Thyroid Disorders and Celiac

As I mentioned in my last post, celiac disease has a strong link with many other autoimmune disorders. The most common type of autoimmune disorder I work with is thyroid disorders, so I thought it was appropriate to highlight the link between thyroid disorders and celiac disease this month.  An estimated 27 million people suffer from autoimmune thyroid disorders (ATD), and about half of those are undiagnosed.

The Thyroid

The thyroid, a butterfly-shaped gland, located at the base of the neck, regulates hormones that control many functions in the body. The thyroid secretes several hormones, collectively called thyroid hormones, that influence metabolism, growth and development and body temperature. During infancy and childhood, adequate thyroid hormone is crucial for brain development.

What are Autoimmune Thyroid Disorders?

In ATD, the immune system attacks the cells in the thyroid. There are two types of ATD – hypothyroidism and hyperthyroidism.

Hypothyroidism occurs when antibodies attack the thyroid, causing it to become inflamed and enlarged. This causes the thyroid to be underactive and decreases production of thyroid hormone. Hashimoto’s thyroiditis is the most common cause of hypothyroidism.

Hyperthyroidism, typically caused by Grave’s disease, occurs in the same way, but causes the thyroid to be overactive and produces too much thyroid hormone.

Both types of ATD are diagnosed through a simple blood test. The doctor will measure the amount of thyroid stimulating hormone (TSH) in the blood to determine whether or not you have either condition. Normal values range from 0.4 – 4.0 milli-international units per liter (mIU/L). Normal value ranges may vary slightly among different laboratories. In January 2003, the American Association of Clinical Endocrinologists, recommended using a range of 0.3 to 3.0. Other groups have recommended an even tighter range with the upper level being 2.5. There is not a consensus on the upper limit, but several sources identify optimal thyroid function to have a TSH level of 1-2.

Subclinical hypothyroidism is a condition in which TSH levels are elevated, but other thyroid hormones are normal and symptoms are mild or none at all. Subclinical hypothyroidism is indicative of progression to hypothyroidism, 1 in 10 will progress to hypothyroidism within 3 years. An elevated TSH may impact your ability to lose weight, but not get you a diagnosis of hypothyroidism.

Thyroid Disorders and Celiac Disease

There is a very strong connection between celiac disease and autoimmune thyroid disorders. It is believed that individuals with celiac disease are 4 times more likely to develop ATD. Gliadin, the protein part of gluten, has a similar molecular structure to that of the thyroid gland. It is understood that when gliadin gets into the bloodstream the immune system creates antibodies to attack the gliadin. Since gliadin and thyroid cells are so similar the body also attacks the thyroid cells. Studies suggest that a gluten free diet helps improve thyroid function by reducing the autoimmune reactions in the body.

It has also been shown that celiac patients who have hypothyroidism may have poor absorption of levothyroxine, the synthetic prescription form of the hormone produced by the thyroid. So if you are someone with hypothyroidism and have not responded well to levothyroxine, it is possible you have celiac and would benefit from removing gluten from your diet. It is also possible that patients with a gluten-sensitivity, not just full blown celiac disease, may benefit from a gluten free diet to improve absorption levels.

As evidenced by the statistics, celiac and ATD are both underdiagnosed. It is also common for people to be diagnosed with one and not the other due to the overlap of symptoms and lack of cross-screening. It is thought that undiagnosed celiac disease may even cause ATD. The chart below from Today’s shows the symptoms of celiac, Hashimoto’s and Graves’.

Celiac Disease Hashimoto’s Graves’
Weight loss Weight gain Weight loss
Diarrhea and/or constipation Constipation Diarrhea
Fatigue Fatigue Fatigue
Hair loss (secondary to nutritional deficiencies) Hair loss N/A
Depression, anxiety Depression Anxiety, difficulty concentrating, nervousness
Joint or bone pain Joint pain Muscle weakness
Infertility, missed periods Infertility, missed periods Infertility, missed periods
Miscarriage Miscarriage Miscarriage

Additional symptoms of hypothryoid/Hashimoto’s are increased sensitivity to cold, dry skin, puffy face, hoarseness of the voice, elevated blood cholesterol level, and heavier than normal or irregular menstrual periods. Other symptoms of hyperthyroidism/Grave’s are rapid heartbeat (tachycardia), increased appetite, tremor — usually a fine trembling in your hands and fingers, sweating, changes in menstrual patterns, increased sensitivity to heat, difficulty sleeping, skin thinning, and fine, brittle hair.

Autoimmune thyroid disorders and other autoimmune disorders are not something that one has to accept. We have seen patients, firsthand, who are able to improve their thyroid hormones by just adapting a gluten free diet.

Other Nutritional Concerns with ATD

Beyond gluten, there are other other nutrients you want to be aware of with ATD. Iodine and selenium are essential nutrients in thyroid function. Iodine deficiency in America is very rare due to the use of iodized salt, but good food sources include fish, shrimp and seaweed. Selenium is found in seafood like lobster, crab and tuna, as well as in brazil nuts, macadamia nuts and hazelnuts. Vitamin B12 is another nutrient of concern and as many of 30% of individuals with thyroid disease are deficient. B12 is found in animal products and fortified cereals, but can also be supplemented in several forms if levels are very low.

There is a group of foods called goitrogens which naturally release a compound called goitrin when they’re broken down. Goitrin can interfere with the synthesis of thyroid hormones. Foods high in these compounds are kale, broccoli, cauliflower, cabbage and Brussel sprouts. Luckily, heating denatures most of the goitrogenic effect, so consume them lightly steamed or sauteed in moderation. Avoid having them raw if possible. Fortunately, consumption of goitrogens is typically only a concern if there is also an iodine deficiency.

Soy is another potential goitrogen. The isoflavones in soy can lower thyroid hormone synthesis. Several studies have found that consuming soy doesn’t cause hypothyroidism in people with adequate iodine stores, but soy should still be consumed in moderation and come from whole food sources such as tofu, tempeh, edamame, and soymilk. It is important to note that soy can interfere with the absorption of levothyroxine, the prescription thyroid hormone replacement, so it must be eaten at least 4 hours separate from the mediation.

As usual, the best thing to do if you suspect you have a thyroid problem, or if thyroid disorders run in your family, you should get tested and work with your doctor and dietitian to determine the best course of treatment.

Information obtained from:

Celiac Central

Today’s Dietitian – Two of a Kind — Research Connects Celiac and Thyroid Diseases and Suggests a Gluten-Free Diet Benefits Both

Today’s Dietitian – Thyroid Disease and Diet — Nutrition Plays a Part in Maintaining Thyroid Health