If you have been diagnosed with hypothyroidism, it can be really difficult to know what to eat to support your symptoms. One thing that many people aren’t aware of is that there are also certain foods you may need to avoid if you have low thyroid.
Firstly, soy is one of the most common allergens and food sensitivities. It’s important for anyone with low thyroid to rule out food sensitivities because they can lead to inflammation, which can make low thyroid worse.
Soy is also a goitrogen, but the story with soy, as it relates to hypothyroidism, is a little more clear than with cruciferous veggies. In rat studies, soy has been found to block the activity of the TPO enzyme, and has therefore been linked to the development of autoimmune thyroiditis. Studies have also shown that soy can increase TSH levels, and contribute to low thyroid, especially if consumed over the long-term. This is not to say that soy causes low thyroid, but that someone with low thyroid may be better off avoiding soy.
Gluten can be problematic for a few reasons. Gluten activates a protein called zonulin, which leads to increased intestinal permeability, commonly referred to as ‘leaky gut”. This creates an environment where undigested particles, toxins and bacteria can pass through the gut lining into the bloodstream and lead to inflammation and food sensitivities. As I mentioned earlier, chronic inflammation can make low thyroid worse. Even if you don’t have low thyroid, chronic inflammation can also lead to an overactive immune system, which can contribute to autoimmune disease.
The second part to this relates to Hashimoto’s, which is an autoimmune version of hypothyroidism. The protein structure of gluten closely resembles the protein structure of the thyroid tissue, so studies suggest that continuing to eat gluten can actually lead your body to attack the cells of the thyroid, making symptoms of Hashimoto’s much worse. Interestingly, the rates of celiac disease are estimated to be four times higher in those with Hashimoto’s than the general public.
If you have low thyroid you may have been told to avoid cruciferous vegetables. Cruciferous veggies are some of the healthiest veggies out there, and include broccoli, brussels sprouts, cabbage, kale, and more. They are also considered goitrogens, which are substances that can disrupt the production of thyroid hormones by interfering with iodine uptake in the thyroid gland (iodine is needed for thyroid hormone production).
The concern with cruciferous veggies stemmed from early animal studies, which found that high consumption of them was found to cause hypothyroidism (low thyroid). However, research on humans seems to show that cruciferous veggies do not appear to contribute to hypothyroidism unless you have iodine deficiency. For the majority of people, the benefits of cruciferous veggies far outweigh the risk. We will usually suggest that people who are very low thyroid eat mainly cooked cruciferous veggies because cooking lessens their goitrogenic properties, and just be mindful not to over consume them (i.e. no more than 1/2 cup per day).
There are certain foods that may interfere with the absorption of some thyroid medications. Some examples include coffee, high fat foods, grapefruit and even fiber. It’s important to consult with your doctor about what those foods are.
If you’ve been newly diagnosed with hypothyroidism, it can be really difficult to know how food influences your symptoms. When we work with clients one-on-one, we’ll have them complete a very detailed intake questionnaire, food journal, and review any blood work they’ve had done, so we can get the full picture of any factors that may be influencing their symptoms.
If we suspect that food sensitivities or intolerances are a factor, we’ll also recommend testing for those, since the inflammation caused by food sensitivities can make low thyroid worse. Removing foods to which you’re intolerant or sensitive, like dairy for example, can actually help to alleviate symptoms. This will help us put together a plan that is unique to you, so we can avoid needlessly removing foods, especially healthy foods. Many of our clients come to us with an idea of what they “should” do, but need a personalized plan to follow and the accountability that comes with one-on-one coaching.