Thyroid Autoimmunity – What Are Healthy Levels for Thyroid Antibodies

Thyroid Autoimmunity – What Are Healthy Levels for Thyroid Antibodies - auto

You must reduce elevated TPO antibodies down to the normal reference range to prevent hypothyroidism.

If a recent lab test has shown that you have elevated thyroid antibodies, your next question might be, “How can I bring them down to normal levels?” 

When it comes to thyroid antibodies, striving for perfection may be overrated. Let’s talk about what level of antibodies you should aim for and how to reduce them.

What are Thyroid Antibodies?

Sometimes the immune system mistakenly attacks your thyroid gland with antibodies. This damages your thyroid and can lead to inflammation of the thyroid gland (thyroiditis), symptoms of hypothyroidism or hyperthyroidism, and if left unchecked, autoimmune thyroid disease.

By far, the most common cause of hypothyroidism and elevated thyroid antibodies is the autoimmune disorder Hashimoto’s thyroiditis. Elevated thyroid antibodies are also found in Graves’ Disease.

Hashimoto’s is diagnosed by blood tests looking for:

  • Elevated thyroid peroxidase (TPO) 
  • Elevated thyroglobulin (TG) antibodies (although these are less reliable)

You have autoimmune hypothyroidism if you have elevated thyroid antibodies and also have:

  • Low T4
  • Elevated thyroid stimulating hormone (TSH) levels.

Not everyone who has thyroid antibodies is hypothyroid, but some people with elevated TPO or TG antibodies will eventually become hypothyroid. The question is, how likely is it you will become hypothyroid if your antibodies are elevated?

How Important are Thyroid Antibodies?

Thyroid Autoimmunity – What Are Healthy Levels for Thyroid Antibodies - auto

There is low risk of progressing to hypothyroidism if TPO antibodies are at or below 500 IU/mL [1 Trusted SourcePubMedGo to source].

The “normal” reference range for TPO antibodies is less than 35 IU/mL. But a 2016 study published in the Journal of Hormone and Metabolic Research [1 Trusted SourcePubMedGo to source] found: 

  • Those who had TPO antibodies below 500 IU/mL had a low risk of future progression to hypothyroidism. 
  • Those who were above 500 IU/mL still only had a moderate risk. 

The Tehran Thyroid Study, which followed the course of thyroid disease in a large cohort of people over nine years, showed similar results: those with elevated TPO antibodies only had a 9-19% chance of becoming hypothyroid after 6 years of follow up [2 Trusted SourcePubMedGo to source, 3 Trusted SourcePubMedGo to source].

If we consider this, elevated thyroid antibodies are not as consequential as many thyroid experts would suggest. 

I’ve commonly seen people with Hashimoto’s disease or elevated thyroid antibodies become hyper focused on reducing their antibody test results to the “normal” reference range, and becoming unnecessarily stressed. The research suggests this isn’t necessary. 

Instead, it implies that only a minority of patients with elevated TPO antibodies will progress to full hypothyroidism. What this means for you is that you don’t have to continuously pursue lower and lower levels of antibodies with strict diets or supplements, especially if your thyroid symptoms are under control.

If you’re a patient, or a doctor working with patients, it’s important to understand that reducing TPO antibodies to under 500 IU/mL—or getting your thyroid symptoms under control through other means—is a clinical win.

Very High Thyroid Antibodies

Thyroid Autoimmunity – What Are Healthy Levels for Thyroid Antibodies - AdobeStock 170166574 L

All that said, if your TPO antibodies are very high, reducing your antibody count is definitely a worthwhile goal. The higher the antibodies, the more likely you are to develop hypothyroidism.

The farther you reduce your antibodies, even if you can’t get them down to 500 IU/mL, the less damage to your thyroid gland. Just don’t feel discouraged by failing to get them down to the “normal” reference range.

4 Ways to Reduce Thyroid Antibodies

There are several ways you can reduce your thyroid antibodies and improve your thyroid function, using diet and lifestyle.

1. Improve Your Gut Health

Preliminary evidence suggests that gut health is closely linked to thyroid health, and that improving gut health can decrease thyroid antibodies and balance your  thyroid hormones. Here are several ways you can work on improving your gut health.

Thyroid Autoimmunity – What Are Healthy Levels for Thyroid Antibodies - auto

2. Supplements

3. Light Therapy

There are some encouraging data showing that low-level laser therapy can improve thyroid function and decrease TPO antibodies. The therapy also reduced the amount of levothyroxine medication the patients needed, even after 9 months of follow up [28 Trusted SourcePubMedGo to source, 29 Trusted SourcePubMedGo to source].

4. Optimize Iodine Levels

Iodine is an important nutrient for the thyroid gland, but must be used cautiously. Supplemental dietary iodine has been shown in several population-based studies to increase the incidence of autoimmune thyroid diseases [30 Trusted SourcePubMedGo to source, 31 Trusted SourcePubMedGo to source]. On the other hand, too little iodine can also cause thyroid symptoms. Optimizing your iodine levels may reduce thyroid antibodies.

For more on how to optimize your iodine, including how to test, see How Should I Use Thyroid Supplements?

The Bottom Line

Unless your TPO antibodies are very high, it’s not necessary to be hyper-focused on reducing your thyroid antibodies to the lab reference range. Reducing elevated thyroid antibodies to below 500 IU/mL, and improving your thyroid function with diet and lifestyle changes significantly reduces your risk of developing hypothyroidism.

➕ References
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