woman smiling at camera eating sushi

One of the best ways to support your thyroid function is to eat a healthy thyroid diet. Your food choices are especially important during stressful times or hormonal changes – when you are more vulnerable to thyroid problems.

To do its job and keep you symptom-free, the thyroid requires an adequate amount of specific vitamins and minerals. Iodine and selenium are the most important of these nutrients. But trace minerals, antioxidants and B vitamins are also critical for healthy thyroid function. While it’s possible to get too many of these nutrients, which can also cause problems, getting too few of them is more common.

lack of thyroid nutrients leads to symptoms

7 nutrients you need to improve thyroid function

1. Iodine

Your thyroid simply can’t function without iodine. If you’re deficient, your thyroid lacks a basic building block for producing its hormones – and your whole body is affected.

Top food sources for iodine:

  • Sea vegetables (kelp, dulse, hijiki, nori)
  • Seafood (clams, shrimp, haddock, oysters, salmon, sardines)
  • Iodized salt, preferably sea salt

In addition to the top food sources, there are good secondary sources: eggs, asparagus, lima beans, mushrooms, spinach, sesame seeds, summer squash, Swiss chard and garlic.

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2. Selenium

Selenium is essential to the thyroid because it’s used to convert T4 into T3, the most active form of thyroid hormone. Selenium and iodine are closely related, so a deficiency in selenium can lead to an iodine deficiency.

Top food sources for selenium:

  • Brazil nuts
  • Tuna
  • Organ meats
  • Mushrooms
  • Halibut
  • Beef
  • Soybeans
  • Sunflower seeds

3. Zinc

Since zinc is required for the conversion of T4 to T3, a deficiency can result in hypothyroidism. Not getting enough zinc, copper or iron causes an imbalance in the other two. So it’s important that you get enough of all 3 of these companion nutrients.

Top food sources for zinc:

  • Fresh oysters
  • Sardines
  • Beef
  • Lamb
  • Turkey
  • Soybeans
  • Split peas
  • Whole grains
  • Sunflower seeds
  • Pecans
  • Brazil nuts
  • Almonds
  • Walnuts
  • Ginger root
  • Maple syrup

4. Copper

Copper is also needed for the conversion of T4 to T3, so low levels can contribute to low thyroid function.

Top food sources for copper:

  • Beef
  • Oysters
  • Lobster
  • Shiitake mushrooms
  • Dark chocolate
  • Crabmeat
  • Tomato paste
  • Pearled barley
  • Nuts
  • Beans (soybeans, white beans, chickpeas)
  • Sunflower seeds

5. Iron

Research shows a link between iron-deficiency anemia and decreased thyroid function. Low iron can also prevent iodine from working effectively for the thyroid, while too much iron can also be a health problem. (It’s good to get levels checked if you’re not sure.)

Top food sources for iron:

  • Clams
  • Oysters
  • Organ meats
  • Soybeans
  • Pumpkin seeds
  • White beans
  • Blackstrap molasses
  • Lentils
  • Spinach

lentil soup

6. Antioxidants

Oxidative stress or inflammation from free radicals is associated with degenerative diseases, as well as the aging process.

Antioxidants such as vitamins A, C and E, along with iodine and selenium, are particularly important because they help your thyroid gland neutralize daily oxidative stress.

Top food sources for vitamins A, C and E:

Vitamin A
(beta-carotene form)
Vitamin C Vitamin E
  • Kale
  • Sweet potatoes
  • Carrots
  • Winter squash/pumpkin
  • Spinach
  • Cantaloupe
  • Broccoli
  • Asparagus
  • Liver
  • Lettuce
  • Guava
  • Peppers (chili, bell, sweet)
  • Kiwi
  • Citrus fruit
  • Strawberries
  • Broccoli
  • Cauliflower
  • Brussels sprouts
  • Papaya
  • Parsley
  • Greens (kale, turnip, collard, mustard)
  • Whole grains
  • Almonds
  • Soybeans
  • Beans
  • Sunflower seeds
  • Peanuts
  • Liver
  • Leafy green vegetables
  • Asparagus

7. B vitamins

Several B vitamins (B2, B3, and B6) are important for thyroid function because they are involved in manufacturing T4.

b vitamin rich foods

Top food sources for vitamins B2, B3 and B6:

Vitamin B2
Vitamin B3
Vitamin B6
  • Organ meats
  • Almonds
  • Wheat germ
  • Wild rice
  • Mushrooms
  • Egg yolks
  • Brewer’s yeast Vitamin B3
  • Rice bran
  • Wheat bran
  • Peanuts (with skin)
  • Liver
  • Poultry (white meat)
  • Brewer’s yeast Vitamin B6
  • Sunflower seeds
  • Wheat germ
  • Fish (tuna, salmon, trout)
  • Liver
  • Soybeans
  • Beans (lentils, lima, navy, garbanzos, pinto)
  • Walnuts
  • Brown rice
  • Bananas
  • Brewer’s yeast

What foods should you avoid for good thyroid function?

Certain foods contain goitrogens, which are compounds that make it more difficult for the thyroid gland to create its hormones. Soybeans, broccoli, cauliflower, cabbage and Brussels sprouts are a few examples. But there’s no need to cut these foods out of your diet completely. Instead, we recommend you cook these foods to reduce their goitrogenic properties instead of eating them raw. Another idea is to pair these foods with the thyroid-healthy foods listed above.

One food you may want to avoid is gluten: Many women tell us when they remove gluten-containing foods from their diet, they feel much better and notice fewer problems with their thyroid, especially autoimmune thyroid disease. Learn more about goitrogens, gluten and thyroid health.

Getting enough of the right nutrients

Getting as many thyroid-supporting nutrients as possible through food is ideal, but this isn’t always easy or even possible. If you tend to grab quick meals while standing at the kitchen counter, eat while driving or in front of a computer on a regular basis, consider supplementing with thyroid-supporting ingredients.

If you already have a diagnosed thyroid imbalance, talk to your practitioner about possibly using supplements before taking prescription hormones. The problem with prescriptions like Synthroid (levothyroxine, or T4) is that once you go on them, your thyroid backs down its efforts to produce hormones. This can make it difficult to get off of thyroid replacement drugs down the line. It’s also possible to use a supplement as “adjunct” therapy alongside prescription medications — many women report good results with this protocol.


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22 Pizzorno, L., & Ferril, W. 2005. Chapter 32. Clinical approaches to hormonal and neuroendocrine imbalances. Thyroid. In Textbook of Functional Medicine, ed. D. Jones & S. Quinn, 647. Gig Harbor, WA: Institute for Functional Medicine.

References for text box: What does active thyroid hormone do?

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c Weinstein, S., et al. 1994. Thyroid hormone increases basal and insulin-stimulated glucose transport in skeletal muscle. The role of GLUT4 glucose transporter expression. Diabetes, 43 (10), 1185–1189. URL (abstract): http://diabetes.diabetesjournals.org/cgi/content/abstract/43/10/1185 (accessed 05.12.2009).

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