The thyroid gland makes hormones that control or are involved in every cell in the body. The foods we eat have a tremendous impact on thyroid hormone levels and the overall function of the thyroid. In most cases, thyroid diseases are often prescribed thyroid hormone replacement medication with little guidance on nutrition. So what are the best foods to eat for both an over- and underactive thyroid?
Unfortunately, in most cases, nutrition is not at the forefront to maintain optimum thyroid function. However, foods and nutrients can have a large influence on the thyroid and can be incorporated into your patients’ routines. Autoimmune protocols (AIP) involving specific foods are becoming increasingly popular for improving health and strengthening the immune system in inflammatory conditions such as psoriasis, rheumatoid arthritis, lupus, and Celiac disease.
Our genes are different, as our exposures, stressors, and susceptibilities. This means that our diet plan for thyroid patients also should be individualized based on a detailed history, with a special focus on digestive function. Digestive health is at the root of many healing processes, and the thyroid benefits tremendously from focusing on healing the gut.
This blog discusses the best food for thyroid patients. Learn how certain foods may enhance your patient’s thyroid health to improve how they feel.
How Do Foods and Nutrients Improve Thyroid Function?
Hormones depend on nutrient composition in the diet to function optimally. Nutrients are the building blocks of the hormones themselves. Foods are also able to control inflammatory processes that affect thyroid as well.
In the past, practitioners have largely ignored this aspect of hormone health. As research continues to expand about the power of food and nutrients, so does our ability to help our clients. Hypothyroidism and hyperthyroidism causes can stem from a lack of proper diet and toxin exposures.
You can use insulin sensitivity as an example of this; food is the primary driver of this hormone. Insulin has a feedback loop with thyroid as well; if your patients have insulin resistance, they likely will also have poor thyroid function (R).
Highly-processed snack foods now make up an average of 60 percent of diets in the United States. These low-nutrient foods negatively impact thyroid function (R). We sought to put together a comprehensive list of AIP snacks and foods for patients with thyroid disorders. We also provide the rationale for each food item we list in this blog.
Nutrients that Help Thyroid Function
Soil composition, stress, genetic predisposition, and existing health conditions cause many vitamins and nutrients to fall short in our diets, even when we try to eat healthy (R, R, R, R, R, R). These can include:
- Vitamin D
- Vitamin A
- Vitamin C
- Vitamin E
Many of these nutrients fall low in the Standard American Diet (R). Consider testing the blood levels of nutrients of your patients to determine the severity of deficiency present.
Some patients with hyperthyroidism, thyrotoxicosis, or radioactive iodine treatments need to have a limited iodine diet in the short-term if they are undergoing standard treatment for their disorder (R). However, in most cases of hyperthyroidism, it is best to balance out the minerals for thyroid by using the following strategies.
All patients with thyroid disorders should have their vitamin D level checked and supplemented to reduce bone loss. This is especially true for Graves’s disease and other forms of hyperthyroidism. Symptoms of hypothyroidism and hyperthyroidism can mimic nutritional deficiencies like vitamin D (R).
Make sure that adequate magnesium and other cofactors for vitamin D metabolism are included. These include vitamin K2, vitamin A, zinc, and boron (R).
Best foods for thyroid patients with a holistic nutrition perspective
Herbs & Spices
Thyroid patients’ snacks and foods should include spices and herbs daily. Why?
Daily intake of spices, including turmeric, chilies, and other spices reduced chances of goiter in an area of South Asia where goitrogens in the diet are very high (R).
Turmeric was able to reduce T3-induced enlargements of the kidney because it reduced oxidative stress in a rat study (R). Curcumin from turmeric also protected thyroid tissue from the toxic effects of fluoride in rats (R).
Antioxidants, including vitamin C, E, and turmeric protected the thyroid from damage due to chemically-induced thyroid dysfunction in rats (R)
Curcumin also may reduce thyroid cancer risk; cell study showed that curcumin reduced cancer cell growth and spread of papillary thyroid carcinoma cells (R).
Spices and herbs of all kinds are known to dampen down inflammation, which is at the root of most if not all autoimmune conditions, including Hashimoto’s thyroiditis and Grave’s disease (R).
Want an easy way to get spices into the diet? Check out these all-organic NON-GMO spice mixtures we like to use with clients for easy meal preparation.
BOTTOM LINE: spices and herbs help dampen the inflammatory response for thyroid diseases.
Some people have the misconception that iodine-rich fruits and vegetables come from eating a variety of foods. In fact, iodine comes primarily from seafood and seaweed, and very little is present in fruits and vegetables.
Here is a noncruciferous vegetable list for your thyroid patients to enjoy liberally:
- Bell peppers
- Sweet potatoes
Rich in antioxidants and complex nutritional profiles, non-cruciferous vegetables support optimal thyroid function. They also are rich in prebiotics, which helps maintain a normal gut microbiome. They also make ideal snacks that can be incorporated with spice blends with dips.
