By: Lucia Botta, MSN, Dietetic Intern Cohort 2021-2022

Located at the base of the neck, the thyroid gland is a butterfly-shaped endocrine gland whose main job is to make thyroid hormones: thyroxine (T4) and triiodothyronine (T3). Thyroid hormones play a vital role in regulating many cellular activities in our body and help to control metabolism, regulate body temperature, and ensure that our main organs work efficiently.¹ 

Abnormal function of the thyroid gland affects 22% of the population.² When the thyroid gland fails to produce sufficient thyroid hormone to meet metabolic demands of the body, it is called hypothyroidism, or underactive thyroid. According to data from the National Health and Nutrition Examination Survey (NHANES), about 3.7% of people living in the United States have hypothyroidism.³ Hashimoto’s thyroiditis is the most common hypothyroid condition. Hashimoto’s is an autoimmune condition in which the immune system attacks the thyroid gland resulting in an overproduction of thyroid hormone which, over time, leads to a loss in the thyroid’s ability to produce adequate amounts of thyroid hormone (T4 or T3).⁴  

Today, thirteen million Americans are living with undiagnosed hypothyroidism, possibly due to the lack of symptoms experienced early on. Diagnosis of hypothyroidism includes lab results of elevated thyroid stimulating hormone (TSH), thyroid peroxidase (TPO) antibodies, and possibly abnormally low levels of thyroid hormone (T4 or T3). Symptoms include fatigue, weight gain, constipation, increased sensitivity to cold, dry skin, depression, muscle aches, reduced exercise tolerance, and irregular or heavy menses.¹ 

When thyroid hormones are low, medical providers may prescribe synthetic forms of thyroid hormone to increase lab values to optimal levels. The good news is that in addition to medication, symptoms may be improved with appropriate diet and lifestyle changes. 

Mediterranean-Style Eating Pattern 

Hashimoto’s thyroiditis involves inflammation of the thyroid gland. A diet that includes whole, minimally processed foods with less saturated fat, lower sugar, and more fiber has been shown to have anti-inflammatory properties. The Mediterranean-style pattern of eating includes a variety of whole foods and a colorful abundance of fruits, vegetables, legumes, whole grains, and healthy fats. Additionally, incorporating quality omega-3 monounsaturated fats found in wild-caught salmon, tuna, nuts, seeds, avocados, and olive oil has been shown to reduce inflammation in the body. Processed foods and oils such as soybean, corn, safflower and sunflower oils can be pro-inflammatory and should be reduced.⁶ The anti-inflammatory benefits of the Mediterranean-style eating pattern may help reduce symptoms associated with Hashimoto’s thyroiditis. 

Consider Going Gluten-Free 

There is a possible link between gluten and Hashimoto’s thyroiditis. Celiac disease is an autoimmune condition in which the dietary ingestion of gluten damages the small intestine.⁷ Preliminary research has shown that gliadin, the protein found in gluten, has a similar molecular structure to thyroid tissue so it may exacerbate symptoms when consumed.⁷ Approximately 25% of people with autoimmune diseases tend to develop an additional autoimmune disease.⁸ People with Hashimoto’s should therefore be tested for celiac disease before eliminating gluten from their diet. 

Goitrogens and Soy 

Goitrogens are substances found in the cruciferous vegetable family that, when broken down, can interfere with the production of thyroid hormone. Food sources include broccoli, cauliflower, arugula, cabbage, and kale, among others. However, one must consume an unrealistically large amount (more than 1-2 pounds!) to be concerned about the effects. It is also important to note that this is usually coupled with an iodine deficiency, which is uncommon in the United States due to our food supply and diets providing adequate amounts of iodine from iodized salt. Additionally, cooking these foods reduces the potential negative effects.⁹ Soy is also a goitrogenic food. When dietary iodine consumption is low, soy isoflavones can negatively affect thyroid function by causing excess inflammation of the thyroid gland. Again, iodine deficiency in the United States is uncommon, so soy can be included as part of a healthy diet. It is recommended to include 2-3 servings a week of soy-based foods, including miso, tofu, and tempeh. However, when soy foods are consumed at the same time as thyroid medications, absorption of the medications can be blocked. It is recommended not to consume soy products within 2-3 hours of taking thyroid medication. 

Exercise and Inflammation 

Participation in regular physical activity may have both acute and long-term anti-inflammatory benefits. Exercise and its specific role in reducing inflammation in the body can be difficult to study because the cells that initiate inflammation (i.e., macrophages) have different effects on different processes depending on the tissue they are in. For example, in adipose tissue (i.e., body fat), the expression of inflammatory markers Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNFα) coming from the macrophages are overexpressed in overweight and obese individuals. Research has shown that exercise may have a greater effect in reducing the size of adipose tissue cells compared to low calorie diets for this population. The CDC recommends 150–300 min./week of moderate or 75–150 min./week of strenuous physical activity coupled with resistance training twice a week for improved overall health benefits.¹⁰ Exercise may reduce inflammation in the body; however, individualization for duration and intensity is encouraged. 

Hashimoto’s thyroiditis can impose unique challenges to everyday life, such as difficulty regulating body temperature, unwanted weight fluctuations, and fatigue. Prioritizing healthier food choices and 30 minutes of movement daily can help relieve symptoms and improve quality of life. Working closely with your doctor and dietitian on an individualized medical and nutrition plan is a great place to start.  

Here is a recipe for a delicious salmon and vegetable stir-fry by The Roasted Root. It is packed with omega-3 fats and colorful veggies and can be served with a side of whole grain brown rice. Enjoy! 

References 

1. American Thyroid Association. https://www.thyroid.org/hashimotos-thyroiditis/ 

2. 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. Thyroid (New York, NY). 2012;22(12):12-1235. doi:10.1089/thy.2012.0205 

3. Aoki Y, Belin RM, Clickner R, Jeffries R, Phillips L, Mahaffey KR. Serum TSH and total T4 in the United States population and their association with participant characteristics: National Health and Nutrition Examination Survey (NHANES 1999–2002). Thyroid. 2007;17(12):1211–1223. 

4. Helfand M, Force USPST. Screening for subclinical thyroid dysfunction in nonpregnant adults: a summary of the evidence for the U.S. Preventive Services Task Force. Ann Intern Med. Jan 20 2004;140(2):128-41. doi:10.7326/0003-4819-140-2-200401200-00015 

5. Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement. Thyroid (New York, NY). 2014;24(12):167-1751. doi:10.1089/thy.2014.0028 

6. Mahan K, Raymond J. Krause’s Food & the Nutrition Care Process. Elsevier; 2017. 

7. Chng CL, Biswas M, Benton A, Jones MK, Kingham JGC. Prospective screening for coeliac disease in patients with Graves hyperthyroidism using anti-gliadin and tissue transglutaminase antibodies. Clinical endocrinology (Oxford). 2005;62(3):303-306. doi:10.1111/j.1365-2265.2005.02214.x 

8. Mohan MP, Ramesh TC. Multiple autoimmune syndrome. Indian journal of dermatology, venereology, and leprology. 2003;69(4):298-299.  

9. Harris C. Thyroid Disease and Diet — Nutrition Plays a Part in Maintaining Thyroid Health. Today’s Dietitian. 14(July 2012)(7):40.  

10. Metsios GS, Moe RH, Kitas GD. Exercise and inflammation. Best Pract Res Clin Rheumatol. 2020;34(2):101504. doi:10.1016/j.berh.2020.101504