Hashimoto’s thyroiditis, also known as chronic autoimmune thyroiditis, is one of the most common autoimmune conditions. In the United States, Hashimoto’s is the leading cause of hypothyroidism, or abnormally low function of the thyroid gland. Although It shares triggers with other autoimmune conditions, the thyroid’s specific nutrient needs and body-wide influences make Hashimoto’s a condition with unique nutrition considerations.
In this article, we’ll review Hashimoto’s and hypothyroidism, how symptoms can mimic several nutrient deficiencies, and why the nutrient density of foods matters. We'll also connect Hashimoto’s with the functioning of the digestive tract, why weight is not the most productive focus for managing the condition, and different diet options for support. Read on!
What Is Hypothyroidism?
The thyroid is a butterfly-shaped gland in the throat responsible for making hormones your entire body needs. Two hormones, abbreviated T4 and T3, directly impact energy metabolism in the cardiovascular, nervous, musculoskeletal, reproductive, and gastrointestinal systems. Thyroid dysfunction can cause symptoms throughout your body, increase your risk of developing other conditions, and generally lower your quality of life. (Source, Source)
Hypothyroidism can be caused by genetic and environmental factors, including nutrient deficiencies, a viral or bacterial trigger, a side effect from some medications, and possibly exposure to harmful chemicals or metals. (Source, Source, Source)
What Is Hashimoto’s Thyroiditis?
Hypothyroidism is diagnosed when thyroid stimulating hormone (TSH), which is released by the pituitary gland to signal the thyroid to produce its hormones, is abnormally high, and T4 released by the thyroid is abnormally low. Subclinical hypothyroidism is diagnosed when TSH is abnormally high while T4 hormone levels are within the normal range.
In Hashimoto’s, antibodies specific to the thyroid called thyroid peroxidase antibodies (TPO ab) and antithyroglobulin are present, with or without abnormal TSH and thyroid hormone levels. High TPO antibodies promote the gland’s destruction and lead to a decline in essential hormone production. (Source, Source, Source)
What Are the Symptoms of Hashimoto’s Thyroiditis?
Because the thyroid is involved in so many biological processes, decreased thyroid function can affect many parts of the body. Symptoms of Hashimoto’s may include fatigue, weight gain, lack of appetite, concentration problems, depression, constipation, dry skin, hair loss, slowed heart rate, cold intolerance, muscle pain, and menstrual irregularities. (Source, Source)
Thyroiditis also affects motility of the gastrointestinal tract — causing digested food to move through it more slowly — which can influence bacterial balance. Impaired motility may also increase cholesterol levels and affect blood sugar levels, bone health, and conversion of some food compounds into needed vitamins. Long-term changes in metabolic functioning from decreased thyroid function increase the risk of developing diabetes and heart diseases. (Source, Source)
What Is the Treatment for Hashimoto’s Thyroiditis?
Levothyroxine is a synthetic form of T4 that is taken by mouth when the thyroid produces insufficient amounts. While it is usually recommended as a lifelong medication, there is some evidence that up to one-third of those on levothyroxine might not need to stay on it long-term, especially if they have been diagnosed with subclinical hypothyroidism. The evidence for this is not strong, however, and more studies are needed. (Source)
Some people taking levothyroxine have normal TSH and T4 levels but still struggle with symptoms and decreased quality of life. One theory is that while levothyroxine can normalize TSH and T4 levels, not enough T4 produced this way is converted to T3, the active form needed by the body. Other possibilities include symptoms of nutrient deficiencies and gastrointestinal imbalances that commonly occur along with hypothyroidism. (Source)
Hashimoto’s Thyroiditis Diet: 6 Nutrition Principles
It may be possible to feel better with Hashimoto’s if you consider your diet as a form of medicine. In addition to taking prescribed medication when necessary, the following 6 nutrition principles can support your thyroid function, symptoms, and overall health, whether you have been diagnosed with Hashimoto’s, subclinical hypothyroidism, or hypothyroidism. (Source, Source)
Principle #1: Consider Nutrient Density
Some micronutrient deficiencies can increase the risks of developing Hashimoto’s and are connected to worsened thyroid function. Correcting deficiencies with a nutrient dense diet can improve thyroid functioning and lessen symptoms associated with poor thyroid function.
