Nutrition for Your Thyroid

This post is part three in a series about women and hypothyroidism. Start at the beginning or read the last post. Here we dig into all the nutrients you need to make and convert thyroid hormones. In functional medicine we order labs for nutrient deficiencies, going with the “test don’t guess” approach. We go over food sources of these nutrients. We supplement as needed. In many cases, we clear up hypothyroid conditions simply by adding missing nutrients.

Iodine is first

You cannot make thyroid hormones without iodine. Women with Hashimoto’s autoimmune hypothyroidism also need iodine, but to be on the conservative side, we make sure your intake is not too high.

Iodine deficiency is a real thing

38% of the world’s population does not get enough iodine.

We often think that iodine deficiency is a thing of the past. It is not. Over one-third of the world’s population is iodine deficient. Here in the U.S. we stopped having a problem with iodine deficiency when we began adding iodine to salt in 1924.

We are now seeing a resurgence of iodine deficient hypothyroidism here. Why?

  1. We use less salt because high blood pressure is so common. Many follow low-salt or no-salt diets.
  2. If you try to eat a healthy diet, you may use sea salt, which is not iodized.
  3. Iodized salt is not used as much in general, and is no longer generally added to processed foods.
  4. More iodine is removed in the dairy industry (from feed supplements and sanitizing agents).

Iodine recommended intake and sources

If you aren’t eating iodine-rich foods, it’s likely you aren’t getting enough iodine. The World Health Organization recommends that women get 150 micrograms (mcg) of iodine per day. In food, this would roughly be:

  • 1 teaspoon of sea vegetables (dulse, nori, kelp, wakame, hijiki, arame)
  • 5 ounces of ocean white fish like haddock, sea bass, and cod
  • 2 cups yogurt or 3 glasses of milk (largely because of iodine use in the cattle industry)
  • 15 ounces of shrimp
  • 10 oysters
  • 2 ounces of cranberries
  • 6 large eggs, or 10 small eggs
  • 10 cups of strawberries
  • 2.5 potatoes (iodine is in the skins)
  • 2/3 teaspoon of iodized salt

The highest sources of iodine in food comes from sea vegetables, ocean white fish, and milk products. Iodine in plant foods is hard to determine because it depends on the iodine content of the soil. Keep in mind that 150 mcg is the lowest amount that’s needed to prevent acute deficiency. Your body may thrive with a higher intake.

  • Pregnant women need at least 220 mcg
  • Breast-feeding women need 290 mcg
  • If you don’t have Hashimoto’s, I recommend up to 800 mcg of iodine per day
  • With Hashimoto’s, stick with 150-200 mcg

Iodine is also very beneficial for breast health, mental performance, and the prevention of thyroid cancer. Do not go over 1.100 mcg supplemental iodine.

What are iodine deficiency symptoms?

  1. Hypothyroidism (remember your thyroid cannot make hormones without iodine)
  2. Goiter
  3. Impaired mental function
  4. For babies in utero: growth retardation, neurological deficits, miscarriage, and stillbirth
  5. Neurological deficits including ADHD and lower intelligence
  6. Increased risk of thyroid cancer
  7. For women, fibrocystic breasts (lumpy painful breasts)

200 micrograms of selenium

Selenium is the second most important nutrient for thyroid function. It is absolutely necessary for your thyroid to convert T4 to the active T3 hormone that is used by all the cells in your body. The optimal amount of selenium is 200 mcg. This is roughly the amount in four Brazil nuts.

Selenium also protects your thyroid gland. It’s actually dangerous to consume iodine without selenium. This can lead to destruction of cells in the thyroid gland. 


Iron deficiency is quite common for menstruating women, especially those who don’t eat red meat or liver. Why is iron so important? Your thyroid needs iron to make thyroid hormones, and it also needs it to convert T4 into the active T3.

It’s a catch-22 because many women who are hypothyroid don’t absorb iron well. So hypothyroidism can cause iron deficiency, and iron deficiency can cause hypothyroidism!

You don’t want to take a bunch of iron without knowing your levels. Too much iron is actually inflammatory. You want the right amount of stored iron, called ferritin. You also need the right amount of iron in your blood. That’s why it’s important to test instead of guessing.

