Acid Reflux: Why It Happens and What You Can Do About It

Acid reflux is commonly described as a problem of “too much stomach acid.” It is an understandable assumption. If acid is causing the burning sensation, surely reducing the acid must solve the underlying problem?

But reflux is more complicated than that. Stomach acid belongs in the stomach. The stomach has specialised protective mechanisms that allow it to tolerate the strongly acidic environment needed for normal digestion. The oesophagus does not have the same protection.

With reflux, the important question is therefore not only how much acid the stomach is producing, but why stomach contents are moving upwards into the oesophagus in the first place.

The lower oesophageal sphincter, diaphragm, pressure within the stomach, gastric emptying, meal size and timing, body position and other factors can all influence whether reflux occurs. And what moves upwards is not necessarily acid alone. Refluxed material can include food, digestive secretions and enzymes such as pepsin.

This helps explain why two people with apparently similar heartburn may not have exactly the same underlying problem, and why effective management needs to look beyond simply suppressing acid.

In this article, we will look at what acid reflux actually is, what causes acid reflux, how it is assessed and the practical foundations that can help. The central principle is: The problem is often not that stomach acid exists. It is that gastric contents are travelling in the wrong direction and reaching tissues not designed to tolerate them.

Quick Answers

• Acid reflux does not necessarily mean too much stomach acid. Reflux occurs when gastric contents move upwards into the oesophagus.
• The lower oesophageal sphincter and diaphragm work together to form an important anti-reflux barrier.
• Pressure matters. Large meals, gastric distension, hiatus hernia and increased abdominal pressure can make reflux more likely.
• Refluxed material is not always strongly acidic. It may include food, fluid, pepsin and sometimes bile, and weakly acidic or non-acid reflux can also occur.
• Treatment should look beyond symptom suppression. Meal size and timing, individual triggers, body position, medications and wider digestive function may all need consideration.

What Is Acid Reflux?

Acid reflux, or gastro-oesophageal reflux, occurs when stomach contents flow backwards from the stomach into the oesophagus.

A small amount of reflux can occur normally, particularly after eating. The digestive system has several mechanisms for limiting these episodes and quickly clearing refluxed material from the oesophagus. Problems arise when reflux occurs too frequently, persists for too long or causes troublesome symptoms or damage.

The most familiar symptoms are heartburn and regurgitation. Heartburn is the burning sensation commonly felt behind the breastbone, while regurgitation is the sensation of stomach contents moving upwards towards the throat or mouth.

Acid reflux and GERD: are they the same thing? Not quite.

Gastro-oesophageal reflux (GER) describes the movement of gastric contents into the oesophagus. It can occur occasionally even in healthy people.

Gastro-oesophageal reflux disease (GERD) is the term used when reflux causes troublesome symptoms, complications or both.

This distinction matters because having occasional reflux does not necessarily mean that someone has reflux disease. The aim is therefore not to prevent every reflux event. It is to understand when normal physiology has become a persistent problem and, importantly, why.

The Anti-Reflux Barrier: Why the LES Matters

Between the oesophagus and stomach sits the lower oesophageal sphincter (LES), a specialised ring of muscle that plays a central role in preventing stomach contents from travelling backwards. The LES is not simply a valve that remains tightly closed all the time. It relaxes when we swallow so that food can enter the stomach and then normally regains enough pressure to help prevent gastric contents from moving upwards.

It can also relax temporarily at other times. These transient lower oesophageal sphincter relaxations (TLESRs) are a normal physiological process and allow gas to escape from the stomach, for example when we belch. However, they are also one of the main mechanisms through which reflux occurs.

The diaphragm is part of the barrier too

The LES does not work alone. The oesophagus passes through an opening in the diaphragm called the oesophageal hiatus. The diaphragm muscle surrounding this opening helps reinforce the LES, acting like an additional external sphincter and contributing to the pressure barrier between the stomach and oesophagus. Together, the LES and diaphragm form an important anti-reflux barrier.

