Selenium Benefits For Thyroid Health (Hashimoto’s Thyroiditis)

If you had to guess which mineral can have the biggest effect on your thyroid gland, what would you choose?

Probably Iodine, right?

While iodine is extremely important to thyroid health, selenium is easily just as vital! This little-known mineral can have a big impact on your health, especially if you have Hashimoto’s Thyroiditis.

Keep reading to discover why selenium is so important, how it works with iodine, and the benefits and risks associated with supplementation.

What is Selenium?

Selenium is an essential trace mineral. This means your body cannot make selenium and that it must be obtained from food, but only in very small amounts.

This trace mineral is important for many functions throughout the body. It is needed to create DNA, or the genetic material located within your cells. It protects your body against infection and the damaging effects of free radicals. It is also important for maintaining reproductive health.

Along with these roles, selenium is also crucial to the functioning of your thyroid gland.

Why Does The Thyroid Gland Need Selenium?

You probably hear a lot about iodine in regards to thyroid health, but selenium is easily just as important for proper thyroid functioning.

Levels of selenium are higher in the thyroid gland than anywhere else in the entire body. In fact, the body will prioritize the thyroid gland during a selenium deficiency at the expense of other tissues.

Selenium is needed to make many important enzymes involved in the production and conversion of thyroid hormones. Enzymes are proteins that speed up chemical reactions in the body.

Enzymes that are made up of selenium and cysteine, an amino acid, are used to convert the inactive T4 hormone to the active T3 hormone. This is done by removing an iodine molecule.

Other enzymes made of selenium prevent T4 from being activated when enough T3 is present in the body. This is supposed to prevent conditions like hyperthyroidism from developing.

Some enzymes made of selenium convert hydrogen peroxide, a harmful byproduct of certain reactions in your body, into harmless water. This protects the thyroid because hydrogen peroxide can damage the thyroid gland.

SELENOS, a specific selenium enzyme that has been studied recently, is needed to control inflammation within cells. People with a genetic mutation involving this enzyme have been shown to be at an increased risk of developing Hashimoto’s Thyroiditis.

What Is The Link Between Selenium And Hashimoto’s?

High iodine intake is thought to be a major contributor to the development of Hashimoto’s Thyroiditis. This is a type of thyroid disease that is caused by an autoimmune reaction.

Because iodine and selenium work closely together, selenium deficiency has the potential to make high levels of iodine even more harmful. In fact, getting enough selenium through diet can prevent Hashimoto’s from occurring, even when there is too much iodine in the body.

For people who have already been diagnosed, taking selenium in combination with the synthetic thyroid hormone levothyroxine can reduce inflammation in people with Hashimoto’s.

What Are The Signs Of A Selenium Deficiency?

The signs of a selenium deficiency can look a lot like the symptoms of hypothyroidism. This makes sense, considering low levels of selenium are one of the causes of Hashimoto’s Thyroiditis. Signs of a selenium deficiency include:

  • Hair loss
  • Fatigue
  • Weakness
  • Brain fog
  • Getting sick more often
  • Infertility

Diseases Associated With A Selenium Deficiency

Keshan Disease. This is a reversible heart disease caused by selenium deficiency. It is normally seen in areas where soil levels of selenium are low, especially certain towns in China.

Kashin-Beck Disease. Also known as Big Bone Disease, Kashin-Beck is thought to be caused in part by a selenium and iodine deficiency. It is also common in areas where both of these minerals are lacking in soil.

Hashimoto’s Thyroiditis. This autoimmune form of hypothyroidism is thought to be caused mainly by too much iodine coupled with too little selenium.

Cancer, Heart Disease, and Type II Diabetes. Selenium has been shown in observational studies to be related to an increased risk of heart disease and Type II Diabetes. Observational studies can only show associations between two factors, not a cause and effect. More research needs to be done to see if there is a solid relationship between low selenium, heart disease, and Type II Diabetes.

What Is Selenium’s Role In Cancer?

