Foods to Eat (and Avoid) for Thyroid Hormones

The thyroid gland may be small, but it has a powerful influence on all aspects of health – from energy production and hormone balance, to metabolism and digestion. 

Nutrition is one of the most important, and often overlooked, foundations of thyroid function. The foods you eat can either provide the nutrients needed to support thyroid hormone production and conversion or contribute to factors that make it more difficult for the thyroid to function optimally. Let’s explore the different foods in each of these categories to help you restore your thyroid function.

 

Foods That Fuel Thyroid Activity

Eating certain foods daily can help bolster thyroid hormone production as well as thyroid hormone (T4-to-T3) conversion. Incorporate as many of the following into your daily or weekly rotation for optimal thyroid support!

 

1. Antioxidant-Rich Foods

Leafy greens (except spinach), dark berries, citrus fruits, olive oil, ginger, green tea, camu camu powder

*Leafy greens: arugula, spring mix, dandelion greens

*Dark berries: blueberries, blackberries, pomegranate, cherries

Antioxidant-rich foods help protect thyroid tissue from oxidative stress and free radical damage while supporting healthy cellular energy production. Interestingly, free radicals, including hydrogen peroxide, are naturally generated during the process of producing thyroid hormones, making the thyroid particularly vulnerable to oxidative stress. When oxidative stress becomes excessive, it can disrupt both thyroid hormone production and the conversion of inactive T4 into the active thyroid hormone, Free T3. Consuming antioxidant-rich foods can help maintain this balance and support optimal thyroid function.

 

2. Sulfur-Rich Foods

Onions, garlic, cooked cruciferous vegetables

*Cruciferous vegetables: broccoli, cauliflower, kale, brussels sprouts, cabbage, etc.

Sulfur is an essential mineral that supports the body’s natural detoxification pathways and the production of glutathione, often referred to as the body’s “master antioxidant.” Glutathione helps protect the thyroid from oxidative stress and supports deiodinase enzyme activity, which converts inactive T4 into active T3. Because much of this conversion occurs in the liver and gut, efficient detoxification and healthy function of these organs are essential for optimal thyroid hormone activation.

 

3. Selenium-Rich Foods

Brazil nuts

Selenium is one of the most important minerals for thyroid health because it is required for the enzymes that convert inactive T4 into active T3. Selenium also has antioxidant properties, and helps reduce oxidative stress and inflammation. It’s incredibly important to combat autoimmune-related oxidative stress within the thyroid gland.

 

4. Iodine-Rich Foods

Kelp granules, seaweed, dulse

Iodine is an essential building block used to create thyroid hormones. In fact, the numbers in the names of the thyroid hormones (T4 and T3) refer to the number of iodine molecules used to create the hormone itself. However, iodine is what we consider a “goldilocks” mineral, and intake should be balanced since both deficiency and excess iodine can negatively affect thyroid function. Food sources such as kelp or dulse seasoning, or rehydrating dried seaweed to make a seaweed salad, are great ways to increase iodine consumption. Be sure to avoid combining iodine-rich foods with sources of goitrogens, such as raw cruciferous vegetables, as these can impair iodine absorption.

 

5. Iron-Rich Foods

Grass-fed red meat, lentils, chickpeas, cannellini beans

Iron is also required for thyroid hormone production and healthy oxygen delivery throughout the body. Low iron levels can impair thyroid hormone production and contribute to symptoms often associated with hypothyroidism, including fatigue, hair loss, and poor exercise tolerance. In addition to consuming plenty of iron-rich foods, it’s also important to support iron storage within the body through supportive nutrients like copper and vitamin A.

 

6. Retinol-Rich Foods

Beef liver, ancestral blend meats, full fat grass-fed A2 dairy

Retinol, the active and bioavailable form of vitamin A, plays an important role in thyroid hormone signaling and sensitivity of thyroid receptors, which helps support healthy TSH (thyroid stimulating hormone) regulation and improve the body’s response to thyroid hormones. Retinol (vitamin A) is also key for storing iron within the body as ferritin.

