There’s a lot of misinformation out there about the best diet for Hashimoto’s. You don’t have to look hard to find supplements, random dietary restrictions, and promises that a certain diet can ‘reverse’ your Hashimoto’s in a matter of weeks. But is there a specific diet for Hashimoto’s? Which nutrients are people with Hashimoto’s likely to be deficient in?
It’s time to see what the science says about all of it.
What is the Thyroid?
Your thyroid is a butterfly shaped gland located on the front on your neck. Although it’s fairly small, it has the huge job of producing the hormones – T3 (thiiodothyronine) and T4 (thyroxine) – that regulate your metabolism. It also produces calcitonin, which controls calcium and phosphorous levels in your blood and helps with bone production.
TSH, or thyroid stimulating hormone, signals to the thyroid to release T3 and T4. TSH is made in the pituitary gland, which is inside the brain.
T3 and T4, through metabolic rate, affect the following:
Growth and development in children
Regulation of body temperature
Heartbeat
How quickly you process food
Weight, through the regulation of energy expenditure
About 12% of the U.S. population will have thyroid issues in their lifetime. Women are five to eight times more likely than men to have thyroid disorders, and up to 60% of people with thyroid issues aren’t aware of them.
What Causes Hypothyroidism?
Hypothyroidism, otherwise known as ‘underactive thyroid,’ is when your thyroid doesn’t produce enough T3 and T4.
Since T3 and T4 are responsible for the above functions, when you don’t have enough of these hormones, you can feel some distinct symptoms. They include:
Always feeling cold
Weight gain
Slow heartbeat
Dry skin and brittle nails
Feeling tired all the time
Constipation
Hair loss
Depression
Poor memory
Impaired fertility
People with hypothyroid have an increased risk for heart disease and elevated cholesterol, as well as peripheral neuropathy, which is nerve damage. Chronic hypothyroid can also cause infertility, and mental health issues.
Hypothyroid can be caused by thyroid removal surgery, some medications, cancer treatment, or pregnancy. It can also be caused by issues with the pituitary gland, which secretes TSH, which in turn causes the release of T3 and T4. This is called, ‘secondary thyroid disease,’ because it originates in another gland, rather than the thyroid itself. But most often, hypothyroid is caused by a disease called Hashimoto’s thyroiditis.
What is Hashimoto’s Thyroiditis?
Hashimoto’s is an autoimmune disease in which the immune system attacks the thyroid, causing inflammation and hypothyroid. You can have Hashimoto’s and not notice anything at all for years, or, you might notice symptoms of hypothyroid. You’re at a higher risk for Hashimoto’s if you have other autoimmune diseases such as lupus, sjogren’s syndrome, or rheumatoid arthritis.
Leaving Hashimoto’s untreated for a long period of time can cause permanent damage to the thyroid.
It’s important to note that like other autoimmune diseases, Hashimoto’s is neither caused by nor cured with diet.
What Should I Eat for Hashimoto’s?
There are some important considerations for people who have Hashimoto’s. Most centre around the fact that these individuals are more likely to be deficient in certain nutrients, or may suffer effects from eating too little (or too much) of some.
Iodine
The thyroid uses iodine, a trace element, and tyrosine, an amino acid, to make T3. So iodine, which is a mineral found in food like fish and seafood, grains, and dairy products, as well as iodized salt.
The RDA for iodine is 15 micrograms per day, except with pregnancy, when it’s 220 micrograms, and 290 micrograms for lactating women.
Iodine deficiency is fairly rare, but it wasn’t always that way. Landlocked populations in the U.S. – especially near the Great Lakes and in the mountains – that didn’t have access to the ocean and seafood saw more iodine deficiency. Iodine was added to our table salt in 1924 to mitigate this issue. 88% of households worldwide now use iodized salt.
When a person doesn’t get enough iodine in their diet, the thyroid can’t synthesize T3 and T4, leading to hypothyroidism.
But if you have Hashimoto’s, consuming too much iodine can actually make your hypothyroid worse. Some foods, like kelp and seaweed (like those seaweed snacks) can be super-high in iodine, and iodine-containing supplements are not a good idea.
Other iodine-containing foods, like shrimp, eggs, and dairy, are important to keeping your thyroid healthy – even with Hashimoto’s. The trick is the balance, not to cut iodine foods from your diet.
Selenium
Selenium is a trace mineral that you may have heard of in relation to immunity, but it’s also used by the body to make an enzyme that activates thyroid hormones.
The recommended daily intake of selenium is 55 micrograms a day, and selenium deficiency in North America is rare.
Selenium is found in seafood, meat, eggs, grains, and Brazil nuts, which contain the most selenium per gram than any other food. Just one Brazil nut a day gets you your required selenium!
Being chronically low in selenium may cause hypothyroid.
Some studies have found that selenium supplementation in people with Hashimoto’s reduces the levels of thyroid antibodies (a good thing), but it’s important to note that some of these people may have been selenium deficient to begin with. And really, the evidence for selenium supplements is lacking, but that doesn’t mean that you don’t need selenium for thyroid function.
Make sure to eat selenium-rich foods daily.
Goitrogens
A lot of people with Hashimoto’s have heard that they shouldn’t eat raw crucifers like broccoli, kale, turnips, cabbage, and Brussels sprouts, as well as soy foods. These foods are called goitrogens, and they’re known to interfere with the uptake of iodine by the thyroid. This can make your iodine levels low.
The second half of the story, though, is that only people who are already low in iodine need to worry about goitrogens. If your iodine levels are good, you can eat pretty much any food that’s classified as a goitrogen, and not worry about it. Cooking goitrogens also denatures the compounds in them that cause issues with iodine uptake.
Millet, a grain, is the one goitrogenic food that can cause issues with iodine uptake in the thyroid, regardless of your iodine levels. Stay away from it.
Vitamin D
There seems to be a link between vitamin D and Hashimoto’s.. In people with low vitamin D levels, there appears to be a negative correlation with the severity of their disease.
We don’t really know the mechanism behind this, though.
Still, it’s always a good idea for everyone to get a baseline vitamin D level, and to eat plenty of D-containing foods like dairy, fish, and egg yolks.
D supplementation might be worthwhile if you don’t get enough vitamin D from your diet (1000IU is good), and/or you live in a cold climate.
Gluten
There may be some connection between celiac disease and thyroid disease, including Hashimoto’s. But if you don’t have celiac or gluten sensitivity, there is no compelling research that shows the benefits of a gluten-free diet for thyroid issues.
I’ve seen a ton of alternative professionals (and even some RDs) telling everyone with Hashimoto’s to avoid gluten. I don’t agree with blanket recommendations, but preliminary research now suggests that a gluten-free diet may improve thyroid function and inflammation. That being said, researches concluded that more research is needed on this subject.
Foods to Avoid for Hashimoto’s
I wouldn’t say there’s any particular foods you need to avoid (besides millet). But coffee, fiber, and calcium can interact with some thyroid medications, so avoid taking them together.
There are people online selling ‘natural’ thyroid medications like dessicated thyroid made from animal thyroids. ‘Natural’ doesn’t mean ‘better,’ though. This supplement has a mix of T3 and T4 which may not be optimal for you, and unregulated supplements may not contain the ingredients they claim to have. Some people find that dessicated thyroid is easier to tolerate than Levothyroxine, and for some it really does work, especially in combination with conventional therapy. But it’s important to consider the risks before taking these supplements.
There is no diet that can cure Hashimoto’s, even if quack doctors say so. But eating a diet that’s nourishing physically and emotionally, while being rich in the above nutrients, may help optimize health and thyroid function.