10 Foods for Thyroid Health—And 3 To Avoid

If you have thyroid issues, the foods you eat can affect how you feel.

The proper functioning of your thyroid gland relies heavily on iodine, an essential trace element. The thyroid gland is responsible for producing thyroid hormones, which play a crucial role in regulating various bodily functions. According to the National Institutes of Health (NIH), without an adequate supply of iodine, your thyroid may struggle to produce enough thyroid hormone, potentially leading to thyroid disorders like hypothyroidism or even the development of a goiter—a condition in which the thyroid gland enlarges in an attempt to compensate for the shortage of thyroid hormones (Medline Plus).

While iodine deficiency isn’t a common concern for most Americans, thanks to the widespread iodization of table salt, certain dietary choices or restrictions can impact your iodine intake. For instance, individuals following low-sodium diets, often recommended for heart health, or those adhering to vegan diets may need to consider alternative sources of iodine to maintain optimal thyroid health.

Exploring Seaweed as an Iodine-Rich Option

One of the primary sources of iodine that often flies under the radar is seaweed. Various types of seaweed are rich in iodine, making them a valuable addition to your diet. However, it’s essential to exercise caution when incorporating seaweed into your meals due to the significant variation in iodine content among different seaweed species. Mira Ilic, a registered dietitian at the Cleveland Clinic, highlights this variability, noting that commercially available seaweeds can have iodine concentrations ranging from 16 mcg/g to a staggering 2,984 mcg/g (NIH).

While seaweed offers substantial iodine benefits, consuming excessive amounts can be counterproductive. Too much iodine can have adverse effects on your thyroid, potentially triggering or exacerbating hypothyroidism. To strike the right balance, health experts recommend consuming seaweed in moderation. Cynthia Sass, MPH, RD, Health’s contributing nutrition editor, suggests incorporating one fresh seaweed salad per week alongside your sushi consumption. Additionally, it’s advisable to avoid seaweed teas and supplements, which can lead to excessive iodine intake.

Iodine in Dairy Products

For those who don’t fancy kelp salads or seaweed-based dishes, dairy products provide a reliable source of iodine. On average, a cup of dairy products contains around 85 mcg of iodine, as reported by the NIH. However, the iodine content in dairy can vary due to several factors.

Livestock are often supplemented with iodine, and iodine-based cleaners are used during the milking process. These variables can impact the iodine levels in dairy products. For instance, samples of nonfat milk analyzed by the NIH showed iodine content ranging from 38 to 159 mcg per cup.

Opting for plain, low-fat yogurt or Greek yogurt can be an effective way to boost your iodine intake, with these dairy products contributing approximately 50% of your daily iodine needs, as per the NIH.

Selenium in Brazil Nuts

Brazil nuts offer more than just a unique flavor; they also contain selenium—a vital nutrient involved in regulating thyroid hormones. Selenium plays a protective role in preventing long-term thyroid damage in individuals with thyroid-related issues such as Hashimoto’s and Graves’ disease. A 2013 review in the journal Clinical Endocrinology underscored the potential benefits of selenium in thyroid health.

However, it’s important not to go overboard with Brazil nuts, as they are exceptionally rich in selenium. Just one kernel can contain between 68–91 micrograms of selenium, and the upper limit for daily selenium intake is set at 400 micrograms. Excessive selenium consumption can lead to undesirable side effects, including “garlic breath,” hair loss, discolored nails, and, in severe cases, heart failure, warns Ilic.

Milk as an Iodine-Rich Beverage

Milk and milk products stand out as one of the best dietary sources of iodine. Unfortunately, plant-based milk substitutes, such as soy and almond beverages, contain relatively small amounts of iodine. This discrepancy in iodine content highlights the importance of choosing traditional dairy options when aiming to boost your iodine intake.

As dairy consumption trends have declined over the years, with per capita fluid cow’s milk consumption decreasing consistently, the need to emphasize the role of milk in maintaining iodine intake becomes apparent. Drinking just one cup of low-fat milk can fulfill approximately one-third of your daily iodine requirements. Additionally, opting for milk fortified with vitamin D can offer further benefits, as research has shown a potential link between vitamin D deficiency and hypothyroidism.

