What is the Purpose of the Thyroid?

Theresa Groskopp

thyroid model

The thyroid is a small, butterfly-shaped organ located near the front of the neck. Despite its small size, the thyroid plays a big role in facilitating several important processes in the body. Hormones produced by the thyroid impact metabolism, cardiovascular health, temperature regulation, energy, skin health, mood, and more.

Purpose of the Thyroid

The purpose of the thyroid is to control your body’s metabolism, or the rate at which your body breaks down food and converts it to energy. Our thyroids do this by producing and secreting four specific hormones:
  • Thyroxine (T4), the primary hormone made and released by the thyroid.
  • Triiodothyronine (T3), the hormone that is most strongly associated with metabolism rate.
  • Reverse triiodothyronine (RT3), which reverses the effects of T3 (this hormone is made only in small amounts).
  • Calcitonin, a hormone that helps to regulate calcium levels in the blood.
To make these hormones, the thyroid needs iodine, a mineral found in foods like table salt, fish, and dairy products. While most people in the United States get adequate iodine through diet, too much or too little iodine can cause your thyroid to over or underproduce thyroid hormone.

What is the Most Important Job of the Thyroid?

While thyroid functioning affects several processes and systems within the body, the most important purpose of the thyroid is regulating metabolism. The hormones produced by the thyroid play a significant role in the body’s metabolic processes, which can affect everything from mood and energy levels to weight management to cardiovascular, respiratory, and nervous system health.

Types of Thyroid Disorders

Roughly 20 million people in the United States have a thyroid disorder or condition. Thyroid disorders can be primary, meaning they originate in the thyroid, or secondary, meaning that they can occur as a symptom of a different disease or condition. While there are many different types of thyroid disease, the four most common are:
  1. Hypothyroidism, or an underactive thyroid
  2. Hyperthyroidism, or an overactive thyroid
  3. Goiter, an enlarged thyroid gland
  4. Thyroid cancer, a highly treatable type of endocrine cancer affecting the thyroid

Hypothyroidism vs. Hyperthyroidism

Signs and symptoms of a potential thyroid disorder vary depending on whether the condition is causing the thyroid to produce too much thyroid hormone (hyperthyroidism) or not enough thyroid hormone (hypothyroidism). Hyperthyroidism causes the thyroid gland to produce an excess of thyroid hormones, leading to accelerated metabolism. The most common types of hyperthyroidism are Graves' disease (an autoimmune disorder where the immune system mistakenly attacks the thyroid gland), a toxic nodular goiter, and thyroiditis (inflammation of the thyroid gland). A common type of hypothyroidism in women than in men, which can develop during middle age, is Hashimoto's disease, also known as Hashimoto's thyroiditis, an autoimmune disorder that involves the immune system mistakenly attacking the thyroid tissue, leading to inflammation and damage to the thyroid cells. Over time, this can result in a gradual decline in thyroid function. Treatment usually involves thyroid hormone replacement therapy to address hypothyroidism.

Hyperthyroidism Signs and Symptoms

Common signs and symptoms of hyperthyroidism include:
  • Rapid heart beat
  • Feeling shaky, nervous, or anxious
  • Unexplained weight loss (often despite increased appetite)
  • Insomnia
  • Intolerance to heat; excessive sweating
  • Diarrhea or frequent bowel movements

Hypothyroidism Signs and Symptoms

Common signs and symptoms of hypothyroidism include:
  • Fatigue and lethargy
  • Weight gain
  • Numbness or tingling in the hands
  • Widespread muscle pain or weakness
  • Constipation
  • Depression
  • Dry skin
  • Intolerance to cold

Can You Live Without a Thyroid?

You can live without a thyroid. In fact, while thyroid cancer treatment regimens will vary depending on the type and severity of the cancer, thyroid cancer treatment will often include removing part of the thyroid (a lobectomy) or the entire thyroid (thyroidectomy). Thyroid removal is fairly common, and while patients who undergo a thyroid lobectomy or a thyroidectomy must take hormone replacement medication for the rest of their life to stay healthy, it is indeed possible to live without a thyroid. If you suspect you may be experiencing thyroid dysfunction, it’s important to talk to your physician. Most thyroid disorders are highly treatable. It's important for individuals with hypothyroidism or hyperthyroidism to work closely with your healthcare provider to manage your condition and monitor thyroid hormone levels regularly. Additionally, managing stress, maintaining a healthy diet, taking the best thyroid supplement to fill any nutritional gaps, and getting regular exercise may contribute to your overall well-being. Read more to learn how to select the best thyroid supplement.
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About the Author

Theresa Groskopp

Certified Nutritionist in Appleton, Wisconsin, Founder of Natural Health Co. Natural health and nutrition advocate. Enjoys gardening, biking, fitness, boating, animals (especially cats), and cooking.

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