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Role of TPO Antibodies in Hashimoto's Disease

Thyroid peroxidase (TPO) antibodies mark the presence of autoimmune thyroid disease.
Role of TPO Antibodies in Hashimoto's Disease

In this article:

  • Thyroid peroxidase (TPO) antibodies
  • What is Hashimoto's thyroiditis?
  • Risk of developing autoimmune condition
  • Causes of Hashimoto's thyroiditis
  • Thyroid antibodies without hypothyroidism
  • Diagnosing Hashimoto's thyroiditis?
  • How to lower TPO antibodies

Antibodies are proteins produced by the body to protect against infections. However, sometimes they mistakenly attack against your own tissues, causing illness. The consequence is an autoimmune disease, which causes some thyroid conditions.

What are thyroid peroxidase (TPO) antibodies?

Thyroid peroxidase (TPO) is an enzyme found in the thyroid gland that plays a vital role in the production of thyroid hormones. TPO converts iodide ions absorbed from food into an active form of iodine to be used by the body.

The body needs iodine to make thyroid hormones. Iodine connects with tyrosine (an amino acid) for the production of the thyroid hormones: thyroxine (T4) and triiodothyronine (T3).  If dietary iodine is deficient, the thyroid cannot produce sufficient thyroid hormone. 

This lack of thyroid hormone creates negative feedback with the pituitary gland, which produces and releases thyroid-stimulating hormone (TSH). An increase in TSH signals additional production of TPO. 

If antibodies levels in the blood are elevated, it suggests that your immune system is attacking normal, healthy tissue. 

Typically, the immune system safeguards against germs like bacteria and viruses. It can generally distinguish between foreign cells and your cells. 

However, autoimmunity is a condition in which your immune system mistakenly attacks your body. It mistakes your cells as foreign and releases antibodies that attack healthy cells.

Some autoimmune conditions target only one part of the body, like in the case of autoimmune thyroiditis (also known as Hashimoto's thyroiditis).

What is Hashimoto's thyroiditis?

Hashimoto's thyroiditis is an autoimmune disorder, which means it occurs when immune cells attack healthy tissue instead of protecting it. This disorder is the single most common cause of hypothyroidism in the United States. You will develop hypothyroidism if immune cells damage your thyroid to the point that the gland can no longer produce sufficient thyroid hormones.

Hashimoto's presents two types of antibodies: thyroid peroxidase antibodies (TPOAb) and thyroglobulin antibodies (TgAb). 80-90% of people with Hashimoto's have antibodies present in their bloodstream. 

Risk of developing an autoimmune condition

Science isn't entirely sure why the immune system, which is supposed to defend the body from harmful viruses and bacteria, sometimes turns against the body's healthy tissues.

Some scientists think a virus or bacterium might trigger the response, while others believe a genetic flaw may be involved. A combination of factors — including heredity, sex, and age — may determine your likelihood of developing the disorder.

Causes of Hashimoto's disease

Genetic predisposition

Researchers estimate that 70%–80% of susceptibility to autoimmune thyroid disease is based on a family history of autoimmune diseases, including:

  • Graves' disease
  • Type 1 diabetes
  • Lupus
  • Sjögren's syndrome
  • Rheumatoid arthritis
  • Vitiligo
  • Addison's disease


Pregnancy puts metabolic stress on a woman. The thyroid undergoes noticeable modifications to cope. These changes are typically reversible after birth, though pregnancy can sometimes be a trigger for postpartum thyroiditis. Postpartum thyroiditis is a condition in which the thyroid becomes inflamed within the first year after birth. In most cases, postpartum thyroiditis is limiting to weeks or months after delivery but occasionally develops into Hashimoto's disease.

Other hormonal events

Hashimoto's is seven times more likely to occur in women than men. Hormonal events like puberty, pregnancy, or menopause may contribute to the development of Hashimoto's. 


Hashimoto's may be associated with other autoimmune disorders like celiac diseasetype one diabetesrheumatoid arthritis, or lupus. The condition of having two or more autoimmune conditions is called polyautoimmunity. 