Selenium plays an important role in creating enzymes that get rid of free radicals. Free radicals are a natural byproduct of energy creation within your cells. Even though they are natural, free radicals are very unstable and can damage your body, possibly leading to cancer over time.

Selenium also helps your body recycle antioxidants. Antioxidants can attach themselves to free radicals and prevent them from reacting with your body.

Supplementing with selenium has been shown to reduce the risk of many cancers in people who are already at risk of developing those cancers. These cancers include esophageal, gastric, prostate, colon, liver, and lung cancers.

Even though selenium supplementation helped reduce the risk of developing these cancers, these studies where done in areas where selenium deficiencies are common.  This means that if you’re getting enough selenium through your diet, you’ll likely reap the same cancer-reducing benefits as the people in these studies.

Can Selenium Cause Weight Loss?

If you have a diagnosis of Hashimoto’s Thyroiditis, selenium supplementation has the potential to help with weight loss. This is because it can improve your hypothyroid symptoms as a whole, and one of the common symptoms is unintentional weight gain.

Your thyroid gland regulates your metabolism. When your thyroid gland is moving slowly because of Hashimoto’s, your metabolism will slow down as well. This naturally results in weight gain.

The beneficial effects of selenium on thyroid function can have positive effects on your metabolism and, along with a healthy diet, can possibly help you lose weight if you have Hashimoto’s.

What Are Some Foods High In Selenium?

Selenium can easily be obtained from food. The recommended daily allowance for selenium is 55 micrograms for both men and women. Foods high in selenium include:

  • Brazil nuts
  • Organ meats
  • Seafood
  • Cereals and grains
  • Tofu

Does Selenium Have Any Side Effects?

Normal, short-term supplementation of selenium does cause side effects in most people.

Overdosing on selenium is possible. The tolerable upper intake level for most people is 400 micrograms per day. More than this can cause the following symptoms:

  • Hair loss
  • Skin irritation
  • Diarrhea
  • Nausea and vomiting
  • Weak fingernails
  • Fatigue

Taking selenium supplements long-term, even at lower doses, can increase the risk of developing Type II Diabetes.

Can You Take Iodine and Selenium Together?

You may not want to take iodine and selenium together unless your doctor instructs you to do so.

Iodine is not typically recommended for people with Hashimotos’ Thyroiditis. This is because people with this condition often have an excess of iodine in their system and should be limited the amount of iodine they consume.

Selenium has the potential to reduce the effects of too much iodine, so it is sometimes suggested to take selenium if an iodine supplement has been prescribed. Iodine supplements may be recommended for people with an iodine deficiency or non-Hashimoto’s hypothyroidism.

Should Selenium Be Taken While You’re Pregnant Or Breastfeeding?

A source from Oxford University does not recommend selenium supplementation during pregnancy or while breastfeeding.

This is because the safe range of selenium intake is relatively narrow. Because of this, it is easy to overdose when taking a supplement.

You should easily be able to get enough selenium from your diet without taking a supplement. However, always listen to your doctor’s advice and talk to them before starting any supplements while pregnant or breastfeeding.

Takeaway Notes

  • Selenium is an essential trace mineral that must be obtained from food.
  • Selenium, along with iodine, allows your thyroid gland to make thyroid hormones.
  • Selenium can help reduce the harmful effects of a diet high in iodine and possible prevent Hashimoto’s from developing.
  • Cancer can be caused by the harmful effects of free radicals, and selenium plays a role in the removal of those free radicals.
  • Selenium can be found naturally in Brazil nuts, meats, and grains.
  • Overdose is possible and can include hair loss, fatigue, vomiting, and diarrhea.
Kelli Yates
Kelli Yates
Kelli Yates is a health and nutrition writer, dietetics student, and co-host and creator of The Nutrition Nerds Podcast. In her spare time she teaches the free class Well-Fed Survival: Eating Healthy After A Disaster, which helps people build nutritious emergency food supplies and prepare for natural disasters.
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