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Nutrients to Prevent and Support Hashimoto's

Vitamin D, zinc, and selenium have been shown to reduce symptoms

With Mary Murimi PhD, RD


Nutrients such as selenium and vitamin D have been shown to help prevent and mitigate flare-ups of autoimmune thyroid disorders.

Autoimmune or Hashimoto's thyroiditis is the leading cause of hypothyroidism in the United States. You may know that certain factors put you at an increased risk for developing Hashimoto's, such as gender and heredity. Research also suggests that lifestyle factors may increase or decrease the risk in predisposed individuals, such as those with a parent who has an autoimmune thyroid condition. The good news is that certain nutrients may help prevent or delay the onset of autoimmune thyroiditis: vitamin D, zinc, and selenium. The same nutrients can also decrease symptoms in people with thyroiditis and hypothyroidism.

These key nutrients affect your thyroid health in two major ways. The first is by epigenetics, the changeable expression of your genes based on lifestyle factors such as diet, exercise, and stress. The second is via your body’s inflammatory pathways, which can increase symptoms. While most of life is out of our hands, we can strive to eat a diet rich in the foods that nourish us. To better understand these beneficial dietary practices, EndocrineWeb spoke with Mary Murimi PhD, RD, and professor of nutrition at Texas Tech University.

Vitamin D

  • Helps modulate the expression of immune cells, to maintain a balanced immune response, and decrease the development of pro-inflammatory markers.
  • Reduces autoimmune antibodies and decreases the body’s inflammatory response.

Vitamin D may be the most underappreciated vitamin, especially because it also functions as a steroid hormone, and has many important purposes in the body. One of these is your immune function.

Here's how it works: autoimmune-thyroiditis is mediated by t-cells, or lymphocytes that develop in the thymus and differentiate into sub-types. Vitamin D plays a crucial role in the differentiation and regulation of these immune cells.

Th1 cells are pro-inflammatory and play a role in autoimmune disorders. Adequate vitamin D can decrease the expression of these pro-inflammatory Th1 cells and promote balance with their Th2 cell counterparts. Adequate vitamin D can also reduce your body’s adaptive immune system’s expression of antigens, which can otherwise attack the thyroid in autoimmune disorders.

Several clinical trials have shown a correlation between vitamin D deficiency and thyroid antibodies, along with an inverse relationship between the biological active form of vitamin D levels and thyroid antibodies. Insufficient vitamin D can result in too much or too little of the ingredients necessary for proper immune function. 

Vitamin D also plays an important role in your body’s inflammatory response by promoting the expression of anti-inflammatory cytokines. By reducing inflammation, vitamin D may decrease signs and symptoms of autoimmune thyroiditis.

What about people who already have autoimmune thyroiditis and hypothyroidism? A recent study showed that in hypothyroid patients with low vitamin D levels, supplementation could increase serum 25-hydroxyvitamin D levels with a correlating significant decrease in serum thyroid-stimulating hormone. A subsequent study showed a decrease in thyroid antibodies after supplementation with vitamin D.

Should you take supplements for your thyroid?

Dr. Murimi explains why that depends on a few factors. The first rule of supplementation is knowing if you are deficient. This is especially important with fat-soluble vitamins such as vitamin D. A simple blood analysis can determine the answer.

Our bodies synthesize vitamin D from the sun, and we can obtain it from certain dietary sources, such as fatty fish and egg yolks. Still, vitamin D deficiency is the most common nutrient deficiency in the world and affects at least 40% of adults in the United States.

You can increase vitamin D levels by spending more time in the sun. You can also take vitamin D supplements, but please consult with your doctor for recommended intake, as it varies from person to person.


Zinc, like vitamin D, may play a role in T cell differentiation, and is important for a balanced immune system. In addition to modulating the adaptive immune system’s inflammatory response, zinc can work to inhibit Th17 lymphocytes which may confer susceptibility to autoimmune diseases. A recent systematic review and meta-analysis concluded that zinc levels should be monitored in neo-natal women, preschoolers, and school-aged children, because of its influence on susceptibility for autoimmune diseases.

Zinc can also decrease oxidative stress, and reduce levels of inflammation in the body, helping to slow the progression of autoimmune thyroiditis.

Zinc deficiency isn’t always easy to test for, but your doctor may look for symptoms such as:

  • diarrhea
  • lowered immunity
  • thinning hair
  • decreased appetite
  • mood disturbances
  • dry skin

You may have noticed that many of these symptoms mimic the symptoms of thyroid disorders.

The best way to make sure you have sufficient zinc is by eating a balanced diet that includes food rich in this essential nutrient.

Zinc-rich foods include: 

  • legumes
  • nuts and seeds
  • whole grains
  • eggs
  • kale
  • peas
  • asparagus
  • meat
  • shellfish
  • dairy


Selenium is the only trace element to be specified in the genetic code, and the thyroid has the highest concentrations per gram in your body. Dr. Murimi calls selenium the unsung hero of nutrients, because of its importance in converting thyroxine (T4) to the more metabolically active, triiodothyronine (T3). This suggests that selenium may be especially important for people with developed autoimmune thyroiditis and hypothyroidism.

A recent French study cited in a systematic review and meta-analysis found that sodium selenite supplementation for 12 months may protect against autoimmune thyroid disease. In the study, supplementation with sodium selenite protected against thyroid tissue damage. Meanwhile, a new Italian study demonstrated that a physiological dose of Se, 80μg of sodium selenite over 12 months prevented progression of the disease in patients with mild Hashimoto's thyroiditis.

A different systematic review and meta-analysis focused on randomized control studies that tested the effects of selenium supplementation on patients with autoimmune thyroiditis. After 6 months, there was a reduction in TPOAb titers, and after 12 months, there was a reduction in TgAb titers. The review recommended selenium supplementation as an effective complementary therapy for patients with autoimmune thyroiditis.

Selenium deficiency is rare in the United States, but the selenium in foods is dependent on the soil it is grown in. Rainfall and pH levels can affect selenium levels in soil.

Symptoms of selenium deficiency:

  • muscle weakness
  • fatigue
  • mental fog
  • hair loss

Again, all symptoms that are associated with thyroid disorders.

You can increase your selenium intake with foods such as:

  • brazil nuts
  • rice
  • beans
  • whole-wheat bread

If you are concerned you aren’t getting adequate selenium, consult with you doctor and discuss which supplement and dose is best for you.

The National Institute of Health (NIH) recommends 55 micrograms (mcg) of selenium daily, for adults over 14. 

We can’t always control our health, but we can help our bodies stay balanced with a diet rich in variety. Dr. Murimi reminds us that our first line of defense is a healthy lifestyle, rich in nutrient-dense foods. She is also clear that food is not the only part of prevention. Exercise, sleep, and time outdoors are all part of a healthy and balanced life.

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