In a review study, no clear association with any particular food and thyroid cancer was seen. However, a protective effect was seen for non-cruciferous vegetables (R).
BOTTOM LINE: non-cruciferous vegetables SHOULD be part of a hyperthyroidism diet plan as well as for patients with hypothyroidism.
By far the best source of selenium, Brazil nuts are protective for the thyroid (R, R). However, the content of selenium in brazil nuts, or any food for that matter, can be highly variable. Why? Soil content varies hugely (R).
Selenium deficiency in some regions can be severe due to regional soil selenium distribution. For example, animals grazing in selenium-poor soils can die due to selenium deficiency unless they are supplemented. In other areas of the world, selenium can reach toxic levels in the soil (R).
You can do your research in your area, but I highly suggest testing selenium levels for your thyroid patients. Supplementation may be a good way to improve low nutrient levels.
As with any type of food, it is wise to alternate Brazil nuts with other foods. For example, people following gluten-free diets often begin eating copious almond products. This, in turn, can create a new sensitivity.
Getting too many Brazil nuts can also result in selenium toxicity. Symptoms include garlic breath, nausea, diarrhea, skin rashes, irritability, brittle hair and nails, hair loss, discolored teeth, a metallic taste in the mouth, and nervous system problems. The recommended intake is just six nuts a day and not every day (R).
Also, see the section about healthy fats and the importance of soaking nuts. The goitrogen section describes why your nuts should also be cooked.
BOTTOM LINE: Brazil nuts are a simple food to add to your patients’ AIP food list.
Fresh, wild-caught fish including:
- Wild salmon
Fish is a great source of protein, selenium, zinc, and iodine, many trace nutrients that thyroid tissues require for optimal function.
Weight loss is a common symptom of hyperthyroid disorders, so providing adequate protein through fish may help prevent excessive weight gain (R). For hypothyroidism, protein supports the proper production of thyroid hormones as well (R).
Omega-3 fatty acids from fish reduce inflammation and support healthy digestive function. Fish oil also supports an increase in thyroid signaling (R). Eicosapentaenoic acid (EPA) from fish oil was able to reduce thyroid damage due to toxins in a rat study as well (R).
BOTTOM LINE: wild-caught fish can be a great snack for your autoimmune thyroid patients.
Leafy greens are a great source of magnesium and antioxidants (R).
Foods for thyroid patients should include romaine lettuce, leaf lettuce, and/or spinach, daily.
Consider adding kale and crucifers too! Read on to learn about goitrogens and when to be careful using them.
Bottom line: snacks don’t have to come out of a package. Leafy greens can be added to smoothies and kale can be made into kale chips for a great AIP food idea. Meal plans for hypothyroidism should always include these magnesium-rich foods.
A lot of confusion abounds related to cruciferous vegetables and thyroid function. While considered goitrogens, broccoli sprouts do not hinder thyroid function (R).
In a clinical study of broccoli sprouts, thyrotrophic hormone, thyroxine, and tri-iodothyronine were normal even though the sprouts contained high concentrations (220 mg/100 g) of glucosinolates (R).
Raw broccoli sprouts are some of the most potent cruciferous vegetables out there and they don’t cause thyroid problems. Why? No one really knows, but because they help clear out toxins, we believe they actually can HELP thyroid function (R). As always, they should be eaten in a nutrient-rich diet full of iodine, vitamin A, zinc, and selenium.
BOTTOM LINE: Sprouts are very high in nutrients that can help reduce inflammation. AIP food lists should contain sprouted vegetables.
Other Protein Foods
Protein is involved in making the structure of hormones. Vegan diets may be too low in protein to convert T4 to T3 long-term. (R).
Have your patients include grass-fed beef, wild game, organic chicken, eggs, sprouted seeds, freshwater fish and seafood.
Why? Rich in protein, vitamins, and minerals, these foods include zinc and selenium, as well as high-quality protein foods that are good for thyroid function (R, R). They also help maintain lean body mass for those suffering from hyperthyroidism symptoms (R, R).
Special note about eggs: while a great protein, some patients do have antibodies to eggs and elimination may be required.
BOTTOM LINE: hyperthyroidism diets should include plenty of high quality of protein daily.
Fruits are generally anti-inflammatory but should be used in the context of a balanced diet. Be mindful of glycemic response, as insulin resistance impairs thyroid function (R).
All fruits can be considered part of a healthy diet for thyroid, including:
- Citrus fruits
BOTTOM LINE: Fruits in moderation are a nutritious addition to your patients’ thyroid meal plan. They contain vitamins for hyperthyroidism and hypothyroidism, including vitamin C and vitamin A.