Meats: Zinc for Thyroid Health

Zinc is another essential nutrient for thyroid health. Your body relies on zinc to produce thyroid hormones, and insufficient zinc intake can lead to hypothyroidism, according to a 2013 study published in the International Journal of Trichology. Interestingly, the relationship between zinc and thyroid hormones is reciprocal—thyroid hormones help absorb zinc. Consequently, a deficiency in zinc can have cascading effects, potentially causing severe issues such as alopecia (hair loss) (International Journal of Trichology).

While many people in the United States already meet their zinc needs through their diet, those with poor dietary habits or gastrointestinal disorders affecting zinc absorption may be at risk for a deficiency. Meats, such as beef and chicken, are excellent sources of zinc, providing varying amounts of this vital nutrient. A 3-ounce serving of beef chuck roast contains 7 milligrams of zinc, a beef patty offers 3 milligrams, and a 3-ounce serving of dark chicken meat contains 2.4 milligrams (NIH).

Fish: A Natural Source of Iodine

Fish, thanks to their environment, provide a natural source of iodine. Iodine is present in seawater and soil, which gets absorbed by aquatic life, including fish. As a result, fish offer a valuable dietary source of this essential trace element. Researchers have observed that individuals living in remote, landlocked regions without access to iodine-rich seafood are more susceptible to goiter development (BMC Public Health).

Different fish species contain varying amounts of iodine, with some offering particularly robust iodine content. For example, a 3-ounce serving of baked cod provides about 158 micrograms of iodine, enough to meet your daily iodine requirements if you are neither pregnant nor lactating, according to the NIH. Even fish sticks, a convenient option for many, deliver a healthy dose of iodine, offering 58 micrograms in a 3-ounce serving.

Shellfish: Iodine and Zinc in One Package

Shellfish, including lobster and shrimp, emerge as notable sources of iodine. A mere 3-ounce serving of shrimp—

equivalent to about four or five pieces—contains approximately 10% of your recommended daily iodine intake, according to the NIH. Moreover, shellfish are a two-for-one deal, as they are also good sources of zinc. Alaskan crab and lobster, for example, provide 6.5 and 3.4 milligrams of zinc in a three-ounce serving, respectively (NIH).

Eggs: A Balanced Source of Iodine and Selenium

Eggs offer a balanced nutritional profile, making them a thyroid superfood. One large egg contains roughly 16% of your daily iodine requirements and provides an additional 20% of your daily selenium needs, according to the NIH. Both iodine and selenium are vital for thyroid health, making eggs a valuable addition to your diet.

It’s worth noting that, unless otherwise advised by your healthcare provider, consuming the entire egg is recommended. Much of the iodine and selenium content is concentrated in the yolk, offering a comprehensive nutrient package.

Berries: Antioxidant Support for Thyroid Health

Maintaining thyroid health involves more than just iodine, selenium, and vitamin D. Antioxidants, which combat cell damage, are also crucial for thyroid function. According to a 2022 study in Biomedicine & Pharmacotherapy, antioxidants play a role in managing thyroid dysfunction, making foods rich in antioxidants beneficial for thyroid health.

Berries, across their various varieties, are excellent sources of antioxidants, as highlighted by Johns Hopkins Medicine. Among these options, black raspberries stand out as exceptional due to their high antioxidant levels. Additionally, black raspberries offer fiber and relatively low natural sugar content, making them a healthy choice for supporting thyroid health.

Cruciferous Vegetables: The Fine Balance

Cruciferous vegetables like broccoli, cauliflower, kale, and Brussels sprouts are a point of contention when it comes to thyroid health. These vegetables contain compounds called glucosinolates, which, in high amounts, may interfere with the body’s thyroid hormone production. However, it’s important to clarify that consuming typical serving sizes of these vegetables is unlikely to harm your thyroid function.

