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  • Writer's pictureLiz Riesen, RD

Natural Thyroid Support

Updated: May 17, 2021

What does the thyroid do in the body?

Your thyroid plays a role in a wide variety of functions in the body including your metabolism, body temperature, heart rate, fertility, and even digestion.

If your thyroid is not functioning correctly you can experience fatigue, constipation, hair loss, frustrating weight gain, anxiety, and trouble sleeping.

Since these symptoms are also tied to many other conditions, the best way to determine if your thyroid is functioning correctly is through lab testing. To get accurate information, you need to test more than just your TSH level.

Did you know your TSH level is not actually produced by the thyroid? So why is it the first thing we test for when checking for an abnormal thyroid?

TSH is produced by the pituitary gland in the brain and its role is to stimulate the thyroid to produce thyroid hormones T4 and T3. I always recommend a full thyroid panel to make sure we have an accurate look at how the thyroid is functioning.

Comprehensive Thyroid Testing

A full thyroid panel includes pituitary (brain) hormone TSH as well as the thyroid hormones - T3, T4, reverse T3, and thyroid antibodies. We can look at the communication between the brain and thyroid when a full thyroid panel is done.

You can ask your doctor to order a full thyroid panel and go through insurance, or you can order your own thyroid panel with Ulta Labs, a popular nationwide laboratory. Ulta Labs has their Thyroid Panel - Basic Plus for $79. Find the thyroid panel and order it here.

It is important to have support and the right health care team behind you! Find a health professional who can help you understand the process and guide you through a supportive and natural healing process that you feel comfortable with.

In this article we will cover what foods and nutrients are best for supporting thyroid health. This article benefits women who want to prevent thyroid disease, women who have thyroid disease, and women who no longer have a functioning thyroid.

What if you don't have a functioning thyroid anymore?

If you no longer have a functioning thyroid, then you are actively taking thyroid medication and your body still needs to convert T4 into T3 active thyroid hormone, so these nutrients are important for all.

Nutrients for Thyroid Function

What food and nutrients that are important for thyroid health?

Each of these nutrients listed below play an important role in the function of your thyroid, however you need to make sure you are replenishing all nutrients in order to prevent imbalances and deficiencies. For example, supplementing with iodine if you have low selenium can actually make thyroid disease worse.


Selenium is an important nutrient because it is needed for the enzyme that converts T4 hormone into the active T3 hormone. If your body is deficient in selenium then hypothyroidism can develop due to low levels of thyroid hormone available.

Selenium is found in liver, seafood, and red meats. Selenium can also be found in Brazil nuts, but the amount present depends on the soil content. Unfortunately the range of selenium in 1 ounce of Brazil nuts can range from 55 mcg to 550 mcg.

Here is the supplement I recommend in my practice: Ecological Formulas Kelp


Iodine is essential for thyroid hormone production because the thyroid gland actually uses iodine with the amino acid tyrosine to create thyroid hormone. We only need about 150 micrograms (mcg) of iodine per day for optimal thyroid function.

3 oz. of cod has 99 mcg iodine 3 oz. shrimp has 35 mcg iodine

In the past, iodine deficiency was such an epidemic that the government ruled table salt needed to be fortified with iodine. This is why we have “iodized salt” as your general table salt.

It is important to know that too much iodine can stop thyroid synthesis, which is why many women with thyroid disease should avoid using iodized salt and other fortified foods to prevent excess iodine levels.

Avoiding fortified foods and choosing a high quality supplement with iodine and selenium will help to keep your nutrient levels balanced.

Here is the supplement I recommend in my practice: Ecological Formulas Kelp

Vitamin D

We call this a vitamin, but vitamin D functions more as a hormone in our bodies. This is why vitamin D deficiencies are significant and associated with autoimmune conditions, including Hashimoto’s (thyroid autoimmune disease).

The best way to get vitamin D is through our skin’s own production. However, it depends on where we live in the world, if we are able to get enough UV light from the sun to produce sufficient levels of vitamin D in our body. Here in the Midwest it is not likely we can make enough vitamin D outside of a couple of summer months.

Also, if you are like me and fair-skin then being in direct sunlight with no sunscreen for the 30 minutes necessary to produce enough daily vitamin D, is not a great idea (or pretty for that matter). If you have darker skin you need to be in direct sunlight with no sunscreen for a longer period of time, potentially 2 hours per day to make enough vitamin D.

This is why vitamin D supplementation is recommended for most adults. Vitamin D is fat-soluble meaning you should take this supplement with a fat-containing meal, ideally later in the day for optimal absorption. Most adults benefit from taking 2000 IU vitamin D3 daily. I also recommend that you find a supplement that includes vitamin K2, because it works with vitamin D and calcium to be absorbed into bones and maintain bone health.

Here is the Vitamin D supplement I recommend in my practice and use myself: Ortho Molecular Liquid Vitamin D with K2 or if you prefer capsule form, Designs for Health Vitamin D Synergy.