Filtered water and herbal teas including:
- Holy basil
- Lemon balm
- Citrus teas
- Calendula teas
Kefir Types for Thyroid Patients
- Water kefir made with honey. Here is a wonderful recipe called Honey Rhubarb Water Kefir Soda
- Coconut kefir
You can consider honey kefir that is made with water as well. If you have ruled out dairy sensitivity, you could also consider honey kefir made with milk.
Other teas for probiotic benefits (in moderation):
- Puerh tea
- Green tea
These probiotic teas do have traces of caffeine, so they should be avoided with sensitivity or hyperthyroidism (R).
Why Limit Caffeine for Thyroid Patients?
Caffeine-containing beverages don’t need to be avoided in all cases but should be avoided during levothyroxine dosing (R). This is challenging for many patients because they often love their morning coffee!
Have your patients wait 30-60 minutes after thyroid medication to have coffee.
Coffee and caffeinated beverages can also be concerning if a patient has adrenal issues or is sensitive to the effects of caffeine. Your patients may feel better avoiding caffeine if they have symptoms of anxiety, insomnia, urinary frequency or migraines.
If your patient has hyperthyroidism, they will likely feel better without caffeine.
Caffeine should be reduced gradually to minimize withdrawal symptoms.
BOTTOM LINE: Herbal infusions and fermented teas and water or coconut kefir are good beverage options for patients with thyroid disorders.
A lot of controversy surrounds fats, even when considering thyroid function. Context is everything. A balance of high-nutrient foods should include healthy fats to help with nutrient absorption and for the production of hormones.
However, some research suggests a moderate fat intake. A high-fat diet compared to the standard diet reduces thyroid function, T4 levels decreased and TSH increased, in a study of male rats (R).
The fat was both saturated and monounsaturated in this study. A diet high in lard also decreased thyroid function in an animal study (R).
Studies suggest that a high-fat, low-carbohydrate diet may be helpful for patients with Hashimoto’s thyroiditis. These are also good foods to eat with hyperthyroidism of all types. See more in the ketogenic diet section.
Recommended fats for thyroid:
- Virgin unrefined coconut oil
- Coconut milk
- Extra virgin olive oil
- Grass-fed Ghee
- Variety of Nuts
Nuts should be avoided for those patients who have nut sensitivities or nut antibodies. A good way to determine if a patient has sensitivities is through following a period of 3-4 weeks of elimination if you suspect a sensitivity.
Sprouting Seeds and Nuts
It is ideal to sprout seeds and nuts to reduce the anti-nutrient compounds in these foods. Sprouting times vary by type of seed or nuts. For more details about how to sprout nuts, visit EatBeautiful.Net.
Fermenting Seeds and Nuts
You can take it a step further and ferment these foods as well.
Fermented foods have been shown to be good for digestion due to the benefits of probiotics found in these products (R). These foods have also been found to contain higher nutrient and anti-oxidants levels compared with their regular food counterparts (R).
Certain foods have biological compounds that are not able to be digested by the body. These anti-nutrients can impair digestion and nutrient absorption (R).
The fermentation process releases enzymes these substances are catalysts that will break down these anti-nutrients and improve gastrointestinal function (R).
The weakened outer matrix in seeds and nuts will give way to more vitamins and minerals (R).
Here is a video about how to make fermented nuts and seeds.
Cooking Nuts after Soaking and Fermenting
Nuts can contain goitrogens when they are raw. It is advisable to cook nuts after a period of soaking and/or fermenting. See the goitrogen section below for more details.
Coconut Oil for Hypothyroidism
Coconut oil is rich in medium-chain triglycerides, which are metabolized quite differently than other types of fats. They absorb directly into the bloodstream instead of the lymphatic system.
Medium-chain triglycerides may help support weight loss, energy metabolism, and improve satiety from meals. For these reasons, patients with hypothyroidism may benefit from using coconut oil (R).
Ketogenic Diet for Hypothyroidism
Ketogenic diets are high in fat, moderate in protein and low in carbohydrate. Keep in mind, variety, and use of fats is all about context. Avoid frying or high temperature cooking to minimize toxin production.
Many people do successfully follow a ketogenic-style diet without thyroid compromise. In fact, a study of patients with Hashimoto’s thyroiditis patients found reduced thyroid antibodies by following a keto diet (R).
A low carbohydrate diet high in fat in healthy adults reduced T3 levels but not T4, but when a low carbohydrate diet given with high protein was provided, thyroid function did not change (R). This study was very short-term; only 1 week, and in healthy adults, so conclusions are challenging.
A ketogenic diet reduced thyroid function in people who were following this diet for epilepsy over a 6 month period (R).
Did these diet patterns reduce important thyroid nutrients? Possibly. It appears that a ketogenic diet may only be helpful for the thyroid if a patient already has an existing active autoimmune disease.