This relationship helps explain why a hiatus hernia, where part of the stomach moves upwards through the diaphragmatic opening, can increase the likelihood of reflux. The normal alignment between the LES and diaphragm becomes disrupted, weakening the barrier that helps keep stomach contents where they belong.

Reflux is a balance of pressures

Whether stomach contents remain in the stomach also depends on the pressure on either side of this barrier. The anti-reflux barrier needs to resist pressure generated within the stomach and abdomen. After a large meal, for example, the stomach becomes more distended and intragastric pressure rises. If the barrier temporarily relaxes or cannot adequately resist that pressure, gastric contents are more likely to move upwards.

This gives us a useful way to think about reflux: It is not only about acid. It is also about the barrier, pressure and direction of movement.

The Reflux Sequence

Stomach contents → pressure against the anti-reflux barrier → temporary or persistent failure of the barrier → gastric contents move upwards → oesophageal exposure → possible irritation and symptoms

The question therefore becomes much more useful than simply asking, “Do I have too much stomach acid?” Why are stomach contents moving upwards when they should remain in the stomach?

Why Does Acid Reflux Happen?

Reflux usually does not have one single cause. It develops when the normal mechanisms that keep stomach contents in the stomach are temporarily overwhelmed or persistently impaired. Several factors can contribute, and more than one may be present at the same time.

1. Changes in the anti-reflux barrier

As we have seen, reflux can occur during transient relaxation of the LES, while reduced LES pressure or a hiatus hernia can further compromise the anti-reflux barrier. Importantly, reflux does not necessarily mean the sphincter is permanently “weak”. A normally functioning LES can relax at the wrong time, while structural or pressure-related factors can make reflux more likely when it does.

A hiatus hernia can further weaken the anti-reflux barrier by disrupting the normal relationship between the LES and diaphragm. The important point is that reflux does not necessarily mean the sphincter is permanently “weak”. A normally functioning LES can relax at the wrong time, while structural or pressure-related factors can make reflux more likely when it does.

2. Gastric distension and pressure

What happens inside the stomach matters too. After eating, the stomach expands to accommodate food. Larger meals produce greater gastric distension, and this can increase the likelihood of transient LES relaxations and reflux.

This helps explain why someone may tolerate a particular food in a smaller quantity but experience reflux after a large meal containing the same food. It also shifts the focus away from food alone. Sometimes the question is not simply:

“What did I eat?” but also: “How much did I eat, how quickly, and under what circumstances?”

3. Delayed gastric emptying

Normally, partially digested food gradually leaves the stomach and enters the duodenum.

If gastric emptying is delayed, the stomach may remain fuller for longer. In some people this can contribute to distension and increase the opportunity for reflux, particularly after meals. This illustrates an important systems principle: a problem with movement further down the digestive tract can affect pressure and symptoms further up.

This is one reason reflux should not always be viewed as an isolated oesophageal problem.

4. Increased pressure from the abdomen

Abdominal obesity is an established risk factor for GERD. Increased intra-abdominal pressure can increase the pressure gradient between the stomach and oesophagus, making it easier for gastric contents to move upwards when the anti-reflux barrier is challenged.

Pregnancy can produce a similar mechanical effect as the uterus enlarges, while hormonal changes during pregnancy can also influence oesophageal sphincter function. Other situations that substantially increase abdominal pressure may aggravate symptoms in susceptible people.

Greater pressure from below places greater demands on the anti-reflux barrier above.

5. Meal timing, food and lifestyle

Eating close to bedtime can also be problematic. Lying down removes the assistance of gravity in keeping gastric contents in the stomach and can reduce the effectiveness of oesophageal clearance if reflux occurs.

Individual foods and drinks can aggravate symptoms in some people, but there is no single universal “reflux diet”. Alcohol, chocolate, coffee or caffeine, peppermint, spicy foods, acidic foods and higher-fat meals are frequently reported as triggers. However, responses vary considerably between individuals, and avoiding every commonly listed food can result in an unnecessarily restrictive diet.