 

7. Resistant Starch

Green unripe bananas, potato starch, cooked and cooled potatoes

Resistant starch acts as a prebiotic fiber that feeds beneficial gut bacteria and promotes the production of anti-inflammatory short-chain fatty acids in the gut. By supporting gut health and reducing inflammation, resistant starch may improve the absorption of key nutrients needed for thyroid hormone production. Unlike traditional starches, resistant starch behaves more like fiber and produces a more stable blood sugar response, helping support metabolic health and reduce inflammation. This is especially important in a low T3 state, where impaired glucose regulation and blood sugar instability are common.

 

8. Fermented Vegetables

Kimchi, sauerkraut, pickled vegetables

Fermented foods are a great source of beneficial bacteria, Lactobacillus, that help support a healthy gut microbiome. Because the gut plays a key role in nutrient absorption, immune regulation, and thyroid hormone conversion, improving gut health can have a meaningful impact on thyroid function.

 

9. Omega-3 Rich Foods

Salmon, sardines, chia seeds, flax seeds, walnuts, and grass-fed beef

Anti-inflammatory omega-3 fats help regulate inflammation throughout the body. By lowering inflammation, especially chronic inflammation, we can improve thyroid hormone signaling, immune balance, and create a healthier environment for optimal thyroid function. Omega-3 fats are called essential fatty acids because we need to consume them through food or supplements, since our bodies cannot produce them. 

 

10. Demulcent Foods and Herbs

Aloe vera, marshmallow root, and slippery elm

Demulcent herbs help soothe and support the integrity of the gut lining. A healthier gut barrier can reduce immune overactivation, improve nutrient absorption, and support the body’s ability to maintain optimal thyroid hormone production and conversion. Increased intestinal permeability, or “leaky gut,” contributes to ongoing immune activation and has been linked to thyroid antibody production and Hashimoto’s thyroiditis. Supporting gut barrier health therefore plays an important role in promoting both thyroid and immune health.

 

11. Chelating Herbs

Parsley, cilantro, and chlorella 

Chelating herbs contain compounds that help support the body’s natural detoxification and elimination of certain environmental toxins and heavy metals. Reducing toxic burden may decrease a significant source of stress on the thyroid and support healthier hormone production and cellular function.

 

12. Bitter Foods

Arugula, beets, citrus rind, green tea, and dandelion greens

Bitter foods help stimulate digestion, bile flow, and liver function. The liver plays a major role in converting T4 into active T3 and clearing excess hormones, therefore supporting liver health also significantly influences thyroid function.

 

Foods That Block Thyroid Function

Other foods can notably block thyroid function itself, or block factors that directly affect thyroid hormone production and conversion. Limit these foods as best as possible to support optimal thyroid activity.

 

1. Goitrogenic Foods

Raw cruciferous vegetables, soy products (edamame, soybean oil, soy protein, soy milk)

Raw cruciferous vegetables and soy-based foods contain compounds called goitrogens that can interfere with iodine uptake by the thyroid gland. This specifically happens when iodine levels are already low, which is a common finding in our practice. Recall that iodine is an essential component of thyroid hormones. Goitrogen content is decreased by cooking cruciferous vegetables, but it’s important to avoid excessive intake, especially if you have low iodine levels or existing thyroid dysfunction.

 

2. Gluten

Wheat, barley, rye, beer, malt beverages (including hidden gluten in soy sauce, teriyaki sauce, salad dressings, marinades and gravies)

For many individuals, particularly those with autoimmune thyroid conditions, gluten can contribute to increased intestinal permeability and immune activation. This drives chronic inflammation and can increase thyroid antibody activity. Research shows positive impacts on thyroid autoimmunity with the removal of gluten, namely a reduction in TPO thyroid antibodies and improvement in thyroid hormone production.