BOTTOM LINE: Fat can be an important part of a patient’s diet with thyroid disease and ketogenic diets may improve Hashimoto’s thyroiditis. A balance of high-quality vegetables and proteins with fats is important.
Fermented Foods for Thyroid Nutrition
- Kombucha, unsweetened
- Goat cheese, if the patient tolerates
- Apple cider vinegar
- Water kefir
- Coconut kefir
- Some honey kefirs
BOTTOM LINE: fermented foods should be included to help replace healthy microbes in the digestive tract for people with thyroid disease.
Other Foods and Herbs that Can Help Heal the Gut
Herbs may help restore the digestive lining called the mucin layer and/or reduce inflammation in the gut. This layer is a barrier that helps reduce the uptake of toxins but also helps protect the tight junctions of the epithelial lining. These herbs and foods can include the following (R, R, R, R, R, R, R, R, R, R):
- Marshmallow root
- Slippery elm
- Boswellia serrata
These herbs are safely used in doses available in teas or in foods. Supplements can be a helpful addition for thyroid patients as well to maximize healing.
Caution with dosing of licorice. Use less than 100 mg per day of glycyrrhizic acid to avoid negative side effects (R).
BOTTOM LINE: Plants as medicine and food can be helpful in healing the digestive tract for your patients.
An In-Depth Look at Goitrogens and Thyroid Health
Goitrogenic foods or substances are simply something that causes goiter. Goiter is an enlargement of the thyroid gland (R).
Goitrogens can cause goiter by interfering with iodine uptake in the thyroid gland. When you are low in iodine, the thyroid gland is unable to produce the hormones T4 and T3 (R).
The low T4 and T3 stimulate the body to make more TSH. The thyroid gland responds to TSH by making more hormones, thus causing growth or enlargement of the thyroid (R).
Before we delve into the details of goitrogens, remember to keep in mind that goitrogens tend to be healthy foods.
Large amounts of them can be a problem for people with thyroid disorders, but once the body heals, you can slowly increase them for your patients with thyroid disorders.
Keep in mind, also, your patients really need to eat a lot of these foods for them to be a problem in most cases.
Bottom Line: Eat iodine-rich foods and selenium-rich foods, along with protein to reduce the risk of goitrogenic effects.
Types of Goitrogenic Foods & Thyroid Function
Goitrogenic substances from cruciferous vegetables (glucosinolates) include:
During chewing and digestion, an enzyme called myrosinase breaks down glucosinolates into both goitrogenic and non-goitrogenic byproducts (R).
Cruciferous vegetables with goitrogenic potential include:
- Bok choy
- Brussels sprouts
- Chinese cabbage
- Collard greens
- Mustard greens
Eating typical serving sizes of raw broccoli, Chinese cabbage, bok choy, broccoli rabe) contain low enough goitrogen content that it won’t impair thyroid function, even if eaten daily, for most people.
In contrast, excessive intake (1 kilogram (kg) per day for months) of raw Russian/Siberian kale, some collards, and Brussels sprouts, all of which have high progoitrin concentrations, does decrease iodine uptake into the thyroid and reduces thyroid hormone production (R).
A kilogram of kale is a lot. However, in some cultures, this does happen.
Eating a 1/3rd pound of cooked Brussels sprouts EVERY DAY for a month did not change thyroid function (R).
Since 90% of thyroid problems occur for autoimmune reasons, it is more important to focus on healing the gut for most people than to worry about goitrogens; as long as you get enough iodine.
Cooking lowers the goitrogenic content of foods by up to 90 percent. Steaming cruciferous vegetables until fully cooked reduces goitrogens by 66 percent.
Boiling for 30 minutes destroys 90 percent of the goitrogens. This is because cooking stimulates the production of myrosinase, an enzyme that helps reduce the activity of glucosinolates in the body (34).
Bear in mind, cooking reduces a lot of valuable nutrients, so a balance of eating both cooked and raw vegetables is probably a smart plan for most patients (R).
BOTTOM LINE: Goitrogens are inactivated by cooking vegetables.
Flavonoids as Goitrogens
Flavonoids, in very high amounts, reduce thyroid function by decreasing thyroperoxidase activity which is needed for the production of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). (R, R, R). This can include beverages like:
- Red wine
- Green tea
Green tea in high amounts may reduce T3 and T4 while increasing TSH levels according to a study in rats (R).
Others foods that have goitrogens:
- Bamboo shoots
- Sweet potato
- Yuca (cassava or manioc)
- Tapioca (starch derived from yuca)
Millets and Thyroid
Millet in the diet contains C-glycosylflavones, which produce effects similar to small doses of the hyperthyroid thyroid drug, methimazole, which works by stopping the thyroid from producing too much thyroid hormone (R).
The maximum anti-thyroid effect is from the bran of millets, which contains the highest amount of C-glycosylflavones (R).
