The effects of an unbalanced gut microbiome, such as increased gas production, changes to digestion and the presence of certain gut bacteria, could alter your risk of acid reflux.
Equally, the effects of reflux and its treatment could influence the balance of microbes in your gut.
This isn’t to say that having an unhealthy gut will always lead to acid reflux, or that reflux will lead to an imbalance of your gut microbes. But the relationship between your gut microbiome and acid reflux is a two-way street.
We investigate this relationship and describe what you can do to support your gut health and protect against the effects of reflux.
What is acid reflux, and why does it happen?
Acid reflux means that acid from your stomach moves up into your oesophagus, the pipe that carries food from your mouth to your stomach.
Reflux can happen for several reasons. There may be an issue with the lower oesophageal sphincter, a ring of muscle at the top of your stomach which controls the passage of food. Other problems with your stomach or acid production could also lead to acid rising up.
The main symptom of reflux is heartburn, a burning sensation in your chest. Reflux may also cause bloating, coughing and a sour taste in your mouth.
If you regularly experience acid reflux, doctors may diagnose gastro-oesophageal reflux disease, or GORD. In the United States, this is known as GERD.
Learn about foods that can trigger or worsen acid reflux.
What does your gut microbiome do in digestion?
The community of microbes living in your gut, your gut microbiome, plays a supporting role in digestion.
These microbes break down parts of foods that otherwise can’t be digested, such as fibre.
Through fermentation, they also produce beneficial compounds, like short-chain fatty acids, which fuel gut cells, support the gut’s lining, and suppress the growth of potentially harmful microbes. Some may even help ease gut-related symptoms.
If the populations of healthy and unhealthy microbes in your gut microbiome become unbalanced, these processes can be disrupted.
This imbalance is known as dysbiosis, and some research suggests it may play a role in the development of certain health conditions.
Learn more about what short-chain fatty acids do.
Is there a link between the microbiome and reflux?
The relationship between acid reflux and the gut microbiome runs both ways: one can affect the other. Let’s take a look at how.
How can changes in your gut microbiome affect acid reflux?
Gut dysbiosis can lead to changes in your gut and digestion. These effects may make reflux more likely.
Gas buildup
If your gut has a large number of unhealthy bacteria, they ferment undigested food in a way that produces gases such as hydrogen and methane.
These gases could increase pressure in your gut, which may encourage stomach acid to move up into your oesophagus. This becomes more likely if your lower oesophageal sphincter isn’t working properly.
One form of dysbiosis that can lead to this gas buildup is known as small intestine bacterial overgrowth (SIBO). It means that large numbers of bacteria live in your small intestine and ferment carbohydrates when they reach this area of your gut.
Other factors that can contribute to this gas buildup include consuming fizzy drinks and highly fermentable fibres, like those in onions and garlic.
Slower food movement
Some emerging research suggests a link between dysbiosis and delayed gastric emptying, which is when food moves from your stomach to your small intestine more slowly than usual.
This reduced pace can increase pressure in the stomach, making it more likely for food and stomach acid to travel up into the oesophagus.
Some research has involved animals rather than humans, and not all studies agree. We need more research to shed light on the current findings.
Presence of specific bacteria
A 2024 study suggests that certain families of gut bacteria directly affect your likelihood of experiencing acid reflux.
The researchers concluded that certain microbes in your gut could either help protect against GORD or increase your risk of it.
How could acid reflux impact your gut microbiome?
If you have acid reflux, or you’ve been diagnosed with GORD, doctors may prescribe proton pump inhibitors (PPIs). These medications reduce the amount of acid your stomach produces.
But stomach acid keeps levels of gut bacteria in check, making it harder for new microbes to contaminate your gut and disrupt its microbiome.
So, if you have low levels of stomach acid due to PPI use, it becomes easier for unhealthy bacteria to grow in areas like the small intestine. This dynamic can lead to SIBO.
Causes and risk factors for reflux and dysbiosis
Acid reflux and dysbiosis share a number of causes and risk factors. Many relate to our daily routines, including what we eat and drink.
