Your thyroid is responsible for producing two crucial hormones – Triiodothyronine (T3) and Thyroxine (T4). These two are regulated by your Thyroid Stimulating Hormone (TSH) which is produced by the pituitary gland. TSH is what is most commonly measured via a blood test to assess thyroid health.
Why are your thyroid hormones so special? They regulate basal metabolic rate, which is the amount of energy expended at rest. Specifically, they regulate protein, fat, and carbohydrate metabolism, affecting how human cells use energetic compounds, help regulate long bone growth and are essential for proper development and differentiation of all cells of the human body. They also stimulate vitamin metabolism and regulate heat in the body. This then has a direct impact on things like your weight and sleeping patterns an cause common symptoms such as fatigue, feeling cold, constipation, dry and brittle hair, hair loss, brittle nails and memory loss.
Certain foods will nourish your thyroid while others will impact it’s overall function. Iodine is a constituent of the thyroid hormones. The thyroid gland actively absorbs iodide from the blood to make and release these hormones into the blood, actions that are regulated by TSH. Iodine is concentrated in thyroid tissue and hormones, but 70% of the body’s iodine is distributed in other tissues, including mammary glands, eyes, gastric mucosa, arterial walls, the cervix, and salivary glands.
Foods to avoid:
- Iodine binders
Goitrogenic substances bind to iodine and disrupt normal thyroid function. Studies have shown that goitrogens have a significant role in influencing iodine and brain development. Goitrogens are found in:
- Cassava, when crushed and not detoxified by soaking
- Soybeans (and soybean products such as tofu, soybean oil, soy flour, soy lecithin)
- Pine nuts
- Peanuts
- Flax seed, flax seed contains cyanide which transforms into thiocyanate inside the body leading to hypothyroid syndrome
- Millet
- Strawberries
- Pears
- Peaches
- Spinach
- Bamboo shoots
- Sweet potatoes
- Brassica family of vegetables
- Bok choy
- Broccoli
- Broccolini (Asparations)
- Brussels sprouts
- Cabbage
- Canola also known as Rapeseed
- Cauliflower
- Chinese cabbage
- Choy sum
- Collard greens
- Horseradish
- Chinese broccoli
- Kale
- Kohlrabi
- Mizuna
- Mustard greens
- Radishes
- Rapini
- Rutabagas (swedes)
- Tatsoi
- Turnips
And a few tips for consumption:
- Although these vegetables are goitrogenic, they contain important fiber, vitamins, minerals, and anti-oxidants, and they are too nutritious to completely avoid.
- Try to eat them in moderation only.
- Eat them cooked if possible – the cooking process deactivates most of the goitrogenic compounds but if a client of mine presents with a severely underactive thyroid or iodine deficiency, I limit their consumption of these foods.
- Raw green juices often includes goitrogenic vegetables like kale and these juices end up providing highly concentrated amounts of thyroid disrupting ingredients.
- Soy and millet, even when cooked do not inactivate goitrogens.
- Grains that contain gluten
New evidence has shown a link between thyroid autoimmune disease and gluten intolerance and Coeliac disease. Your body recognizes gluten as a foreign invader, sending antibodies to attack, subsequently attacking your thyroid gland as well. According to Chris Kresser, the immune response to gluten can last up to 6 months each time you eat it. This explains why it is critical to eliminate gluten completely from your diet. Being “mostly” gluten-free isn’t going to cut it. If you’re gluten intolerant, you have to be 100% gluten-free to prevent immune destruction of your thyroid. Read on here.
- Wheat
- Barley
- Bulgur
- Durham
- Farina
- Kamut
- Kasha
- Matzo Meal
- Rye
- Semolina
- Spelt
- Triticale
- Fluoride rich foods and fluids –
Researchers found that excess fluoride correlates with iodine deficiency. In fact, fluoride was used to treat an overactive thyroid in the 1950s. We consume the majority of our fluoride though toothpaste and mouth wash but we also get a lot through our drinking water and tea (make sure your tea is organic and use filtered water to steep your leaves). Foods particularly high in fluoride include non-organic fresh produce, breakfast cereals, juices and luncheon meats.
Foods to eat to boost thyroid function:
- Iodine rich foods: Read a previous blog on iodine and its richest sources – seaweed.
- Brazil nuts are very high in selenium, which is needed to convert the thyroid hormone T4 to T3. Eat 2 per day and make sure they are activated. Read here about phytic acids in food and why we need to soak or sprout our nuts and seeds.
- Tyrosine rich foods. The thyroid gland combines tyrosine and iodine to make thyroid hormone. Some good sources include pumpkin seeds, beef, fish, dairy products, eggs, bananas, avocados, poultry, and almonds.