Authored article - Thyroid Health and Nutrition: What to Eat and What to Avoid
One of the most common questions I am asked in my clinic is whether food can affect the functioning of the thyroid gland. It is a fair question, and the honest answer is yes, more than most people realise. While diet alone does not cause or cure thyroid disease, what you eat can meaningfully support or interfere with how the thyroid gland functions and how well the thyroid medications work.
What does the thyroid gland need to function?
● Iodine
The thyroid gland requires iodine to produce its hormones, thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, energy, mood, and body temperature. Without adequate iodine, the gland simply cannot do its job.
Good dietary sources include iodised salt, dairy products, eggs, and seafood. Most people eating a varied diet get enough, but those following strict elimination diets or avoiding dairy entirely may not be.
● Selenium
Selenium is also a very important micronutrient. It is a component of an enzyme that activates thyroid hormones and it protects the gland from oxidative damage. Brazil nuts are one of the richest sources of selenium, but a small amount goes a long way, one or two nuts a day is plenty. Eggs, sunflower seeds, and wholegrains also contribute meaningfully.
● Zinc
Zinc supports thyroid hormone synthesis and conversion. Many people do not get enough of it, particularly those who eat little or no meat, making it worth paying attention to in a largely vegetarian diet. Tofu, Lentils, chickpeas, pumpkin seeds, and nuts are all good plant-based sources.
Foods that can interfere with thyroid function
● Cruciferous Vegetables
Goitrogens are compounds found in cruciferous vegetables, cabbage, cauliflower, broccoli, kale, that can interfere with iodine uptake by the thyroid when consumed in very large amounts in raw form. This is frequently overstated online.
For most people with adequate iodine intake, moderate consumption of these vegetables, especially when cooked, poses no meaningful risk. I tell my patients not to avoid these nutritious foods, but not to eat them in excessive quantities in raw form either.
● Soy
Soy is another food that generates confusion. Soy-based foods can interfere with the absorption of thyroid medication when consumed too close to a dose. The standard advice is to take thyroid medication on an empty stomach and wait at least 30 to 60 minutes before eating or drinking, particularly before consuming soy, high-fibre foods, or calcium-rich foods.
● Processed Foods
Highly processed foods, excess sugar, and refined carbohydrates do not directly damage the thyroid, but they promote systemic inflammation and metabolic dysfunction, both of which can worsen thyroid-related symptoms.
There is no specific thyroid diet, and patients should be cautious of rigid elimination plans that promise to heal the thyroid through food alone. Good nutrition can support overall metabolic health, reduce inflammation, and ensure the gland has the micronutrients it needs to function well. Eat varied, minimally processed food, ensure adequate iodine and selenium, take thyroid medications as directed, and get your levels checked regularly.