Higher-fat meals deserve particular nuance. Dietary fat is not inherently unhealthy or something that everyone with reflux needs to avoid. Large, rich or high-fat meals may worsen symptoms in susceptible people, potentially through effects on gastric distension, emptying and reflux physiology. The more useful approach is to identify repeatable personal patterns rather than assume that every food appearing on a reflux list must be eliminated.

6. Medications and other contributors

Some medications can influence reflux by affecting LES pressure, gastric emptying or the tissues of the oesophagus. Others may directly irritate the oesophageal lining. Examples can include certain calcium-channel blockers, nitrates, anticholinergic medicines and some medications that affect gastrointestinal motility.

This does not mean these medications should be stopped because someone develops reflux. It means medication history is another piece of the clinical picture and may be worth reviewing with the prescribing practitioner. Smoking is also associated with reflux and can impair several protective mechanisms, including LES function and oesophageal clearance.

As with low stomach acid, the useful question is therefore not simply: “What can I take to stop the symptom?” but: “What combination of factors may be allowing reflux to occur?”

Is Reflux Really Caused by Too Much Stomach Acid?

Not necessarily. The burning associated with acid reflux occurs because acidic stomach contents reach the oesophagus, where repeated exposure can irritate and damage tissues that do not have the same protective mechanisms as the stomach.

But experiencing acid reflux does not, by itself, tell us how much acid the stomach is producing. This is an important distinction between acid production and acid exposure. Someone can produce a normal physiological amount of stomach acid but still experience excessive oesophageal acid exposure if the anti-reflux barrier is not functioning effectively or gastric contents are repeatedly moving upwards.

True excessive gastric acid production, or acid hypersecretion, can occur in particular medical conditions, but it is not necessary for reflux to occur.

What about low stomach acid and reflux?

Low stomach acid can also be part of the clinical picture in people experiencing reflux, although the relationship is more complex than simply saying “low stomach acid causes reflux.”

Gastric acidity interacts with digestive signalling, protein digestion, gastric function and the wider digestive process. When digestion is impaired, changes in gastric contents, distension, emptying or signalling may potentially influence reflux symptoms. Symptoms alone cannot tell us whether stomach acid production is high, normal or low. This is why understanding the wider digestive picture matters. This is why understanding the wider digestive picture matters.

If you would like to explore this relationship in more detail, see our guide to Low Stomach Acid: Symptoms, Causes and Natural Support.

Reflux Isn’t Always Just Acid

The term acid reflux can make it sound as though hydrochloric acid is the only substance moving into the oesophagus. In reality, refluxed material can contain a mixture of gastric contents. Depending on what is happening in the digestive tract, this may include:

• Stomach acid
• Partially digested food and fluid
• Pepsin, the protein-digesting enzyme active in the stomach, and
• In some circumstances, duodenal contents including bile.

This matters because oesophageal irritation is influenced not only by whether reflux occurs, but also by what is being refluxed, how often it happens and how long the oesophagus remains exposed.

Acid, weakly acidic and non-acid reflux

Reflux episodes can be classified according to the acidity of the material entering the oesophagus. Some episodes are strongly acidic, while others are weakly acidic or non-acidic. This is particularly relevant in people taking acid-suppressing medication. The medication may substantially reduce the acidity of gastric contents, but it does not necessarily prevent the physical event of reflux itself.

In other words: Reducing acidity can make refluxed material less acidic without necessarily stopping it from moving upwards.

This distinction helps explain why some people continue to experience regurgitation or other symptoms despite effective acid suppression. It also reinforces the central principle of this article. Reflux is not simply a question of how much hydrochloric acid the stomach contains. It involves the movement of digestive contents across the anti-reflux barrier and the exposure of tissues that normally should not encounter them repeatedly.

Common Symptoms of Acid Reflux

The two most characteristic symptoms of reflux are heartburn and regurgitation.

Heartburn is usually experienced as a burning sensation behind the breastbone that may rise towards the throat. It commonly occurs after eating and may worsen when lying down or bending over.

