Iodine is a building block and primary raw material for thyroid hormone production. Your thyroid gland needs iodine from your diet in order to produce thyroid hormone. A subset of the American public is iodine deficient, which puts them at greater risk of developing thyroid conditions. Ideally, you should have a urinary iodine clearance test to evaluate for iodine deficiency. If you are deficient, talk with your doctor about supplementing your diet with an iodine/iodide supplement such as Iodoral tablets or Lugol’s solution.

You need to be careful about supplementing with iodine if you are not deficient. Research shows that long-term exposure to excessive iodine levels can trigger or worsen thyroid conditions, including goiter, nodules, hyperthyroidism, hypothyroidism, and Hashimoto’s thyroiditis.

Vitamin D deficiency is linked to an increased risk of Hashimoto’s thyroiditis and to hypothyroidism. Experts recommend that practitioners check vitamin D levels in all their thyroid patients, and address any deficiencies.

Vitamin D deficiency is defined as a vitamin D-25 level of less than <25 nmol/L, but some experts feel that for thyroid patients, the cutoff should be higher, at <60 or 70 nmol/L.

It’s difficult to get enough vitamin D from a combination of diet and sun exposure, so supplementation is often needed.

If you supplement with vitamin D, experts recommend that you take it with your highest-fat meal of the day, often dinner, for best absorption.

The mineral selenium helps your thyroid produce thyroid hormone, convert T4 into T3, and can lower thyroid peroxidase antibodies. Selenium deficiency is also linked to worsening of thyroid eye disease and an increased risk of postpartum thyroid problems. Experts recommend that selenium levels be evaluated in thyroid patients. Selenium is difficult to get from foods, except for the selenium-rich Brazil nut. If your levels are low, talk to your doctor about supplementing with 50 to 100 mcg/day.

Researchers recommend selenium supplementation for Hashimoto’s patients. They wrote:

"Even if a patient with Hashimoto’s is being treated with levothyroxine, some studies found that giving selenium — no more than 200 mcg/day — as well as levothyroxine resulted in a greater reduction in thyroid antibodies (TPOAb)."

Too much selenium supplementation — or high intake of selenium from the combination of food and supplements — can be toxic. To avoid toxicity from selenium, you should never exceed more than 400 mcg of selenium daily from all sources.

Your gut is a key part of your immune system, and “leaky gut” can affect the development and progress of an autoimmune disease. Many practitioners recommend taking a probiotic supplement. Probiotics are the good bacteria that help maintain a healthy intestinal balance for optimal immune function and digestion.

Even if you eat and drink a substantial amount of probiotic-rich fermented foods — like yogurt, miso, sauerkraut, kombucha, and kimchi — you may benefit from a probiotic supplement.

There are many probiotics you can choose. ConsumerLab has a helpful summary. Spore-based probiotics are also gaining attention for their benefits and effectiveness. To learn more, microbiologist and probiotics expert Kiran Krishnan breaks it down in a video.

The amino acid tyrosine is essential to the production of thyroid hormone, as well as T4 to T3 conversion. Tyrosine comes from protein-rich foods, but many thyroid patients benefit from tyrosine supplementation. Some experts recommend that thyroid patients take around 200 to 300 mg of tyrosine supplements daily.

The mineral zinc is important for processing of thyroid hormone, T4 to T3 conversion, and in supporting thyroid function. Low levels of zinc are a known trigger for hypothyroidism. Make sure your multivitamin includes zinc, or consider adding a zinc supplement — experts recommend 15 to 30 mg daily.

The mineral iron is crucial to the healthy functioning of your thyroid and hormones. Specifically, low iron levels are associated with higher risk of subclinical hypothyroidism and reduced T4 and T3 levels.

A key way to evaluate iron status is to have your ferritin measured. Ferritin is a stored form of iron that helps your hormone balance and converts into circulating iron as needed in the body. If ferritin is low, you should supplement with iron.

Iron deficiency is also a key contributor to fatigue and hair loss in thyroid patients. If you are fatigued, and/or you are noticing increased hair loss and shedding, have your ferritin levels tested. Experts recommend that your ferritin levels be in the high end of the laboratory reference range in order to counteract hair loss caused by iron-deficiency.

Supplementing with iron can cause nausea, stomach pain, and chronic constipation. If you don’t tolerate regular iron supplements, consider the Floradix line of iron products, which include tablets and a liquid form of iron. Floradix iron products are often recommended by holistic practitioners because they are typically gentler on the stomach and less likely to cause constipation when compared to typical iron tablets.

Thiamine — vitamin B1 — helps to metabolize carbohydrates into energy. When levels are low, you feel tired and have difficulty concentrating. Thiamine deficiency is more common in people with autoimmune diseases, including thyroid conditions. If you are a thyroid patient and fatigued, consider taking the advice of researchers and supplement with 600 mg of thiamine daily. One study found that after just three days of thiamine supplementation, most patients had a partial or complete elimination of fatigue.