What is a goitrogen?
Goitrogens are substances that cause the thyroid to enlarge forming a “goitre”. They may be foods, pharmaceutical drugs (eg, lithium) or chemicals in environmental pollution.
How do they affect the Thyroid?
They can affect the thyroid’s ability to produce metabolism regulating hormones, by interfering with iodine metabolism. This causes the pituitary gland to release thyroid stimulating hormone which may cause the thyroid to eventually lay down more cells in an effort to increase its production of hormones, leading to an enlarged thyroid or “goitre”.
Should we stop eating Goitrogens?
While it could be a good idea to minimise goitrogens in those who have a thyroid condition it’s not necessary to avoid all of them all of the time. Keeping the foods that are high in goitrogens to a minimum, and also eating them cooked, steamed or fermented, will help reduce exposure to goitrogens.
Also getting enough iodine by eating plenty of iodine rich foods such as; seafood, seaweed, yoghurt, cow’s milk and eggs, will help reduce the impact goitrogens will have on thyroid function.
There are so many wonderful nutrients in these foods, that I wouldn’t advocate cutting them out altogether.
Foods that have a high Goitrogenic effect on the thyroid;
- Bok Choy
- Broccoli
- Brussel sprouts
- Cabbage (including sauerkraut and kimchi)
- Cauliflower
- Kale
- Kohlrabi
- Mustard and Mustard greens
- Radishes
- Swedes
- Soy (soy isolates, soy milk and tofu)
- Turnips
Foods that have a lower Goitrogenic effect on the thyroid;
- Almonds (raw)
- Asparagus
- Bamboo shoots
- Cashews (raw)
- Flaxseeds (linseeds)
- Peaches
- Peanuts (raw)
- Pears
- Pine Nuts
- Pumpkin seeds
- Radishes
- Spinach
- Strawberries
- Sweet Potatoes
- Walnuts (raw)
Steaming, cooking and fermenting all of these foods reduces goitrogenic substances considerably.
Foods that support thyroid function;
Iodine rich foods;
- Seafood is the richest source of iodine, particularly salmon, tuna, cod, oysters and prawns
- Seaweed and other sea vegetables; crumble up Nori seaweed sheets over a salad or in a stew
- Lima Beans
- Prunes
- Eggs
- Fennel
- Jerusalem Artichokes
- Raisins
Antioxidant rich foods
Foods rich in selenium, zinc and vitamins such as C and A are naturally high in antioxidants which help to reduce free radicals (damaging elements caused by oxidative stress).
Antioxidants reduce inflammation and as most thyroid issues are affected by inflammation, it is particularly important to keep inflammation down. Free radicals are also produced when the thyroid processes iodine (by producing hydrogen peroxide).
Foods that are high in antioxidants include;
- Brightly coloured berries; blueberries, blackberries, mulberries, raspberries and strawberries.
- Brazil nuts – high in selenium. 1 large or 3 small Brazil nuts are enough for your daily selenium needs. Be careful not to overdo it as selenium is toxic in large amounts.
- Capsicums, tomatoes and citrus fruits for vitamin C
- Carrots, pumpkin, sweet potato, dark leafy greens, broccoli, red or yellow capsicums for beta carotene. Have foods that are high in beta carotene with a source of fat, such as olive oil or nuts, as this can help improve absorption.
- Fruits such as plums, cherries, apples, peaches, nectarines, apricots and red grapes
- Dried fruits such as prunes, figs, apricots, dates and raisins.
- Herbs and spices such as cinnamon, turmeric, coriander, cumin, basil, parsley, oregano and dill.
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