Iron deficiency causes similar symptoms as low thyroid. This may cause your doctor to increase your thyroid hormone prescription unnecessarily.

If you do need more iron, you can get it from food or supplements. Your body absorbs heme iron from animal foods much better than nonheme from plants. Hands down, the most iron rich foods are liver (beef and chicken), oysters and clams. Without these foods you may need to supplement. Vitamin C helps tremendously with iron absorption.


Most women are deficient in magnesium today simply because it’s low in our soil. I recommend that all women take a minimum of 400 mg of a good quality magnesium supplement. This is one mineral that you probably will not be able to get from foods. Magnesium is needed to produce thyroid hormone, to convert T4 into T3, and also protects your thyroid from goiter along with iodine.

I only recommend magnesium chelate by Albion Labs. High quality supplements contain this type. It may be labeled Albion or TRAACS®. I prefer glycinate to citrate, as citrate has laxative properties. Read more about assessing your magnesium needs here.

Zinc balanced with copper

Zinc helps T4 convert to T3. In this study when T4 was normal, T3 low, and rT3 high, zinc helped normalize these markers. Therefore, it helps to raise active, usable T3 levels.

Women need at least 8 mg of zinc and 900 mcg of copper. The ratio is important. Test these two nutrients and find out if you have the right ratio, which is .85 zinc:1.2 copper. The level of each mineral in your blood does not matter nearly as much as the ratio.

Many kinds of fish and shellfish are rich in copper and zinc. A medium oyster provides 76.3 mg of zinc and 670 mcg of copper. A 3-ounce serving of crab provides 4.7 mg of zinc and 585 mcg of copper. Shrimp is also a good source of both. Fish such as salmon, catfish, orange roughy and tuna provide copper and zinc.

A 3-ounce serving of cooked beef liver contains 4.5 mg of zinc and 12,049 mcg of copper. Beef, chicken and turkey are also good sources of both of these minerals. Cow’s milk products provide zinc but not copper.

Vegetarians and vegans are especially at risk for zinc and copper deficiency. Many nuts and seeds are rich in zinc and copper, but you would need to eat a large quantity to get the amount your body needs.

High quality multi-vitamins such as contain zinc and copper in good ratios. Some women need higher doses of zinc.

Vitamins C, B12 and B2

Of these vitamins, the one most likely to be low is B12. This is often the case for vegetarians and even more so with vegans. You cannot get vitamin B12 from plant foods. Vitamin B12 levels are very important to test.

Reports show that B12 depletion in the U.S. and Canada occurs in 14–16% of those aged 20–59, and in greater than 20% of those 60 years and older.

If you are low in vitamin B12, it will affect far more than your thyroid function. If you are low in B12, take a high-quality methylated supplement. Or, a methylated B-Complex, which will also have B2.

Foods highest in B12, in this order, are clams, lamb liver, beef liver, duck liver, oysters, duck liver, caviar, mackerel, herring, chicken liver, mussel, crab, sardine, and salmon.

Vitamin C rich fruits include papaya, strawberries, pineapple, orange, kiwi, cantaloupe, raspberries, blueberries, and cranberries. Vegetables include bell peppers, broccoli, brussel sprouts, cauliflower, Bok choy, kale, and cabbage. With supplementation, I highly recommend liposomal Vitamin C, because it is almost 100% absorbed and easy on your digestion.

Eat enough protein for your thyroid

Thyroid hormones are primarily made by the building blocks iodine and tyrosine. Tyrosine is an amino acid that you get in your diet from protein foods. You can also take tyrosine as a supplement alone, or in thyroid formulas. Tyrosine has the additional benefit of supporting your dopamine levels.

In the next post I dig into hypothyroidism caused by poor conversion of T4 to T3. Need help with your thyroid? Please reach out!

Please chime in below,

paris healing arts, doctor laura paris, dr. laura paris, dr laura paris

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  1. Hello madam thanks for sharing such a great information. I have hypothyroid and am using thyroxine tablets, If I send u my lab report would you plz do me the favour by reply with your suggestion

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