BOTTOM LINE: flavonoids can impair thyroid function if eaten in excess by patients. Autoimmune protocol diets should include cooked versions of these foods until the balance is restored in the body.
Soy and Thyroid
Soy and thyroid are not the best combinations. Soybeans have a goitrogenic effect, but only appears to occur if people are also low in iodine intake or who have an existing thyroid disorder (73).
In a meta-analysis study, supplemental soy and thyroid function were examined. Supplementing the diet with soy, as isoflavones or soy protein, increases TSH levels, but has no effect on T3 and T4 levels.
Soy and Hypothyroidism
However, for patients who had hypothyroidism at baseline, soy reduced thyroid function to a greater degree (R).
The mechanism that soy has on thyroid function is that isoflavones can reduce thyroperoxidase activity, ultimately affecting the adequate production of thyroid hormones (R).
BOTTOM LINE: Soy is a common food sensitivity. It should be avoided in the first phases of healing until the sensitivity is determined and iodine balance is restored.
Cyanogenic Glycosides as Goitrogens
- Bitter cassava root
- Bamboo shoots
- Lima beans
Luckily, when cooked, these compounds are 90-100% eliminated. For patients with thyroid disorders, the cooking of these foods should be recommended.
Cooking destroys the enzyme responsible for activation of progoitrin to goitrin thus negating its anti-thyroidal potency.
BOTTOM LINE: Have your patients cook foods that contain cyanogenic glycosides before eating them.
A common misconception is that the following foods have goitrogenic effects (79):
While the seeds do have cyanogenic glycosides, fortunately, the edible fruit part only contains trace amounts (R).
Iodine and Goitrogens
Goitrogenic foods need to be balanced with iodine-rich foods.
Iodine in the diet needs to be carefully considered. Many lifestyles, such as vegan diets, can be very low in iodine. Chemicals in the environment can also speed up the loss of iodine from the body.
Two billion people worldwide are iodine deficient (R).
The prevalence of iodine deficiency and iodine insufficiency is now thought to be quite high. Forty-four percent of women trying to conceive had an iodine deficiency (R).
Iodine intake is a problem in part because the intake of processed foods has dramatically increased. Packaged convenience foods do not contain iodized salt and may additionally cause damage to the thyroid-related to inflammation (R).
Additionally, chemicals and medications interfere with iodine in the body. Those include fluoride, chloride, bromide, and more.
The use of a high-quality water filter is prudent if your patients have tap water with chlorine.
Avoid fluoridated water and chlorinated water
Fluoridated water may increase your iodine needs and reduces the function of your thyroid as well (R).
BOTTOM LINE: Iodine is a critical nutrient for thyroid health. Levels should be monitored. If iodine is needed is should be increased slowly and through natural sources.
Patients who are susceptible to goitrogenic foods
Certain groups of patients need to take special considerations when it comes to goitrogenic foods (R):
- Pregnant women and breastfeeding women: increased iodine needs in an ever-increasingly iodine-poor environment.
- Almost half of women who breastfeed do not have adequate iodine in their breast milk for their infants
Gluten & other Food Sensitivities
A trial elimination of gluten and dairy should be for at least 3-4 weeks. Please refer to our gluten post for detailed information about gluten and thyroid issues.
Can Goitrogens HELP the thyroid?
In short, sometimes. Why? Foods like broccoli and glucosinolates like cruciferous vegetables are potent detoxifiers. They can be great foods to eat with hyperthyroidism for this reason. The toxic burden in the body is reduced by these foods, and thus, has a net anti-inflammatory effect for thyroid patients.
How to Add Goitrogens
Once the gut begins to heal and nutrients are restored, you can slowly increase the above goitrogens.
If you suspect a patient has thyroid issues, make sure you run a full thyroid blood work panel, which should include the standard TSH and T4, but also T3, free T3, free T4, and thyroid antibodies.
Worst Foods for Hashimoto’s and Other Autoimmune Thyroid Disorders
Hyperthyroidism foods to avoid are generally processed or foods that stimulate an imbalanced immune response. The following are examples of foods to eliminate to rule out sensitivities and to support the healing process for all types of autoimmune thyroid disorders.
Gluten has a negative impact on most, if not all cases of Hashimoto’s and possibly Grave’s disease as well.
Other foods that people should minimize or avoid with autoimmune thyroid disorders:
Omega-6 is an essential fatty acid but becomes inflammatory when it is out of balance with omega-3 in the diet (R). Most westernized cultures have too much inflammatory omega 6 fats in their diets (87).
These omega-6 rich oils include:
- Corn oil
- Soybean oil
- Other highly-processed oils, such as:
- sunflower oil
- safflower oil
- cottonseed oil
Omega-6 fats have increased exponentially since the use of vegetable oils were introduced into the human diet, especially soybean oil (R). Omega 6 fats increase the pro-inflammatory compounds called eicosanoids, including (R):
These, collectively, cause inflammation, pain, vasoconstriction, pro-aggregation, infiltration of immune cells, and release of reactive oxygen species (R).