The risk factors for both reflux and dysbiosis include:
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High-sugar diets: Consuming lots of simple sugars can increase your risk of GORD and cause unhealthy changes in your gut.
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Low-fibre diets: Fibre is an important fuel for the healthy bacteria in your gut, and eating plenty of fibre can also reduce your risk of GORD.
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High-fat diets: Some research has associated high-fat diets with changes in the gut microbiome and an increased risk of Barrett’s oesophagus, a condition that results from reflux.
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Nicotine: Smoking can increase your risk of GORD and contribute to an imbalanced gut microbiome.
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Lack of exercise: Regular physical activity helps support healthy gut bacteria and is associated with a lower risk of developing GORD.
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Alcohol: Alcoholic drinks may trigger or worsen reflux symptoms and contribute to changes in the balance of your gut microbiome.
Low levels of stomach acid can also contribute to both acid reflux and dysbiosis.
Your body may not make enough stomach acid due to:
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long-term PPI use
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infection with Helicobacter pylori bacteria
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a condition called atrophic gastritis
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thyroid issues
If your level of stomach acidity isn’t high enough, it can lead to:
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belching and bloating
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unhealthy bacteria growing and spreading within the gut
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an imbalanced microbiome
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an increased risk of gut infections
Can supporting your gut health help with acid reflux?
Doing things that are good for your gut health may help with acid reflux, given the close relationship.
Here are a few gut health strategies that might also improve reflux symptoms:
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eating a balanced diet and avoiding triggers
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limiting alcohol, if you drink
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avoiding cigarette smoke
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building movement into each day and trying to meet weekly physical activity recommendations
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not eating too close to bedtime
Eating late in the evening can mean that your stomach is still active when you’re lying in bed. This makes it easier for acid to rise up, and it gives your gut less time overall to rest and recover.
We should note: the foods and drinks that can trigger acid reflux vary from person to person. Identifying your triggers is an important step towards limiting your reflux symptoms.
Learn more ways to support your gut health.
When to seek medical advice
You can prevent and relieve many cases of heartburn (a main symptom of acid reflux) by changing your diet and routine. But in some situations, you may need medical care.
If reflux doesn’t go away, a pharmacist may be able to help by prescribing medication to neutralise your stomach acid (antacids) or reduce the likelihood of the acid rising (alginates).
You should contact your GP if any of the following occur:
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You’re unable to relieve your symptoms with routine changes or medication.
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You’re experiencing heartburn most days.
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You’re experiencing other symptoms, too, such as vomiting, unexplained weight loss, or trouble swallowing.
Frequently asked questions
Here are answers to some common questions about reflux and the gut microbiome.
Can gut bacteria cause acid reflux?
An imbalance in your gut microbiome may slow the movement of food through your gut, which can increase pressure in your stomach. Also, some research links certain gut bacteria with a higher risk of reflux.
Meanwhile, unhealthy gut bacteria may contribute to acid reflux by fermenting food and producing gas in your gut that increases pressure in your stomach. This pressure can make it more likely for acid to rise towards your throat.
Is reflux a gut health issue?
Yes, reflux is considered a gut health issue because it affects the oesophagus, the tube that carries food from your mouth to your stomach. Your gut is really your entire digestive system, from your gums to your bum.
The relationship between reflux and the gut microbiome is a two-way street, so changes with one could affect the other.
Can probiotics help with heartburn?
Some initial findings suggest that certain probiotics could help relieve heartburn. However, more research is needed, and the existing findings don’t propose that probiotics are a solution to reflux.
If you’re otherwise healthy, probiotics are a low-risk thing to try. However, there are many proven ways to relieve heartburn that you could try instead.
Summary
There’s a close relationship between acid reflux and your gut microbiome. Changes in the balance of microbes living in your gut may affect your risk of developing reflux. And some treatments for reflux could lead to changes in your gut microbiome.
Many factors that could increase your risk of reflux can negatively affect your gut health. So, taking steps to support your gut may help keep stomach acid where it belongs.
Pay attention to what, how and when you eat, and how much you move. You’ll be on the right track to a healthy, harmonious gut.
To learn more about other gut health topics, visit Symprove’s Gut Hub.
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