Keep in mind, though, that some nutrients essential for thyroid health are needed in relatively small amounts. Excess of some, including selenium, iron, and zinc, can have toxic side effects. Consuming micronutrients through food, rather than dietary supplements, can be the safest way to get the proper amounts. If you are concerned about deficiency, a health care professional can help you determine your needed levels.
Selenium concentrations are higher in the thyroid than in any other organ, and many of the thyroid’s proteins contain this critical micronutrient. It is a precursor to glutathione, the body's master antioxidant, which is shown to be lower in those with Hashimoto’s.
- The recommended dietary allowance (RDA) is 55 mcg per day.
- Some sources of selenium include:
- Brazil nuts (just one Brazil nut has ~70-90 mcg of selenium!)
- fish, including tuna, halibut, and sardines (amount varies)
- turkey (31 mcg/3 oz serving)
- mushrooms (20 mcg/gram)
Iron activates thyroid peroxidase, a thyroid enzyme involved in production of T3 and T4. Thyroid peroxidase is a target of TPO antibodies in Hashimoto’s. A deficiency of iron could, therefore, impair thyroid hormone production.
- The RDA of iron is 18 mg daily for premenopausal women and 8 mg for men and postmenopausal women.
- Some sources of iron include:
- fortified cereals (amount varies)
- beans (8 mg /1 cup)
- lentils (6 mg/1 cup)
- oysters (1 mg/oyster)
- organ meats (6 mg/3 oz)
- spinach (~1 mg/cup)
- molasses (1 mg/oz)
A zinc deficiency can disturb T3 and T4 levels and increase thyroid antibodies.
- The RDA of zinc is 8 mg per day for women and 11 mg for men.
- Food sources of zinc include:
- oysters (10 mg/oz)
- fortified cereal grains (amount varies)
- pumpkin seeds (~2 mg/oz)
- beef (4 mg/3 oz)
Magnesium is needed for over 300 processes in the body, including energy and antioxidant production. Magnesium deficiency can increase the risk of Hashimoto’s, and be in higher demand due to oxidative stress in those with Hashimoto’s.
- The RDA of magnesium is ~320 mg daily for women and 420 mg for men above the age of 31.
- Some sources of magnesium include:
- pumpkin seeds (156 mg/oz)
- chia seeds (111 mg/oz)
- almonds (80 mg/oz)
- spinach (78 mg/half cup)
- fortified cereals (amount varies)
- potato (43 mg/3 oz)
- brown rice (42 mg/half cup)
Vitamin D deficiencies are common among those with autoimmune diseases, and Hashimoto’s is no exception. This vitamin regulates more than 200 genes necessary for healthy physiological functioning, including thyroid function. Since sunlight is our primary source of vitamin D, many people are seasonally deficient. Repleting vitamin D levels often requires supplementation to be effective, but you should check in with your health care provider on the right amount.
- The RDA of vitamin D is 15 mcg (600 IU) daily.
- Food sources include:
- cod liver oil (34 mcg/tablespoon)
- fatty fish (mackerel, salmon; 14 mcg/3 oz serving)
- mushrooms (9 mcg in a half cup, if exposed to UV light)
- fortified cow’s milk (3 mcg/cup)
Protein needs vary individually. However, consuming an adequate amount can help support thyroid function.
- The RDA of protein per day is based on your body weight. However, other health conditions and calculation adjustments can also influence protein recommendations.
- Sources of protein include:
- meats (~7 g/oz)
- fish and seafood (~7 g/oz)
- eggs (7 g/egg)
- lentils (18 g/1 cup)
- nuts (~7 g/quarter cup)
- dairy products (8 g/1 cup milk)