A 2016 study in Nutritional Reviews emphasized that the impact of cruciferous vegetables on thyroid function depends on both the amount and type consumed. Standard servings of raw broccoli, Chinese cabbage, bok choy, and broccoli rabe are generally considered safe for thyroid health. Excessive consumption, such as consuming more than 1 kg per day for several months of certain varieties like raw Russian/Siberian kale, collards, and Brussels sprouts, can potentially affect iodine uptake in the thyroid and thyroid hormone production.

In summary, cruciferous vegetables like cauliflower and kale are essential components of a healthy diet and can support thyroid health when consumed in moderate quantities. Additionally, cooking these vegetables can neutralize enzymes related to glucosinolates, further mitigating any potential concerns.

Soy: An Inconsistent Impact on Thyroid Health

The relationship between soy and thyroid health has yielded inconsistent findings. While there have been concerns that soy might negatively affect thyroid function and alter thyroid hormone levels, a 2019 meta-analysis published in Nature concluded that soy supplementation did not significantly impact thyroid hormones. The impact of soy on thyroid health appears to be minimal for individuals consuming average amounts.

For those with no underlying thyroid issues, there is generally no need to be overly concerned about the effects of soy on thyroid function. However, it’s important to maintain a balanced diet and monitor thyroid health when relevant, as individual responses to dietary components can vary.

Gluten and Thyroid Health

The connection between gluten and thyroid health primarily pertains to individuals with celiac disease or gluten intolerance. Research, as outlined in a 2021 review in Nutrients, has revealed a frequent coexistence of celiac disease and autoimmune thyroid diseases, such as Hashimoto’s thyroiditis and Graves’ disease. This association highlights the complex interplay between gut health, the immune system, micronutrient absorption, and thyroid function.

While it’s not entirely clear whether a gluten-free diet alone can effectively treat thyroid disease, individuals diagnosed with celiac disease must adhere to a strict gluten-free diet to manage their condition effectively. This dietary choice is essential for preventing symptom exacerbation and maintaining overall well-being.

Processed Foods and Iodine Intake

If you’re considering increasing your iodine intake through processed foods, think twice. Manufacturers are not required to use iodized salt in their products, creating a potential pitfall. The NIH notes that processed food manufacturers “almost never” employ iodized salt in their production.

As a result, increasing your consumption of salty, processed foods in an attempt to boost iodine intake can lead to an imbalance. This approach may introduce excessive sodium into your diet, which can elevate blood pressure and contribute to the development of heart disease, all while falling short in providing the necessary iodine.

Fast Food and Iodine Content

Fast food establishments also do not have consistent iodine practices. The American Thyroid Association (ATA) advises against consuming restaurant foods, as it is challenging to determine which restaurants use iodized salt.

The iodine content in common foods, as analyzed by the United States Department of Agriculture (USDA), demonstrates variations between fast food and non-fast-food options. For example, one fast food hamburger patty contained 3.3 mcg of iodine per 100 grams, while a non-fast-food ground beef patty contained 8 mcg of iodine per 100 grams.

Dietary supplements represent another consideration. These supplements are subject to minimal regulation by the Food and Drug Administration (FDA) and may vary widely in terms of their suitability for individuals. The effects of supplements can differ from person to person, influenced by factors such as type, dosage, frequency of use, and interactions with existing medications. Therefore, it is strongly recommended to consult with your healthcare provider or pharmacist before initiating any supplement regimen.

In conclusion, maintaining optimal thyroid health involves thoughtful dietary choices that balance iodine, selenium, and other essential nutrients. Incorporating a variety of iodine-rich foods like seaweed, dairy products, Brazil nuts, fish, shellfish, eggs, and berries, along with maintaining a well-rounded diet that includes antioxidants, can contribute to overall thyroid well-being. While cruciferous vegetables, soy, and gluten may raise concerns, moderate consumption is generally safe for most individuals. Avoiding excessive intake of processed foods and fast food, which may lack iodized salt, is advisable. Always seek personalized guidance from healthcare professionals when considering dietary changes or supplements for thyroid health. Thyroid health is a complex interplay of nutrition, genetics, and individual health factors, and tailored approaches offer the best path to well-being.