Regurgitation is the sensation of stomach contents or fluid travelling upwards into the oesophagus, throat or mouth. Some people notice a sour or bitter taste.

Other symptoms can include:

• Upper abdominal or chest discomfort
• Nausea
• Excessive belching
• Difficulty or discomfort when swallowing
• Disturbed sleep when reflux occurs at night

Reflux may also be considered in people experiencing symptoms such as chronic cough, hoarseness or throat clearing. However, these symptoms have many possible causes and should not automatically be attributed to reflux. Chest pain also deserves particular caution. Reflux can cause chest discomfort, but new, severe or unexplained chest pain should not simply be assumed to be digestive in origin.

How Is Acid Reflux Assessed?

For many people with typical heartburn or regurgitation, assessment begins with the pattern of symptoms, medical history, medications and contributing factors. Further investigation may be needed when symptoms are persistent, unusual, do not respond as expected to treatment or are accompanied by red flags.

Upper endoscopy

An upper gastrointestinal endoscopy allows the oesophagus, stomach and upper duodenum to be examined directly. It can identify complications such as oesophagitis, narrowing of the oesophagus and Barrett’s oesophagus, as well as help investigate other possible causes of symptoms.

However, an important point is:A normal endoscopy does not necessarily rule out reflux disease. Many people with reflux symptoms do not have visible damage to the oesophageal lining.

Reflux testing

When symptoms persist or the diagnosis is unclear, specialised testing can measure how often stomach contents move into the oesophagus and how much acid exposure occurs over a period of time. Some tests can also detect reflux that is weakly acidic or non-acidic. These investigations are generally used when there is a clinical reason for them rather than being necessary for everyone experiencing occasional reflux.

Supporting Healthy Reflux Control

Once we understand reflux as a problem involving movement, pressure and the anti-reflux barrier, many practical strategies begin to make more sense. The aim is not simply to reduce stomach acid. It is to reduce the conditions that allow gastric contents to reflux into the oesophagus, while identifying and addressing relevant underlying contributors.

1. Consider meal size as well as food choice

Large meals distend the stomach and increase the pressure the anti-reflux barrier needs to contain. If reflux regularly follows large meals, reducing meal size may be more useful than immediately eliminating a long list of foods.

Eating more slowly and chewing food thoroughly can also help avoid overwhelming the stomach with a large volume of food in a short period. Before asking “Which food caused my reflux?”, also consider how much you ate and how quickly.

2. Allow enough time between dinner and bed

Reflux is often more troublesome when we lie down soon after eating because gravity is no longer helping keep stomach contents where they belong. Where possible, finish the evening meal at least 2–3 hours before lying down or going to bed.

For people experiencing troublesome night-time reflux, sleeping position and elevating the upper body may also help. These strategies are particularly relevant when symptoms occur predominantly at night.

3. Identify your triggers rather than following a universal reflux diet

There is no single list of foods that everyone with reflux needs to avoid. If alcohol, coffee, chocolate, peppermint, spicy foods, acidic foods or particularly rich meals consistently reproduce symptoms for you, that pattern is useful information.

But unnecessarily removing every commonly listed reflux trigger can make the diet restrictive without addressing the actual mechanism. Look for repeatable patterns, ideally changing one thing at a time so you can see what genuinely makes a difference.

4. Reduce unnecessary pressure on the stomach

Where relevant, reducing excessive abdominal pressure can substantially improve reflux. For people carrying excess abdominal weight, even moderate weight reduction can improve symptoms. Avoiding very tight clothing around the abdomen may also be helpful for some people.

Body position matters too. Repeated bending or strenuous activity immediately after a large meal can increase pressure against a recently filled stomach. The principle is straightforward: Give the stomach enough room and time to do its job.

5. Look beyond the oesophagus

Persistent reflux deserves a wider digestive perspective. Consider what may be happening upstream and downstream: gastric function and emptying, meal patterns, medication use, hiatus hernia and other digestive symptoms may all provide useful clues.

