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What Causes Thyroid Nodules To Grow?

What Causes Thyroid Nodules To Grow and What To Do About It

Key Takeaways
  • Thyroid nodules may grow if they are cancerous or if you have thyroid autoimmunity, iodine deficiency or excess, or thyroid cysts.
  • Improving your gut health and optimizing your iodine intake may slow thyroid nodule growth or resolve nodules altogether.

Your thyroid is a butterfly-shaped gland located in the front of the neck near your Adam’s apple. The thyroid gland is part of your endocrine system. It produces hormones to regulate many of your body’s functions, including energy production, digestive function, body weight, and temperature.

A thyroid nodule (lump) that continues to increase in size can affect your thyroid health. And while most thyroid nodules are benign and don’t cause symptoms, they can indicate an active thyroid problem that could lead to permanent damage of your thyroid gland.

What Is a Thyroid Nodule?

What causes thyroid nodules to grow: Illustration of a healthy thyroid next to a thyroid nodule

Thyroid nodules are lumps inside the thyroid gland. Thyroid nodules can be solid, and when filled with fluid, they’re called thyroid cysts.

What Causes Thyroid Nodules To Grow?

There are four main reasons why a thyroid nodule would grow:

  1. Thyroid cancer
  2. Thyroid autoimmunity
  3. Iodine deficiency or excess
  4. Thyroid cysts

If your thyroid nodule is growing actively, it’s important to determine the reason for this problem and to address it. We’ll take each reason in turn.

Thyroid Cancer

A thyroid nodule that is hard, fixed, painful, or growing may be a sign of cancer in the thyroid cells. Make an appointment with your doctor if you have one of these indicators of thyroid cancer:

  • You have a large, painful, or growing thyroid lump.
  • You have symptoms of pressure in your throat such as hoarseness, difficulty swallowing, a sensation of pressure on your windpipe, or a persistent cough.

These symptoms may indicate thyroid cancer and should be addressed right away. However, most thyroid nodules are noncancerous. [1]

Thyroid Autoimmunity

One of the most common reasons for benign nodules is autoimmune thyroid disease, especially Hashimoto’s thyroiditis. [2, 3] The autoimmune process can cause inflammation and thyroid tissue scarring, which may lead to thyroid enlargement and the development of nodules.

Although an autoimmune attack inflames your thyroid, you usually won’t experience autoimmune symptoms in your thyroid gland. More commonly, you’d see one of the following:

  • Symptoms of hypothyroidism (underactive thyroid) such as fatigue, weight gain, dry skin, or depression
  • Symptoms of hyperthyroidism (overactive thyroid) such as irregular heartbeat, unexplained weight loss, anxiety, and elevated blood pressure
  • No symptoms at all

Thyroid nodules are commonly found during an unrelated physical exam. If your doctor discovers thyroid nodules, be sure to mention any hypothyroid or hyperthyroid symptoms you are experiencing. Getting the right thyroid blood tests, screening exams, and treatment for thyroid autoimmunity is key to improving thyroid nodules.

Iodine Deficiency or Excess

Your thyroid gland needs the right amount of iodine to function. A deficiency or oversupply of iodine can cause thyroid nodules and goiter (an enlarged thyroid gland) and can cause them to grow. Optimizing your iodine intake may help control goiter and nodule growth and reduce thyroid autoimmunity.

Thyroid Cysts

Thyroid cysts are fluid-filled or partially fluid-filled lumps in the thyroid gland. They can be formed from deteriorating thyroid adenomas, which are benign thyroid tumors. They can also occur as part of solid thyroid nodules.

Thyroid cysts may expand without treatment, or they may resolve on their own. If a thyroid cyst is rapidly growing or has a solid component, it should be evaluated to rule out cancer. Methods of evaluation include by an endocrinologist through a physical examination, a biopsy done through fine needle-aspiration, and/or a thyroid ultrasound (thyroid scan). Some thyroid cysts may require treatment.

2 Ways to Improve Thyroid Nodules

Conventional treatment for thyroid nodules may include thyroid-damaging treatments, such as radioactive iodine or surgery. However, you may be able to reduce or eliminate your thyroid nodules by addressing their root cause.

If your thyroid nodule is benign, there are two main treatment options that may help:

  1. Improve your gut health.
  2. Optimize your iodine levels.

Improve Gut Health to Reduce Thyroid Nodules

One of the most common risk factors for thyroid nodules is thyroid autoimmunity, especially Hashimoto’s disease.

Typical treatment for an autoimmune hypothyroid condition is thyroid hormone replacement therapy. [4] This helps resolve symptoms but does nothing to address the underlying autoimmunity. Preliminary research suggests gut health and thyroid health are closely connected. In some cases, addressing your gut health can improve thyroid autoimmunity. [5, 6, 7]

The good news is improving your gut and thyroid health can often be done in these two simple steps:

  1. Eat an anti-inflammatory diet
  2. Take high-quality probiotic supplements

1. Eat an Anti-Inflammatory Diet

A low-quality diet is typically the single biggest source of inflammation for your body and can negatively impact your thyroid function and immune system.

Decreasing the burden of inflammation in your body is helpful for managing almost any thyroid problem, as inflammation is associated with thyroid conditions. [8, 9, 10, 11, 12]

One small study found the Autoimmune Paleo diet reduced thyroid symptoms and inflammatory markers, [13] and many clinicians have seen positive results from using the Autoimmune Paleo diet with their autoimmune thyroid patients. Thyroid nodules may have the potential to stop growing and may even resolve once thyroid inflammation is reduced or eliminated.

2. Take High-Quality Probiotic Supplements

Probiotics can powerfully balance your gut microbiome and repair your gut environment with few side effects. [14, 15, 16, 17] Preliminary evidence shows they can promote optimal thyroid hormone levels and decrease thyroid symptoms. [18, 19] For more about how to use probiotics, see our Probiotics Starter Guide.

Optimize Iodine Levels to Improve Thyroid Nodules

Thyroid hormone is made up in large part by iodine, which has led some clinicians to recommend iodine supplementation to support thyroid health. However, we need to get just the right amount of iodine. The American Thyroid Association states, “Iodine deficiency, which is very uncommon in the United States, is…known to cause thyroid nodules.” However, too much dietary iodine can increase the risk of goiter, multinodular goiter, nodules, and thyroid autoimmunity, especially in Hashimoto’s thyroiditis. [20, 21, 22, 23, 24, 25]

To learn more about how to assess your iodine levels, check out our blog.

The Bottom Line

Most thyroid nodules grow due to thyroid autoimmunity or iodine deficiency or excess, but cancer can also cause a small percentage of cases. If your thyroid nodule is growing, make an appointment to see your doctor. Balancing your iodine levels and improving your gut health with an Autoimmune Paleo Diet and probiotics may help reduce thyroid nodules.

➕ References
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  9. van der Poll T, Romijn JA, Wiersinga WM, Sauerwein HP. Tumor necrosis factor: a putative mediator of the sick euthyroid syndrome in man. J Clin Endocrinol Metab. 1990;71(6):1567-1572. doi:10.1210/jcem-71-6-1567
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  13. Abbott RD, Sadowski A, Alt AG. Efficacy of the Autoimmune Protocol Diet as Part of a Multi-disciplinary, Supported Lifestyle Intervention for Hashimoto’s Thyroiditis. Cureus. 2019;11(4):e4556. Published 2019 Apr 27. doi:10.7759/cureus.4556
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