BOTTOM LINE: Omega-6 fats are often hidden in many food products. To minimize these types of fat from the diet limit and avoid processed foods. Instead, include omega-3 fats from foods like fish, fish oils, and fats like extra virgin olive oil and coconut oil.
Sugar and Thyroid
Sugar increases surges in insulin in the body. This creates a negative feedback loop with the thyroid. Sugar also increases inflammation compounds in the body that can further worsen thyroid function (R, R).
Bottom line: While no direct evidence shows that sugar itself reduces thyroid function, insulin resistance certainly does.
Some beverages should be used minimally, including:
- Sports drinks
- Sweetened almond or rice milk
Coffee and Hypothyroidism
Coffee interferes with levothyroxine for hypothyroidism. It should be consumed 30 to 60 minutes after taking thyroid medication. A great overview of coffee and thyroid medication was created by The Thyroid Pharmacist.
Coffee May Change the Gut Microbiome
Coffee fed rats also exhibited insulin sensitivity as well as changes in their microbiome. They exhibited higher ratios of Firmicutes (F)-to-Bacteroidetes which are predominantly seen in obese individuals (R, R). The infectious Enterobacteria levels were also elevated in these animals (R).
Caffeine and the Thyroid
Caffeine has been shown to have largely positive effects when consumed in moderate doses of 3 to 4 cups a day (400 mg per day) by healthy populations (R).
Excessive consumption can lead to problems especially in those in with underlying medical conditions (R). Others may be sensitive to the effects of caffeine due to a metabolic or genetic issue (R, R).
Since having a thyroid condition is a medical issue, caution should be exercised when consuming coffee and other caffeine-containing beverages.
Caffeine May Affect Hormone Function
Research has illustrated how caffeine can affect hormone function. Daily consumption was shown to reduce insulin sensitivity in 16 healthy adults. A randomized, double-blind, placebo-controlled crossover trial found elevated insulin levels among those who consumed 400 mg of caffeine over a 7 day period when compared with the placebo (R).
Caffeine Products with Gluten May Harm the Thyroid
Some coffee and other caffeine-containing products have been found to have traces of gluten. Gluten consumption can alter thyroid function.
Caffeine May Disrupt Sleep Patterns
High doses of caffeine 500 to 600 mg have been shown to cause insomnia. Drinking coffee too close to bedtime can disrupt the body’s circadian rhythm and sleep quality (R). Research recommends that refraining from caffeine at least 6 hours before bedtime is important for a good night’s rest (R).
Caffeine May Impair Nutrient Absorption
Caffeine has been found to impair iron and zinc absorption which are critical nutrients needed for thyroid function (R).
The polyphenols in coffee can bind to nonheme iron and prevent intestinal absorption. Even combining nonheme iron with just 150 to 250 ml of coffee has been found to reduce iron absorption by 24 to 73 percent (R). Consumption of coffee should be avoided with nonheme iron intake.
Coffee contains phytates. These compounds have been known to increase zinc deficiency. Coffee also has been shown to reduce zinc bioavailability by 21 to 32 percent in vitro studies. More research needs to be done on coffee consumption and zinc status in humans (R).
Caffeine Consumption May Decrease Bone Mass
Caffeine can affect calcium levels and lead to decreased bone mass. Calcium is needed for vitamin D to help regulate thyroid function. Individuals who are not getting adequate calcium intake will be at risk if they consuming less than the daily recommended calcium intake (R).
Caffeine Consumption May Lead to Inflammation
Coffee may lead to an increase in inflammation. Moderate-to-high coffee consumption (greater than 200 mg per day) was linked to higher inflammatory markers including C-reactive protein (CRP), interleukin 6 (IL-6), serum amyloid-A (SAA), and tumor necrosis factor α (TNF-α) when compared with noncoffee drinkers. Men had a 50 percent higher IL-6, 30 percent higher CRP, 12 percent higher SAA, and 28 percent higher (TNF-α). Women’s blood levels showed a 54 percent higher IL-6, 38 percent higher CRP, 28 percent higher SAA, and 28 percent TNF-α. White blood cell counts were also higher in those who drank coffee 3 percent for men and 4 percent for women (R).
Inflammation can negatively affect the thyroid and cause further damage to this organ (R). Hormone levels should be periodically tested to see how coffee consumption may be affecting the thyroid.
Moderate doses (about 400 mg per day or 3.5 mg/kg of body weight) has been shown to increase blood pressure, cortisol, and norepinephrine levels in healthy males with habitual or light consumption of caffeine. Elevations were also seen at rest indicating caffeine can put the body in a stressed state (R).
Caffeine can also disrupt sleep. Regular caffeine consumption can lead to sleep disturbances and daytime sleepiness (R).