Emotional or physical stress 

Emotional stress can come from feelings of resentment, fears, frustration, sadness, anger, or grief. Physical stress can come from over- or under-eating, over- or under-exercising, smoking, or other bad habits. Stress that's constant and lasts over an extended period may result in a weakened immune system, according to the American Psychological Association.

Nutrient deficiencies

The more dietary stress you put on yourself, the more likely you are to experience inflammation that can worsen your autoimmune reactions and interfere with your thyroid function. Common deficiencies include selenium, vitamin D, nutrient-poor diets, B vitamins, iron/ferritin, iodine, and zinc.

Food sensitivities

Dietary triggers can lead to increased gastrointestinal permeability, chronic inflammation, and a possible elevation in thyroid antibodies. Common sensitivities include gluten, dairy, soy, grains, eggs, nuts and seeds, and nightshade vegetables.

Environmental toxins

Environmental exposure to toxicants may be associated with susceptibility to autoimmune thyroid disease. Common toxins include plastic water bottles (BPA), pesticides, antibacterial in soaps, fertilizer, smoking, and soy products 

Find out which Paloma thyroid doctor is right for you:

Thyroid antibodies without hypothyroidism

In many cases, thyroid antibodies can be the first indication of a thyroid problem. While the presence of thyroid antibodies in the blood does not necessarily mean that a person has fully-developed hypothyroidism, it does mean that there is an ongoing attack against the thyroid. This attack increases your risk for future thyroid disorders.

Many labs look only at Thyroid Stimulating Hormone (TSH) to assess thyroid health, but we believe it is critical to also measure Free Triiodothyronine (fT3), Free Thyroxine (fT4) and TPO antibodies. It's important to monitor thyroid function to take action before the subclinical disease progresses.

Do elevated TPO levels present symptoms?


Autoimmune disease can be progressive. Patients may experience elevated levels of TPOAb for many years before noticing any symptoms.

With progression, the thyroid may grow in size and cause the front of the neck to look swollen. The enlarged thyroid, called a goiter, may create a feeling of fullness or tightness in your throat, though it is usually not painful. 

As Hashimoto's destroys more thyroid tissue, the drop in thyroid hormone production may express symptoms like:

  • Tiredness and fatigue
  • Weight gain
  • Trouble tolerating cold
  • Joint and muscle pain
  • Constipation
  • Dry, thinning hair
  • Heavy or irregular menstrual periods and problems becoming pregnant
  • Feelings of depression
  • Memory problems
  • Slowed heart rate

The thyroid becomes less and less capable of compensating for its thyroid hormone deficiency. In the end stages of Hashimoto's thyroiditis, the gland loses its ability altogether to produce thyroid hormone.  

If you experience symptoms of Hashimoto's like fatigue, dry skin, constipation, or a goiter, a complete blood test can help you understand how your thyroid is working.

Without verifying the presence of thyroid antibodies, these symptoms (or lack thereof) can lead to a missed diagnosis or misdiagnosis of mental health issues, menopause, or even hypochondria. 

Diagnosing Hashimoto's thyroiditis

The diagnosis of Hashimoto's thyroiditis comes from laboratory testing and physical examination.


The most common findings in blood work are elevated TSH and low T4 (thyroxine), in conjunction with elevated TPO antibodies. 

Lab Results

Your complete thyroid blood panel should include TSH, free triiodothyronine (fT3), free thyroxine (fT4), and TPO antibodies. Having this information helps to determine the cause of your under- or over-active thyroid. 

Lab results read as "positive" or "negative" concerning whether or not you have TPO antibodies present in your blood sample. 

If you show a negative result for TPO antibodies, it means that there were no TPO antibodies discovered in your blood. Therefore, if you have symptoms of a thyroid condition, it is unlikely that an autoimmune disorder causes them.

If you show a positive result for TPO antibodies, it may mean you have:

Thyroid Ultrasound

A TPOAb test is not the only indicator of Hashimoto's. A study from California Northstate University suggests that 10% of patients with Hashimoto's may have blood work that is negative for TPO antibodies.


While there is a low probability that you need other tests to confirm Hashimoto's disease, a thyroid ultrasound can help in diagnosis, if necessary. The ultrasound assesses the size of the thyroid, the pattern and structure of tissue, and the presence of nodules. 


