June 22, 2020

Thyroid Vitamins: Which Foods and Supplements Help and Which to Avoid

It is estimated that 20 million Americans are currently living with some form of thyroid disease, and 60 percent do not know that they are affected (1). While thyroid disorders affect both men and women, women are five to eight times more likely to develop thyroid issues than men, and one out of every eight women will develop a thyroid disorder during her lifetime. Common types of thyroid disorders include:

  • Hypothyroidism, a condition in which the thyroid gland does not produce enough thyroid hormone
  • Hyperthyroidism, a condition in which the thyroid gland produces too much thyroid hormone
  • Thyroiditis, or inflammation of the thyroid
  • Nodules, goiter, and thyroid cancer

Thyroid vitamins are commonly marketed to patients who suffer from thyroid conditions, but it helps to understand which foods and supplements help and which to avoid when you have a thyroid disorder. 


Helpful Foods and Supplements


Thyroid disorders have been shown to correlate to deficiencies of several important vitamins and minerals. While it is unknown whether these deficiencies cause the disorders or make them worse, numerous studies have shown that getting proper nutrition in the form of the essential multivitamins, minerals, and dietary supplements listed below can help to improve thyroid disorder symptoms. As always, it’s best to speak to your doctor about your medical history before beginning any new supplement regimen.


Ashwagandha is an adaptogen that has been used to treat various medical conditions around the world for over 4,000 years. While many people think of ashwagandha as helping to reduce the body’s cortisol and stress levels, the supplement also has major benefits for those suffering from thyroid conditions. One study found that ashwagandha, a traditional medicine in Ayurveda, helped to normalize thyroid indices in patients with hypothyroidism by improving the levels of certain hormones that the thyroid gland needs to maintain normal function and health (2).   

On the contrary, ashwagandha for thyroid health can be a bit polarizing as it can worsen the symptoms of hyperthyroidism. This is why speaking to a medical professional for specific treatments is essential. 

Vitamin B12

We often think of vitamin B12 as an energy booster and an important supplement for brain health, but B12 also influences the health and function of the thyroid gland.  A 2008 study showed that vitamin B12 deficiency is common in patients with primary hypothyroidism (3). Therefore, people with low levels of vitamin B12 are considered to be at increased risk for hypothyroidism. Unfortunately, B12 is commonly found in animal products like fish, meat, eggs, and milk products, which means that many vegans and some vegetarians suffer from vitamin B12 deficiency.  

Vitamin D

It’s estimated that 40 percent of Americans suffer from a vitamin D deficiency, which can cause a number of health issues, including diminished bone density, autoimmune conditions, and diminished thyroid function. A 2013 study found that hypothyroidism is linked to vitamin D deficiency, and it appears that the two conditions are strongly correlated (4). Vitamin D is commonly found in fortified dairy products, fish, and animal products, as well as cereal and egg yolks. We can also receive vitamin D by spending time outside in the sun for 15 minutes each day.


More than 1.62 billion cases of anemia occur around the world each year, and the primary cause is iron deficiency, which disproportionately affects pregnant women, young children, and women with heavy menstrual bleeding. Iron is also needed to support thyroid health, and insufficient levels can lead to thyroid problems. Iron is responsible for helping convert the inactive T4 hormone into the active T3 hormone (5). Thyroid patients who do not have enough iron may experience increased fatigue and hair loss. Although iron is mainly found in meat, fish, and poultry sources, GEM sources its iron from curry leaves, making it an entirely plant-based source.

Thiamine (Vitamin B1)

Thiamine, or vitamin B1, is best known as an energy boosting vitamin because it is responsible for metabolizing carbohydrates into energy. Low levels of vitamin B1 can leave people feeling sluggish and fatigued, and some people may experience difficulty concentrating. Thiamine deficiency is commonly linked to an increased risk of autoimmune disorders, including thyroid function. A 2013 study found that patients with thiamine deficiencies who suffer from thyroid conditions could partially or completely eliminate their symptoms of fatigue by supplementing their diets with 600 mg of thiamine per day (6)

Helpful Foods


In addition to the foods listed above, there are many other foods that support thyroid health and function. One common concern is receiving too much of an individual vitamin or nutrient, which can adversely affect thyroid conditions and make symptoms worse. This is primarily an issue for patients who receive their nutrients from vitamin supplements rather than from real food. For example, receiving too much iodine can be harmful to patients with thyroid issues, but this is difficult to do through diet alone. Patients with thyroid disorders may benefit from consuming the following foods in support of thyroid health: egg yolks, fish and seafood, seaweed, algae, dairy products, and leafy greens (5)