BOTTOM LINE: If your patient is suffering from nutrient deficiencies, gut dysfunction, insomnia, fatigue, and/or insulin resistance it may be a good idea to look at a reduction of the caffeine in their diet as a means for improved thyroid function.
Autoimmune Protocol (AIP) Diets for Thyroid
Functional nutrition assertions are that any lifestyle plan should be individualized based on a patient’s detailed history and symptoms. Many people try autoimmune protocol meal plans and get relief from their disorders, including Hashimoto’s and Grave’s disease (R).
Be aware of sensitivities to dairy, gluten, and eggs. Any sensitivity or food allergy may aggravate hyperthyroidism by increasing inflammation that begins in the gut.
As an example, a group of 180 patients with Hashimoto’s thyroiditis on a low-carbohydrate (no grains, sugar, or dairy, or fruit) and no goitrogenic foods (R).
The diet composition was:
- carbohydrates 12%–15%
- proteins 50%–60%
- lipids 25%–30%
These patients were instructed to eat large leafy and other types of vegetables and only lean parts of red and white meat, avoiding goitrogenic food.
The following items were also excluded from the diet: eggs, legumes, dairy products, bread, pasta, fruits, and rice. There was a mean decrease in body weight and a decrease in fat mass.
A significant drop in sentinel autoantibodies in Hashimoto’s thyroiditis also occurred.
AIP Gets to the Root of Leaky Gut
The root of all autoimmune likely originates in the gut, and thus, may benefit from healing leaky gut syndrome, replenishing nutrients, and restoring a healthy microbiome. Eliminating food triggers such as gluten is likely very helpful as well.
All autoimmune diseases fall on very discreet genes. However, having a specific gene for an autoimmune disease does not mean you will have one. Over 20 genes are linked specifically to autoimmune thyroid issues.
Loss of immune tolerance, or the health of our gut, plays a very big role in whether or not your patients will get thyroid disease or not. These genes are either accelerated or muted by various epigenetic factors. There is a large epigenetic factor in their diet.
6 weeks of an elimination diet followed by 5 weeks of a maintenance diet reduced inflammation as shown by endoscopic evaluation in 15 patients with ulcerative colitis and Crohn’s disease (R).
Wahls elimination diet protocol is effective in treating an autoimmune disease known as multiple sclerosis as shown by 3 small studies. Fatigue and quality of life all improved in these studies. Wahls’ elimination diet is considered an effective AIP diet plan (R).
Thyroiditis disorders, including Grave’s disease and Hashimoto’s disease, are likely to co-occur with multiple sclerosis and are thought to share the same causes by some experts (R).
BOTTOM LINE: The first section of this post includes foods that can safely be included on the AIP diet food list.
Lectins and Thyroid Issues
A low lectin diet may be helpful for some patients with autoimmune disorders (R).
Lectins come from legumes, grains, and nightshade vegetables and they include the following (R):
- Seed Spices
If joint pain is an issue, a higher level of suspicion for nightshade vegetables as a trigger may help. If a patient has tried other meal plans without success, a trial elimination of nightshades may be beneficial.
Testing Blood Thyroid Markers
Thyroid function tests can be useful to help guide the way as well for your clients as well as food sensitivity testing.
In some genetically susceptible individuals, high iodine in the diet might be a trigger for thyroiditis. This is thought to be transient (R).
Iodine-rich foods and supplements, as well as medicines such as amiodarone, and contrast dyes may increase immune thyroid reaction. This is because highly iodinated thyroglobulin is possibly more immunogenic than poorly iodinated thyroglobulin. However, conflicting results exist about this phenomenon, and more research needs to be done (R).
Perhaps this immune stimulation is more common in those that drastically change their iodine intake all at once. A slow, gradual increase in iodine may be beneficial depending on the person. The use of potassium iodide supplements should be avoided and intake from seaweed and kelp should be used with caution.
Seaweed and Kelp
Seaweed may be one food to take caution with or avoid altogether in some thyroid patients.
A modest amount of seaweed in your patients’ diets may help protect their thyroid. Why? Most of the population is deficient or insufficient in iodine and seaweed is the very highest of iodine-rich foods! It can contain over 700 micrograms per one-cup serving.
Iodine is known to control thyroid function. So having an iodine deficiency can lead to thyroid conditions including, thyroid nodules, goiter or enlarged thyroid gland, and hypothyroidism (R, R). Cancer thyroid has also been correlated with iodine deficiency in populations that have had long-standing dietary iodine deficiencies (R).
Iodine’s main effects are to decrease the response of the thyroid to thyrotropin (TSH); to acutely inhibit its own oxidation; to reduce its trapping after a delay; and, at high concentrations, to inhibit thyroid hormone secretion. Small changes in iodine intake are sufficient to reset the thyroid system at different serum TSH levels. This suggests that modulation of the thyroid response to TSH by iodide plays a major role in the negative feedback loop.