Use The Same Laboratory

Autoimmunity and the degree to which your immune system attacks your thyroid can vary much day-to-day. It is also highly sensitive to your lifestyle, including diet, stress, sleep, and exercise. The measure of antibodies can vary based on what's going on in your environment.

Test results are only meaningful when compared to reference ranges. Reference ranges (or "normal" ranges) are the values expected for a healthy person.


Reference ranges vary by lab, meaning that different labs may yield different results. That is normal. While the accuracy of lab testing has significantly evolved, some lab-to-lab variability can still occur due to differences in testing equipment, chemicals used, and analysis techniques. This variability is the reason you should use the range supplied by the lab that analyzed your test to evaluate whether your results are within normal limits.

Use the same laboratory each time you have your labs drawn. Consistency is key. 

How to lower TPO antibodies

High levels of TPO antibodies may be indicative of autoimmune thyroid disease. On their own,, the presence of TPO antibodies does not necessarily mean hypothyroidism. Instead, Hashimoto’s is the most common cause of hypothyroidism. So the presence of thyroid antibodies may predict the risk of developing hypothyroidism, and it may be advantageous to lower antibodies to protect your thyroid gland.


Ahead, a few strategies to help reduce TPO antibodies: 


Try a Paleo or Autoimmune Protocol diet

Common food sensitivities include gluten, dairy, soy, grains, eggs, nuts, seeds, and nightshades. The Autoimmune Protocol (AIP) diet is a way of eating that helps you identify which of these foods may be triggering inflammation in your body.  One study of 17 women between the ages of 20-45 who participated in a ten-week Autoimmune Protocol program shows that identifying your dietary triggers may decrease systemic inflammation and modulate the immune system. 


Supplement with vitamin D

Vitamin D supplementation may reduce TPO antibody levels. One study of 102 patients with newly diagnosed autoimmune thyroid disease shows a significant reduction in TPO antibodies after three months of vitamin D supplementation. 


Supplement with selenium

Selenium supplementation may also reduce TPO antibody levels. One blind, placebo-controlled study of women with autoimmune thyroiditis suggests that selenium supplementation may improve inflammation.


Address other nutrient deficiencies

Other common nutrient deficiencies include B vitamins, iron or ferritin, iodine, or zinc. Work with you doctor to confirm a nutrient-deficient state with lab testing. It is easy to treat with the appropriate supplements.


Remove or avoid environmental toxins

Although about 70% of the risk for developing autoimmune thyroid disease is due to family background, several environmental toxins like radiation, iodine excess, pesticides, or chemical exposure may still trigger TPO antibodies. 


Manage your stress

Stress is anything that disrupts the body’s natural balance (homeostasis), so while this advice may sound trite, stress can affect virtually every system in your body. Stress can be anything from big life shifts or a heavy workload to blood sugar imbalance, too much exercise, reduced sleep quality, environmental toxins, and more. 


Get enough sleep

Not only is sleep important for your overall health, but it's also a powerful form of treatment for autoimmune conditions. Adequate sleep can lower inflammation, heal, and restore damaged tissue.

How to manage a flare-up

Flare-ups occur in autoimmune diseases when a stressor triggers your already compromised immune system. 

An autoimmune flare-up is a period of worsening and intensification of symptoms due to an added stressor on an already compromised immune system.

Symptoms related to a flare-up are generally those already seen with the disease but with much more intensity. Each person experiences a flare-up differently. Some patients have described it as feeling "tired, sore, and beat up," "absolute dragging fatigue," and "utter exhaustion." A flare-up may present a large number of symptoms at a moderate intensity level, or maybe just a few symptoms at a debilitating level.

A flare-up may be the result of increased inflammation of the thyroid, as well as an increase in circulating TPO antibodies due to a heightened response from your immune system. Then, of course, symptoms are more severe as your immune system is waging a battle against your thyroid in response to some form of stress. 


If you are concerned about your thyroid health, schedule a free consultation with a care advisor to determine if Paloma might be the right fit for you.

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The above information is not intended to diagnose, treat, cure, or prevent diseases. We recommend that you work with your Paloma care team to learn how to optimize your thyroid health. 

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