This is particularly important when reflux occurs alongside bloating, excessive fullness, belching or nutrient deficiencies. Reflux should therefore not automatically be viewed as an isolated oesophageal problem.

For the wider picture, see our foundational guide to gut health and the microbiome.

When Is Acid-Suppressing Medication Appropriate?

Acid-suppressing medications, particularly proton pump inhibitors (PPIs), are effective treatments for many people with GERD. By substantially reducing gastric acidity, they make refluxed stomach contents less acidic and allow inflamed or damaged oesophageal tissue an opportunity to heal.

They can be particularly important in conditions such as erosive oesophagitis and in people at increased risk of reflux-related complications. However, reducing gastric acidity does not necessarily stop the physical event of reflux. Gastric contents may still move upwards, but the material reaching the oesophagus is less acidic and therefore generally less damaging.

This distinction helps explain why some people continue to experience symptoms such as regurgitation despite effective acid suppression.

What about long-term use?

For some people, long-term acid suppression is medically appropriate and provides important protection. For others, treatment may have been started for short-term symptoms and simply continued without the original need being reconsidered. Because stomach acid has normal roles in digestion, nutrient availability and microbial defence, long-term treatment should have a clear clinical reason and be reviewed periodically where appropriate.

If reflux symptoms return when medication is reduced or stopped, this does not automatically mean the medication was unnecessary or that the body is simply “dependent” on it. Rebound acid hypersecretion can occur after prolonged acid suppression and may temporarily increase upper-digestive symptoms.

Prescribed acid-suppressing medication should therefore not be stopped or substantially changed without discussing the reason for treatment and an appropriate management plan with the prescribing practitioner.

When Reflux Needs Medical Investigation

Occasional reflux is quite common, but persistent or changing symptoms should not automatically be managed as simple heartburn. Seek medical assessment if reflux is frequent, worsening, not responding as expected to treatment, or accompanied by symptoms such as:

• Difficulty or pain when swallowing
• Food feeling as though it is sticking
• Unexplained weight loss
• Persistent vomiting
• Vomiting blood or passing black stools
• Unexplained iron-deficiency anaemia
• Persistent or severe upper-abdominal pain.

New, severe or unexplained chest pain also requires appropriate assessment, particularly when accompanied by breathlessness, sweating, dizziness or pain spreading to the arm, jaw or back.

Long-standing reflux can sometimes damage the oesophageal lining and contribute to complications including oesophagitis, narrowing of the oesophagus and Barrett’s oesophagus. This does not mean that everyone with reflux will develop these problems, but it is one reason persistent symptoms deserve appropriate investigation rather than indefinite self-treatment.

Frequently Asked Questions

Conclusion: Look Beyond the Acid

Acid reflux is often approached as a problem of excess stomach acid, but the digestive picture is more complex.

Healthy reflux control depends on the anti-reflux barrier, appropriate pressure within the stomach and abdomen, gastric emptying, meal patterns and the wider digestive process. Stomach acid itself has important physiological roles. The problem arises when gastric contents repeatedly travel in the wrong direction and expose the oesophagus to substances it is not designed to tolerate.

Rather than asking only “How can I reduce the acid?”, a more useful question may be: “Why is reflux happening in the first place?”

Understanding the contributing factors allows us to address the foundations, investigate where necessary and use targeted treatment more appropriately. As throughout the digestive journey, the goal is to help the right substances remain in the right place, at the right time. Explore our Gut Health & Microbiome Knowledge Hub for more insights.

Continue Your Digestive Health Journey

Our digestive health article series continues in the third article: Stomach Acid: Why It Matters for Digestion and Health, where we discuss stomach acid’s importance for digestion, nutrient absorption and microbial defence.

The digestive health article series includes:

• Article #1: Your Digestive System: Following the Journey of Food Through the Gut
• Article #2 – Acid Reflux: Why It Happens and What You Can Do About it – You are here
• Article #3 – Stomach Acid: Why It Matters for Digestion and Health (coming soon)

Next Steps

Ready to Put This Into Practice?

