I recommend a wide-ranging nutrient-dense diet for thyroid health, low in refined carbohydrates and processed foods.
Some practitioners recommend a strict gluten-free and dairy-free diet for those with Hashimoto’s, as gluten and lactose intolerance may a contributing factor in many sufferers. If this applies to you, considering avoiding these foods on a trial basis.
Most people will feel better just by reducing refined carbs, especially grains, and this is more sustainable for them. This helps to stablise blood glucose levels, reduces the risk of insulin resistance/metabolic syndrome, helps keep your weight down and energy levels good. Avoid a low protein diet if you have low thyroid function, as protein helps to increase metabolism and the amino acid tyrosine is an essential precursor of thyroid hormones.
Some essential nutrients for thyroid health are listed, which can be found broad diet that includes fish and seafood, meat, nuts, seeds, eggs, dairy, pulses and plenty of fresh veg:
- Iodine and selenium (see below)
- Zinc
- Iron
- Vitamin B12
- Vitamin D (best acquired from the sun, but supplement during winter)
Iodine and selenium
Two key trace minerals needed for thyroid health are iodine and selenium. Iodine is a key ingredient of thyroid hormones; selenium has a number of roles in thyroid health including as an antioxidant and helping to covert T4 to the active form T3.
There is evidence that in the UK, teenage, young and pregnant women are at risk of iodine deficiency. Given this, it is likely that many of us have suboptimal levels, particularly given the interference from thyroid-disrupting chemicals in our environment (see below). Ensuring you include good dietary sources is essential, and is the safest and easiest way to take them. Mother nature provides good bioavailable forms.
High-iodine foods include:
- Fish and shellfish (e.g. haddock, halibut, cod, and scampi)
- Milk and dairy products
- Eggs and meat (esp. organ meats)
- Seaweeds (e.g. nori, kelp, kombu, wakame) are probably the best source of dietary iodine you can find
Foods high in selenium are also many of the those that are high in iodine, plus brazil nuts and cashews.
Supplementation: Bear in mind that it is possible to have too much of both of these minerals if you take supplements (and is particularly problematic if you have Hashimoto’s and/or are taking thyroxine).
A word on goitrogens
Goitrogens are substances in some foods that can interfere with the functioning of the thyroid gland and production of thyroid hormones. Some of the main ones are:
- Cruciferous vegetables – cabbage, broccoli, kale, cauliflower, etc.
- Soy and soy products
- Millet
While some practitioners recommend avoiding cruciferous veg, it’s now clear that these foods only exacerbate thyroid problems in those who are iodine deficient. Therefore there is no reason for most people to cut them out of their diet. They have wonderful nutritional benefits including antioxidant properties. Moderation is the answer, while ensuring that you are replete in iodine and selenium. Note that cooking or blanching markedly reduces goitrogen content.
With regard to soy, I suggest avoiding soy in processed foods such as soy milk, veggie burgers, etc. On the other hand, moderate amounts of traditional Asian fermented soy products, such as miso, tempeh and natto are likely to be beneficial to most.
