The thyroid is the butterfly-shaped gland in our throat that is an essential regulator in our body. It produces thyroid hormone (TH), which affects virtually every one of our cells and is a contributor to metabolism and keeping us energetic and active. When it is producing TH in appropriate quantities, it holds many organs and systems in equilibrium. We know that there is close communication between the endocrine and immune systems and that alteration in levels of TH can affect the function of the immune system. Thyroid hormones also have a role in inflammation, autoimmunity and clearing pathogens from the body. In what may seem like a strange occurrence, the immune system can also attack the thyroid, however.

Autoimmune Thyroid Disease

Autoimmune thyroid disease is not one disease, it refers to several different ways that the immune system can impact the thyroid.

You may have heard from someone you know that their thyroid is overactive or underactive. If it’s overactive, your body is producing too much TH, and you may be sweaty, anxious and lose weight without meaning to. A hypoactive or underactive thyroid is more common, especially in middle-aged women, and leads to the whole system slowing down and producing the following symptoms:

• Sensitivity to cold
• Unexplained weight gain
• Fatigue and sluggishness
• Brittle nails, hair loss, dry skin
• Muscle aches, weakness, joint issues
• Constipation

Low levels of TH can also lead to cardiovascular effects such as high blood pressure, elevated levels of cholesterol and reduced blood flow to vital tissues from the heart’s impaired ability to pump. It can also lead to mental effects, such as difficulty concentrating, and even depression and memory loss. Younger women may develop very heavy periods and infertility.

Hashimoto’s Thyroiditis

Hashimoto’s thyroiditis causes most hypothyroidism. It’s a term that refers to inflammation within the thyroid gland because the immune system is making antibodies that attack it. The attack may cause the thyroid to shrink and lose its ability to make adequate TH or to enlarge and form a goiter. Researchers haven’t determined what causes the immune system to “go rogue” in every situation, but it tends to run in families and is associated with other autoimmune diseases, such as diabetes. In people with genetic susceptibility, it can be triggered by factors such as pregnancy or cigarette smoking. Surgery, radiation treatment, and some medications can also lead to Hashimoto’s thyroiditis. Hashimoto’s thyroiditis is medically treatable with synthetic thyroid hormone.

Stress, Thyroid Function, and Immunity

The adrenal glands are another part of the endocrine system that produces hormones impacting major metabolic processes, just like the thyroid. They can also regulate the immune response. When you are stressed, your adrenals produce stress hormones, including cortisol. When this happens, your body redirects its functions to deal with it, and this includes hormone production and immune response. In our hectic lives, a state of chronic stress can leave us with adrenal fatigue, and this can negatively impact the thyroid, which slows down, causing hypothyroid symptoms. Inflammatory cells, called cytokines, can also make thyroid receptors malfunction. By attempting to overcoming the stressor and the inflammation, your body’s immune system becomes suppressed. A suppressed immune system can trigger not only infection but also autoimmune thyroid disease.

Subclinical Hypothyroidism

In recent decades, researchers have identified a condition that is less severe than clinical hypothyroidism, but which causes essentially the same symptoms. Subclinical hypothyroid symptoms can occur when blood levels show relatively normal TH; it affects 15% of the elderly and may go undiagnosed. Supporting underactive thyroid and adrenals is possible, however, and recommended for those operating under chronic stress. In this situation, optimizing one’s thyroid production via dietary and lifestyle management can improve quality of life. Examples include specific amino acids and adaptogenic herbs known to promote a healthy thyroid and stress response, as well as learning to manage stress.