Lumps that form in the thyroid, a hormone-producing gland below the Adam's apple, are called nodules, a catch-all term encompassing many different varieties. Although usually harmless, nodules are very common -- according to the New York Thyroid Center, 50 percent of the population either has or will develop them. About a third to half shrink away spontaneously without the need for any treatment, but they should never be ignored because about 5 percent turn out to be cancerous [Resources 1]. People with celiac disease, an autoimmune condition triggered by proteins in wheat, barley and rye called gluten, are also at increased risk for autoimmune thyroid conditions and vice versa [Ref. 1]. When these occur together, some evidence suggests that eliminating gluten from the diet might also help resolve thyroid problems.
The Celiac-Thyroid Connection
Research aimed at identifying how often celiac disease and autoimmune thyroid conditions occur together have produced varying results, but a Dutch study published in the 2007 "World Journal of Gastroenterology" found that 21 percent of celiac participants tested positive for thyroid disease, while 15 percent of the group with thyroid disease tested positive for celiac disease. If the immune system deploys antibodies to attack the thyroid, the damaged gland may become underactive, a condition called Hashimoto's thyroiditis, or overactive, a condition called Grave's disease. These, celiac disease and other autoimmune disorders often run in families.
Inflammation can cause the thyroids of Hashimoto's thyroiditis patients to become enlarged, the New York Thyroid Center says, but nodules aren't usually associated with this condition. However, since Hashimoto's patients have increased risk of thyroid cancer, if a nodule is found, doctors usually perform a needle biopsy to check for malignancy. With Grave's disease, one or more nodules, often composed of hormone-producing tissue, may be present. If they become enlarged, the swelling is called a nodular goiter. A blood or fluid-filled nodule is called a thyroid cyst.
The existence of thyroid nodules doesn't necessarily mean that there's anything wrong with your thyroid function, so they may not need any treatment at all -- but only a doctor should make that call. There's no evidence to suggest that adherence to a gluten-free diet, or any other dietary modification, can shrink nodules. The American Thyroid Association emphasizes that nodules in people with autoimmune thyroid disease should always be evaluated for cancer. According to the Gluten Intolerance Group, some celiacs with autoimmune thyroid disease claim that eliminating gluten from their diets reduced their need for hormone replacement drugs. Surgical removal is the standard treatment for malignant nodules and for benign nodules that don't cause any symptoms, while watchful waiting is the treatment often preferred by doctors.
A exhaustive review of the findings of past studies into celiac disease and autoimmune thyroid disease was published in a 2007 issue of "Clinical Medicine and Research." One paper cited by the authors concluded that thyroid-related antibodies tend to disappear when celiacs with autoimmune thyroid disease went on gluten-free diets -- but other studies found that eliminating gluten made no difference. After weighing the evidence, the authors concluded that when celiac disease is diagnosed and a gluten-free diet is adopted early in life, the odds improve that celiacs will avoid developing other autoimmune disorders.