Foods and Supplements to Avoid



Iodine is one of the most critical components of a healthy thyroid. The thyroid gland uses iodine from our diets to produce thyroid hormone, so it might seem strange to avoid supplementing your diet with iodine if you have a thyroid issue (7). If we don’t receive enough iodine through our daily diets, thyroid problems can develop. However, while iodine deficiency is the leading cause of thyroid disease in the world, that’s not the case in the United States, where much of our food and our salt is fortified with iodine. Although some Americans do suffer from an iodine deficiency, putting them at a higher risk of thyroid problems, the majority do not. Iodine should only be taken as a supplement if you have a confirmed iodine deficiency, which can be determined through a urinary iodine clearance test at your doctor’s office. People with thyroid problems who supplement with iodine but do not have an iodine deficiency can actually make their condition worse or trigger new symptoms and conditions, including nodules, hyperthyroidism, goiter, hypothyroidism, and Hashimoto’s thyroiditis (8).


While soy isn’t problematic for every type of thyroid condition, people with forms of hypothyroidism should be sure to avoid soy. Soy has been shown to hinder the absorption of certain hormones that hypothyroidism patients take to correct their hormonal imbalances, and the effects can occur even with minimal consumption (9). For example, drinking a glass of soy milk within an hour of taking your thyroid hormone can affect absorption, as can consuming soy in other foods. Soy is a staple of many traditional Asian diets and a popular component of many vegetarian and vegan products.

Cabbage and cruciferous vegetables

Your mom may have always told you to eat your vegetables, but it’s important to be careful about eating too much cabbage or other cruciferous vegetables like broccoli and cauliflower if you have thyroid issues. When eaten raw in large quantities, cabbage and other cruciferous vegetables have been shown to contribute to hypothyroidism, particularly in people with iodine deficiency or borderline iodine levels (10). Scientists believe that this is the result of metabolites generated by cruciferous vegetables that compete with the uptake of iodine by the thyroid. 

Highly processed foods

Most people recognize the importance of eating a healthy, well balanced diet that is rich in whole foods like fruits, vegetables, whole grains, and lean meats, but most of us still eat more processed foods than we would care to admit. Highly processed foods like hot dogs, cakes, cookies, and other treats are often high in calories, and patients with thyroid issues like hypothyroidism may struggle to maintain a healthy weight. Having an underactive thyroid can also increase your risk for high blood pressure, and highly processed foods tend to be packed with sodium, which can further increase the risk. It’s best to stick to whole foods as often as possible and save the processed stuff for an occasional treat.


By the Numbers: 


12: Percent of the U.S. population that will develop a thyroid condition during their lifetime

52,890: Number of new cases of thyroid cancer estimated in 2020 (12,720 in men and 40,170 in women) according to the American Cancer Society (11). 

10: Level of Thyroid Stimulating Hormone (TSH) above which a patient is diagnosed with hypothyroidism


Myth Buster:


  • Turnips and root vegetables are often thought to cause thyroid problems, but the opposite is true. Turnips and root vegetables, with the exception of cassava, are important dietary elements that are a healthy part of your diet regardless of thyroid issues (12)
  • Although iodine deficiencies are the number one cause of thyroid issues worldwide, this is not the case in the United States because iodine is added to many foods in the standard American diet. People with thyroid issues should avoid taking iodine supplements. 



1. https://www.thyroid.org/media-main/press-room/

2. https://www.liebertpub.com/doi/full/10.1089/acm.2017.0183

3. https://pubmed.ncbi.nlm.nih.gov/18655403/

4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921055/

5. https://www.healthline.com/health/thyroid-vitamins

6. https://pubmed.ncbi.nlm.nih.gov/24351023/

7. https://www.healthcentral.com/slideshow/fitness-and-exercise-tips-for-thyroid-patients

8. https://pubmed.ncbi.nlm.nih.gov/28290237/

9. https://pubmed.ncbi.nlm.nih.gov/16571087/

10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3496161/

11. https://www.cancer.org/cancer/thyroid-cancer/about/key-statistics.html

12. https://health.clevelandclinic.org/thyroid-issues-what-you-need-to-know-about-diet-and-supplements/

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