Seaweed at just 1 gram per day over two weeks was able to improve iodine levels in women with iodine sufficiency. This amount of seaweed contains 712 micrograms of iodine (R).
This translates to about 1/3rd of a seaweed snack pack per day.
Seaweed Precautions in Thyroid Conditions
On the other hand, it has been recommended for those with Hashimoto’s and other thyroid conditions to avoid seaweed and seaweed products.
According to Hashimoto’s expert Izabella Wentz, seaweed has the ability to stimulate an immune response due to the high iodine content. High iodine intake has been found to
- Cause new-onset autoimmune conditions
- Worsen the autoimmune attack in those with existing Hashimoto’s
- Could lead to additional thyroid cell destruction
A 2014 case study of a woman with no evidence of any pre-existing or underlying thyroid disease was found to develop hyperthyroidism followed by overt hypothyroidism after consuming 1800 μg of iodine for 10 days (R).
Iodine content in kelp varies depending on harvest location and preparation. Its average iodine content has been estimated to be about 1500 μg/g in dried varieties (R).
What occurred is iodine-induced thyrotoxicosis followed by a prolonged block of the sodium–iodide symporter activity as a consequence of excessive iodine consumption from kelp (R).
Those with pre-existing thyroid conditions should be careful with seaweed consumption and possibly avoid it depending on their iodine levels.
Excess iodine should also be avoided; a balance of iodine is critical for optimal thyroid function (15).
BOTTOM LINE: Seaweed consumption should be done with caution and possibly should be something to avoid depending on your client’s condition and levels of iodine.
Toxins in the environment can be damaging to the thyroid. Known toxins include polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol-A, and triclosan. They may have direct actions on thyroid hormone receptors (R).
Perchlorates from rocket fuels and nitrates reduce iodine uptake in the thyroid. Levels of urinary perchlorate were related to a decrease in total and free thyroxine levels in Southern California (R).
Sunscreens, such as benzophenone-2 may change thyroid function by altering thyroid-peroxidase activity (R). Octyl-methoxycinnamate also decreases T3 and T4 levels in an animal study (R). They should be considered thyrotoxic. Have your patients choose only mineral sunscreens without chemicals
Drugs and chemicals with goitrogenic effects
- Oxazolidines in paint
- Brominated vegetable oil
- Heavy metals
- Industrial byproducts
Awareness of your patient’s medications and exposures is critical to helping manage thyroid disease.
Other important tips for thyroid patients
- Manage stress – Stress reduces thyroid function because of excess cortisol and this creates this negative feedback to thyroid hormone production (R).
- Heal the digestive tract – Consider adding glutamine, an elimination diet, digestive enzymes, and plenty of fermented foods (R, R, R, R, R)
- Monitor vitamin D status – This deficiency is associated with numerous autoimmune diseases (R).
- Avoid bromide and other iodine toxins (R).
- Essential oils may help thyroid function by reducing inflammation in the body. These aromatic plant compounds can also help detoxify the body and replace harmful chemical use in the home and on the skin (R).
- Lack of sleep can decrease T4 and TSH levels, particularly in women (R). Natural sleep strategies include the use of lavender essential oil, magnesium supplements, and relaxing herbal teas (R, R, R).
- Hyperthyroidism diet and exercise should be moderate at first and gradually changed, especially if symptoms include rapid heart rate (R).
Thyroid function can be improved for your patients by encouraging them to avoid toxins, eat anti-inflammatory foods, avoid food sensitivities, and optimize vitamin and mineral intake. The best foods for hyperthyroidism, hyperthyroidism, and other thyroid disorders include spices, herbs, fish, fruits, protein, fermented foods, and herbal teas.
Focusing on healing the digestive tract and carefully balancing goitrogens with iodine will help your patients feel better.
The information on this website has not been evaluated by the Food & Drug Administration or any other medical body and is shared for educational purposes only. Consult your doctor or healthcare provider before making changes to your supplement regimen or lifestyle. Learn more in our disclaimer.
More Thyroid Nutrition Articles
- Functional Nutrition for Thyroid
- Alcohol and the Thyroid
- Should Your Clients go Gluten Free
- Mushroom Supplements for Thyroid Nutrition
- Infrared Sauna Benefits
- Mock Meat and the Thyroid
- What Are Optimal Thyroid Levels
- Signs of a Thyroid Condition
- Probiotics for Thyroid Health
- Thyroid and Eczema
This article was co-written by Heidi & Jeanette. The two met online in a dietitian Facebook group. Their love for researching nutrition and writing articles brought them together. Their past experiences with thyroid issues are what prompted them to start this website. You can learn more about Jeanette at her site https://jeanettekimszal.com/ and Heidi at her website https://www.thehealthyrd.com/