The Best Foods for Thyroid Health

Omega 3 Fatty Acids

There are a few different types of essential fatty acids that our body needs. Because of our diet and high prevalence of chronic inflammation, our balance of omega-3 fatty acids is depleted. Fatty acids are necessary for all of our cell membranes, energy production, and brain health.Omega-3 fats are specifically involved in the anti-inflammatory pathways in the body.

If we have inflammation present in our bodies (which we all do) and not enough omega-3 fatty acids, our thyroid function can actually decrease because it is needed for thyroid receptors (converts T4 to T3).

The best sources of omega-3 is cold water fatty fish like salmon, sardines, herring, and oysters. Some plants also have omega-3 sources, but the plant form still needs to be converted into omega 3’s EPA and DHA form, which the body does not do well.

When choosing an omega-3 supplement, make sure to find one that is third party tested and free of heavy metals, pesticides, solvents, PCBs, and other contaminants.

Here is the Omega-3 Fish Oil supplement I recommend in my practice and use myself: Nordic Naturals Liquid Omega 3 Lemon, or if you prefer capsule form Metagenics Omegagenics.


Magnesium is a powerful mineral that participates in over 300 enzymatic reactions in the body. It is estimated that up to 75% of the US adult population is low in magnesium (1)

You can find magnesium in green vegetables, especially dark leafy greens, because it is a component of chlorophyll (remember middle school science).

  • ½ cup serving of cooked spinach is about 78 mg of magnesium.

  • 1 cup of brown rice has 86 mg of magnesium.

  • 1 ounce of almonds has 77 mg of magnesium.

A fun fact I learned playing around in the kitchen is that sunflower seeds are also high in chlorophyll and therefore magnesium. If you bake cookies or muffins with sunflower butter, they will turn a bright green color as they cool! This is the chlorophyll in the seeds.

The unfortunate fact with magnesium is that we are seeing an increase in this mineral depletion in our bodies because our plants need to get their magnesium from the soil, and soil quality in the United States has continued to deplete over time. Therefore our magnesium intake has suffered.

There are many types of magnesium if you are looking for a supplement. Magnesium glycinate is easy to absorb and digest. If you have issues with constipation you can try magnesium citrate, another good form that can have a slight laxative effect.

Here is the magnesium supplement that I recommend in my practice, and also take myself: Natural Vitality CALM Lemon powder, or if you prefer capsule form Pure Encapsulations Magnesium.


Zinc is another nutrient involved in the synthesis of thyroid hormone and also one of the co-factors needed for conversion of thyroid hormone T4 into active T3. Zinc is also a big player in immune health as well as hormone production.

The World Health Organization (WHO) estimates that about 31% of the world’s population is deficient in zinc (4). So, why would that be?

Zinc is found in shellfish and red meats like beef. The form of zinc present in whole grains, legumes, and nuts is difficult for the body to absorb because it binds with phytates (also present in these foods). So they are not a reliable source of zinc.

If you notice a trend here, if you don’t eat much seafood and limit your red meat then you could be lacking many of the essential nutrients for thyroid function.

Here is the zinc supplement that I recommend in my practice: Megafood Zinc


Iron plays a role in supporting thyroid function and maintaining a balance of T4 and T3 hormones. If you have low iron levels, it can be difficult to heal hypothyroid disease and maintain stable thyroid levels. Iron is also an important player in immune health, like zinc and vitamin D.

The World Health Organization (WHO) predicts that about 25% of the world’s population is deficient in iron (5). That’s a lot of people!

Iron is found as two forms in food, heme- and non-heme iron. Heme iron has the best absorption and is present in animal products (liver, beef, chicken, eggs). Non-heme iron is found in plant sources, but it can be easily blocked by other nutrients like phytates.

Vitamin C can increase absorption of non-heme iron, so if you are trying to increase your iron levels make sure to include an iron source and vitamin C source at every meal. For example, make a smoothie that has a large handful of spinach (high in iron) + 1 cup strawberries (high in vitamin C).

Iron supplements can cause stomach irritation if they are synthetic form and taken on an empty stomach. Here is a whole food iron supplement I recommend in my practice that has been well liked. Gaia Herbs PlantForce Liquid Iron

It can feel like our body is working against us, but please know that is never the case!

If you're looking for additional guidance and support, let me know. Now is the time to invest in yourself and your body. You deserve to feel happy, energized, and comfortable in your body! Apply to work with me here

For tips, live videos, and to keep learning about nutrition and hormones, join my free online community!

Liz Riesen, Registered Dietitian

works specifically with women's hormones, inflammation, and digestive health. Often these conditions coexist and share common disruptive symptoms including bloating, weight gain, anxiety, mood swings, irregular cycles, and other inflammatory symptoms.

Liz is trained in identifying and healing food sensitivities, as well as balancing hormones naturally through nutrition and lifestyle. Follow me @moms.hormone.dietitian


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