 

3. A1 Dairy

Cheese, milk, or yogurt from A1 cows (choose dairy from goat, sheep, or A2 cows instead)

A1 casein is the primary protein found in conventional cow’s milk dairy products. Some people experience increased immune reactivity, digestive symptoms, and inflammation in response to A1 dairy. Switching to goat, sheep, or A2 dairy products can help decrease inflammation and support thyroid health in sensitive individuals.

 

4. Hydrogenated Vegetable Oils and Excess Omega-6 Fats

Sunflower oil, canola oil, palm oil, peanut oil, soybean oil, soy lecithin, tofu

Highly processed vegetable oils are rich in omega-6 fatty acids and may contribute to chronic inflammation when consumed in excess compared to omega-3 fatty acids. Producing these oils often relies on chemical extraction with hexane, a toxic chemical that can impact the nervous system with chronic exposure. Once again, increased inflammation negatively affects thyroid hormone signaling, cellular energy production, and overall metabolic health.

 

5. High-Oxalate Foods

Spinach, almond flour, almond butter, rhubarb, rice bran

Oxalates are a type of “anti-nutrient” that bind to beneficial minerals such as calcium, magnesium, and iron in the digestive tract, effectively reducing their absorption. Excessive oxalate intake may contribute to nutrient deficiencies, particularly minerals that play important roles in thyroid function. Interestingly, mold mycotoxin exposure has been shown to increase oxalate production within the body, creating an additional burden on detoxification pathways, mitochondrial function, and thyroid activity. This combination contributes to all four types of energy leaks that impair thyroid hormones.

 

6. High-Mycotoxin Foods

Peanuts, cashews, pistachios, wheat, corn, barley, coffee (unless mycotoxin tested)

High-mycotoxin foods are those that are at considerably higher risk of mold mycotoxin contamination. In addition to worsening inflammation and immune dysregulation, mycotoxin exposure increases oxidative stress and mitochondrial dysfunction, indirectly impacting thyroid hormone utilization and energy production. High mycotoxin load within the body can act as a significant energy leak, diverting resources away from thyroid hormone production and conversion.

 

7. Halogens

Potassium bromate (in many processed breads and pastries), BVO (in many beverages), table salt, tap water, fluoridated water, black tea, canned meats

Halogens such as bromine, fluoride, and chlorine can compete with iodine for uptake into thyroid tissue. Excessive exposure can interfere with thyroid hormone production by limiting the thyroid gland’s ability to utilize iodine efficiently in the process of producing thyroid hormones.

 

8. High Heavy Metal Foods

Brown rice, plant-based protein powder, tuna, king mackerel, shark, swordfish, dark chocolate, dried herbs

The accumulation of heavy metals such as mercury, arsenic, cadmium, and lead within body tissues increases overall toxic burden and can disrupt thyroid hormone production, conversion, and receptor function. Limiting common dietary sources of heavy metals may help reduce toxic burden on the liver and support healthier thyroid function.

 

9. Smoked and Grilled Meats

Frequently consuming heavily smoked, charred, or grilled meats may increase exposure to inflammatory compounds such as polycyclic aromatic hydrocarbons (PAHs) and advanced glycation end products (AGEs). These compounds can increase oxidative stress and may contribute to mitochondrial dysfunction that impacts thyroid health over time.

 

Our Functional Approach to Improve Thyroid Hormones

While no single food can fix thyroid hormone dysfunction, nutrition plays a powerful role in supporting thyroid hormone production, conversion, and cellular responsiveness. By prioritizing nutrient-dense foods that fuel thyroid hormone production and minimizing common dietary factors that may interfere with it, you can create a stronger foundation for energy, metabolism, hormone balance, and overall health.

Inside our self-paced course, Functional Thyroid Foundations, we guide you through the nutrition and exercise principles that help support optimal thyroid hormone production. You’ll receive easy-to-follow resources including recipes, meal plans, workouts, supplement recommendations, brand guides, grocery shopping lists, access to an exclusive private podcast feed, and more.