Some research suggests an indirect link between the thyroid gland and acid reflux. However, more research is needed to establish a direct link between the two.

Acid reflux occurs when acid from your stomach flows back up into your esophagus, which is a tube that connects your mouth to your stomach.

It’s common to experience acid reflux from time to time, but regular acid reflux may be a sign of gastroesophageal reflux disease (GERD).

Near the top of the esophagus, in your neck, lies your thyroid gland.

This butterfly-shaped gland is responsible for making hormones that regulate your body’s metabolism. Sometimes, your thyroid may produce too many hormones (hyperthyroidism) or too little (hypothyroidism).

It’s possible to experience short-term acid reflux if you have either thyroid condition. Similarly, you could receive diagnoses of both GERD and a thyroid condition.

However, very limited research suggests a direct link between the thyroid and acid reflux.

Keep reading to learn more about the possible connection between acid reflux and the thyroid.

The most common cause of acid reflux is when the lower esophageal sphincter (LES) doesn’t close properly.

The LES is the muscle located between the esophagus and the stomach. When it gets weak, it may fail to close completely, allowing stomach contents and digestive juices to come back up the esophagus.

Some research suggests that hypothyroidism may impact the function of the esophagus muscles. A buildup of acid in the esophageal muscle tissues may cause the LES to become weaker and more relaxed.

A 2014 study also found that LES relaxation was significantly lower in participants with hypothyroidism compared with those with normal thyroid levels.

LES relaxation might increase the risk of acid reflux occurring.

However, it’s important to note that limited research has examined the direct impacts of hypothyroidism on the LES.

Some research suggests the link between thyroid disease and GERD may be due to problems with the digestive system rather than long-term esophageal exposure to stomach acids.

A 2018 study suggests that GERD may be caused by impaired gastric emptying and esophageal clearing. These are related to how long it takes for food to move through your digestive system. If food lingers in your esophagus and stomach for too long, you may experience symptoms of GERD.

The 2014 study mentioned above also found that hypothyroidism may impact the way food moves through the esophagus.

Sometimes, you may experience acid reflux as a result of taking certain medications.

A 2021 study looked at the effects of taking allopurinol on a number of conditions. Long-term use of this medication is associated with increasing thyroid-stimulating hormone (TSH).

The researchers found that GERD was the second most common diagnosis after TSH treatment.

A 2016 study also found heartburn to be a common symptom of radioactive iodine treatment for thyroid cancer.

A 2020 review found that people with GERD are more likely to experience GERD symptoms if they also have thyroid disease.

The most common symptoms of acid reflux and GERD are heartburn and a bad taste in your mouth.

That said, limited research suggests that GERD-like symptoms may be the first signs of thyroid disease, including:

When these symptoms are present due to thyroid disease, the cause is not GERD but rather the enlarged thyroid gland causing compressive symptoms.

Mental health

A 2021 study found that having GERD and thyroid dysfunction may impact your mental health and quality of life.

Thyroid hormones directly help regulate your mood, and both hyperthyroidism and hypothyroidism have been linked to mental health conditions like depression and anxiety.

GERD is also associated with a higher prevalence of stress, anxiety, and depression. The stress caused by depression and anxiety could exacerbate acid reflux symptoms.

Learn more about stress, anxiety, and acid reflux.

Another possible link between acid reflux and hypothyroidism may be due to Hashimoto thyroiditis.

This autoimmune disease is the most common cause of hypothyroidism. In rare cases, it may cause heartburn due to esophageal dysmotility.

That said, more research is needed to explore the link between Hashimoto thyroiditis and acid reflux.

Can thyroid issues cause acid reflux?

Some research suggests thyroid issues may indirectly cause acid reflux. However, more research is needed.

What is a thyroid belly?

A thyroid belly refers to potential weight gain around the abdominal area that may be caused by hypothyroidism.

What are the symptoms of thyroid burnout?

Both hyperthyroidism and hypothyroidism may lead to feelings of fatigue, lethargy, and sluggishness.

Acid reflux is an uncomfortable feeling that happens when stomach acids go back up the esophagus.

Some research suggests it may be indirectly associated with the thyroid, but more research is needed.

Speak with a healthcare professional if you experience frequent symptoms of thyroid disease or acid reflux. They could provide a proper diagnosis and develop a treatment plan for your condition.