The Digestive Health Guide & Workbook takes the next step, helping you identify your own digestive patterns, strengthen the foundations of healthy digestion and decide where to begin. It includes practical tools, self-checks, a 14-Day Digestive Foundations Reset and simple food-based recipes.

If you’re unsure how this applies to your health, personalised support can help clarify the next step. I offer online consultations Australia-wide where we look at sleep, gut health, hormones, and metabolic function as an integrated system.

Book Consultation Online

Learn about our wholistic, systems approach to care in The Naturimedica Way and about Online Consultations.

I look forward to supporting you in achieving greater balance, energy and wellbeing.

Best of Health

Joanna Sochan
Wholistic Health and Lifestyle Therapist
Integrative health support combining clinical evidence, systems-based thinking and traditional naturopathic wisdom for lasting health and wellbeing

References and Sources

Where applicable, content is informed by peer-reviewed research, clinical literature, and traditional naturopathic practice knowledge.

1. Katz PO, Dunbar KB, Schnoll-Sussman FH, et al. ACG Clinical Guideline for the Diagnosis and Management of Gastroesophageal Reflux Disease. American Journal of Gastroenterology. 2022;117(1):27–56.
PubMed: ACG GERD Clinical Guideline

2. Yadlapati R, Gyawali CP, Pandolfino JE, et al. AGA Clinical Practice Update on the Personalized Approach to the Evaluation and Management of GERD: Expert Review. Clinical Gastroenterology and Hepatology. 2022;20(5):984–994.e1.
PubMed: AGA Personalized GERD Review

3. Kahrilas PJ, et al. The relevance of transient lower oesophageal sphincter relaxations in the pathophysiology and treatment of GORD.
Full-text review: TLESRs and reflux physiology

4. Emerenziani S, et al. Obesity & GERD. Gastroenterology Clinics of North America. 2014.
Full-text review: Obesity and GERD

5. Borbély Y, et al. Excess Body Weight and Gastroesophageal Reflux Disease. Visceral Medicine. 2021;37:267–272.
Full article: Body Weight and GERD

6. Gyawali CP, et al. / contemporary review. Refractory Gastroesophageal Reflux Disease: Diagnosis and Management.
PubMed: Refractory GERD Diagnosis and Management

7. Muthusamy VR, et al. / AGA. AGA Clinical Practice Update on the Diagnosis and Management of Extraesophageal Gastroesophageal Reflux Disease: Expert Review. 2023.
PubMed: Extraoesophageal GERD Review

8. Yadlapati R, et al. AGA Clinical Practice Update on De-Prescribing of Proton Pump Inhibitors: Expert Review. 2022.
PubMed: PPI Deprescribing Guidance

9. Namikawa K, Björnsson ES. Rebound Acid Hypersecretion after Withdrawal of Long-Term Proton Pump Inhibitor Treatment: Are PPIs Addictive? International Journal of Molecular Sciences. 2024;25(10):5459.
PubMed: Rebound Acid Hypersecretion Review

10. Lødrup AB, Reimer C, Bytzer P. Systematic review: symptoms of rebound acid hypersecretion following proton pump inhibitor treatment. Scandinavian Journal of Gastroenterology. 2013;48(5):515–522.
PubMed: Systematic Review of Rebound Acid Hypersecretion

Disclaimer: This content is for informational and educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any changes to your health regimen, particularly if you are taking prescription or over-the-counter medications or have a medical condition.

Bio: Joanna Sochan is a Wholistic Natural Therapist and founder of Naturimedica Wholistic Wellcare. She has over 15 years of clinical experience working with complex health presentations, with a focus on gut health, food sensitivities, women’s hormone health (including perimenopause and menopause), metabolic health, weight regulation, and senior health. She works with clients Australia-wide and online, and also develops therapeutic programs, eCourses, and educational resources designed to support long-term, sustainable wellbeing. View full bio.