The Celiac and Autoimmune Thyroid Disease Connection

There is a relationship between autoimmune thyroid disease (AITD) and celiac disease. Celiac disease is an autoimmune disorder that causes inflammation and damage in the lining of the intestine after eating gluten, a protein found in wheat, rye, and barley. And AITD includes thyroid conditions that are caused by the body's immune attack against the thyroid gland, most commonly Hashimoto's thyroiditis or Graves' disease.

The Risk Relationship

The risk of celiac disease is substantially higher for people who have AITD. And people who have celiac disease are four times more likely to have AITD.

Given these risks, some experts recommend that patients with each condition should be routinely screened for the other.

AITD and celiac disease have a few commonalities, including sharing some of the same genes, a higher risk for other autoimmune conditions, and even some of the same symptoms.

Shared Genes

While it's still unclear exactly why celiac disease and AITD often occur together, at least some of the explanation seems to be that they share specific genes.

The gene variants DR3–DQ2 and/or DR4–DQ8 predispose to celiac disease and to AITD. Other specific genes, including CTLA-4, the HLA genes, and PTPN22, are found in celiac disease and AITD as well.

Higher Risk of Other Autoimmune Diseases

People with celiac disease and/or AITD are also more likely to develop other autoimmune conditions, like type 1 diabetes, Addison's disease, rheumatoid arthritis, lupus, Sjögren's syndrome, and autoimmune hepatitis.

Shared Symptoms

Celiac disease shares some symptoms with both forms of AITD, Hashimoto's thyroiditis (HT) and Graves' disease (GD).

Interactions Between Thyroid and Gluten

Studies show that celiac disease and/or gluten may affect how your thyroid functions.

For instance:

• The tTG antibodies found in celiac disease may contribute to thyroid dysfunction by binding to thyroid cells.
• If you have celiac disease along with a mild form of hypothyroidism called subclinical hypothyroidism, following a strict gluten-free diet for a year may bring your thyroid hormone levels back to normal.

The Role of a Gluten-Free Diet

Research is unclear as to whether or not implementing a gluten-free diet is helpful when you have AITD but not celiac disease. Experts do note that eliminating gluten can help reduce inflammation in your gut, a problem for many AITD patients.

And, some studies have shown that thyroid antibodies, which are common in AITD, decrease after implementing a gluten-free diet. For instance, in a 2018 study, 34 women with AITD were divided into two groups; one was put on a gluten-free diet and the other was not. After six months, the women on the gluten-free diet had reduced levels of thyroid antibodies while the other group had no noticeable change.

Gluten-Free Diet Benefits

If you're diagnosed with celiac disease, your healthcare provider will treat it by putting you on a lifelong gluten-free diet.

Going on a gluten-free diet can have these benefits:

• It helps your intestines heal, allowing better absorption of your thyroid hormone replacement medication.
• You may eventually need less of your medication due to better absorption.
• There's the potential for weight loss.
• Your celiac disease symptoms like fatigue, weight loss, constipation, diarrhea, joint pain, depression, and anxiety will likely decrease.
• You may feel healthier overall.
• Your thyroid inflammation may be reduced.
• Your body may be able to better absorb nutrients.

Gluten-Free Diet Drawbacks

Though some people eliminate gluten for weight loss and other purposes, little research has been conducted on whether or not a gluten-free diet is a good choice for those who don't have celiac disease or gluten sensitivity.

Disadvantages of a gluten-free diet include:

• Gluten-free foods tend to be more expensive.
• You're no longer getting many of the vitamins and nutrients found in gluten like calcium, iron, folate, thiamin, and fiber, so you'll have to get them in other foods and/or by taking supplements.
• It can be difficult to follow.
• You need to read labels carefully, both to avoid gluten and to make sure you're not getting too much sugar or fat, which tends to replace gluten in some products.

A Word From Verywell

If you think you may have symptoms of celiac disease or thyroid disease, talk to your doctor. These conditions can be managed to reduce symptoms and prevent complications.