers to the ability of the intestinal barrier to selectively allow nutrients and other substances to pass through, while preventing the entry of harmful substances such as toxins and bacteria. In individuals with celiac disease, gluten-induced inflammation can cause damage to the intestinal barrier, leading to increased intestinal permeability (10).
Studies have also shown that individuals with Hashimoto’s hypothyroidism may have leaky gut caused by chronic inflammation and altered gut microbiota (11, 12). This increased intestinal permeability may allow gluten peptides and other antigens to move into the bloodstream, triggering autoimmune responses in both the thyroid gland and the small intestine (13).
What this means for diagnosis and treatment
Given the potential connection between Hashimoto’s hypothyroidism and celiac disease, healthcare practitioners should consider screening patients with thyroid dysfunction for celiac disease, and vice versa.
While the diseases may be connected, treatment involves different approaches: Thyroid hormone replacement therapy is the mainstay of treatment for Hashimoto’s hypothyroidism, while the treatment of celiac disease involves lifelong adherence to a gluten-free diet.
Yet the treatment for one disease may actually benefit the other. Some studies have suggested that thyroid hormones may play a role in the management of celiac disease, as they may help to reduce inflammation and improve intestinal barrier function (14, 15). And other studies have suggested that a gluten-free diet may improve thyroid function in patients with Hashimoto’s hypothyroidism (16).
Putting all the pieces together
Understanding how your body systems (and the diseases that affect the body) are connected is an important first step in taking a holistic approach to healing. If you’d like to discuss this approach, please get in touch. I’m seeing patients at Evoke5, my functional medicine clinic in Oklahoma City, as well as offering online consultations for clients across the country.
References:
- Garber JR, Cobin RH, Gharib H, et al. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocr Pract. 2012;18(6):988-1028.
- Ludvigsson JF, Leffler DA, Bai JC, et al. The Oslo definitions for coeliac disease and related terms. Gut. 2013;62(1):43-52.
- Wang Y, Yan Y, Yang F, et al. Association of PTPN22 rs2476601 polymorphism with autoimmune diseases: a systematic review and updated meta-analysis. Autoimmunity. 2019;52(2):83-96.
- De Leo S, Lee SY, Braverman LE. Hyperthyroidism. Lancet. 2016;388(10047):906-918.
- Vojdani A, Tarash I. Cross-reaction between gliadin and different food and tissue antigens. Food and Nutr Sci. 2013;4:20-32.
- Rodrigo L, Celiac disease. World J Gastroenterol. 2006;12(42):6585-6593.
- Ch’ng CL, Jones MK, Kingham JG. Celiac disease and autoimmune thyroid disease. Clin Med Res. 2007;5(3):184-192.
- Elfström P, Montgomery SM, Kämpe O, Ekbom A, Ludvigsson JF. Risk of thyroid disease in individuals with celiac disease. J Clin Endocrinol Metab. 2008;93(10):3915-3921.
- Freeman HJ. Endocrine manifestations in celiac disease. World J Gastroenterol. 2016;22(40):8472-8479.
- Fasano A. Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer. Physiol Rev. 2011;91(1):151-175.
- Di Domenicantonio A, Pierdomenico M, Degirolamo C, et al. Increased intestinal permeability and NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome expression in patients with Hashimoto’s thyroiditis. J Clin Endocrinol Metab. 2020;105(6):dgaa189.
- Corazza GR, Valentini RA, Andreani ML, et al. Gluten sensitivity in Hashimoto’s thyroiditis. Clin Endocrinol (Oxf). 2002;56(6): 699-700.
- Fasano A, Shea-Donohue T. Mechanisms of disease: the role of intestinal barrier function in the pathogenesis of gastrointestinal autoimmune diseases. Nat Clin Pract Gastroenterol Hepatol. 2005;2(9):416-422.
- Sategna-Guidetti C, Bruno M, Mazza E, et al. Autoimmune thyroid diseases and coeliac disease. Eur J Gastroenterol Hepatol. 1998;10(11):927-931.
- Sategna-Guidetti C, Volta U, Ciacci C, et al. Prevalence of thyroid disorders in untreated adult celiac disease patients and effect of gluten withdrawal: an Italian multicenter study. Am J Gastroenterol. 2001;96(3):751-757.
- Sategna-Guidetti C, Bruno M, Mazza E, et al. Gluten-free diet and autoimmune thyroiditis in patients with celiac disease: a prospective controlled study. J Clin Endocrinol Metab. 2001;86(3):104-107.