Have you experienced a burning sensation in your chest after a big meal and wondered what’s causing it? Or perhaps you often regurgitate or have trouble swallowing food leaving a sour taste in your mouth?
These may all be symptoms of acid reflux, also referred to as gastro-oesophageal reflux, which is when the acidic contents of your stomach travel back up to your throat. It is normal to experience acid reflux from time to time, but you might want to consult with a medical professional if it happens too often. Recurring acid reflux is referred to as Gastro-Oesophageal Reflux Disease (GORD) and might lead to other serious diseases if left untreated.
What is acid reflux?
Acid reflux is a phenomenon affecting digestive health and is described as the backwash of stomach contents up into the oesophagus, irritating its lining and causing a burning sensation in the chest called heartburn. The food and drink we consume travels to the stomach via the oesophagus, a muscular tube connecting our throat to the stomach. The muscles in our oesophagus contract and push the chewed-up food down towards the stomach for digestion.
The stomach maintains a very acidic environment to effectively digest and further break down the chewed-up food. Our stomachs are lined with cells which help maintain this acidic environment (by releasing gastric acid and enzymes) whilst also protecting the organ itself from the acidic stomach content (by secreting mucus).
Unlike the stomach, the cells lining the oesophagus are incapable of protecting themselves from highly acidic contents. Hence, with acid reflux, the oesophagus may become irritated and inflamed, causing heartburn and disrupting digestive health.
Long-term chronic acid reflux is referred to as Gastro-Oesophageal Reflux Disease (GORD), where prolonged exposure of the oesophagus to stomach acid may cause chronic irritation and inflammation. According to the National Center for Biotechnology Information (NCBI), only 1 out of 3 people with reflux symptoms develop an inflamed oesophagus.1
A chronically inflamed oesophagus, however, may lead to further complications such as Barrett’s oesophagus, where the cells lining the oesophagus heal abnormally and undergo metaplasia (where cells of one type begin to change and are eventually replaced by another cell type, which in this case, is intestinal cells). These changes are precancerous and may lead to oesophageal cancer if left untreated. Other related conditions include oesophagitis ( oesophageal inflammation) and oesophageal stricture (an abnormal narrowing of the oesophagus).
Causes of acid reflux
Acid reflux is primarily caused by the malfunction of the lower oesophageal sphincter (LES), which is a ring-shaped muscle that acts as a valve between the oesophagus and the stomach.2
The LES should maintain a one-way direction, relaxing to allow food to enter the stomach but otherwise remains closed.
Several factors can contribute to the malfunction of the LES:
- Transient lower oesophageal sphincter relaxations (TLERs): Short moments of LES relaxation which occur independent of swallowing.3 Although usually harmless, they occur a lot more often in the period after a meal and may be a major cause of acid reflux
- Decreased LES pressure: Causing the LES to relax
- Hiatal hernias: When part of the stomach moves up to the chest, creating abdominal pressure
- Impaired oesophageal clearance: The oesophagus does have mechanisms to remove acid but these can be impaired
- Delayed gastric emptying (gastroparesis): Movement of the stomach muscles is slowed down or stops
Signs and symptoms of acid reflux
The most common symptom of acid reflux is heartburn. Despite what the name suggests, heartburn is not associated with problems with the heart. It is described as a painful, burning chest pain radiating toward the mouth caused by an irritation to the lining of the oesophagus.
Another common symptom is a lingering sour taste at the back of the throat and the regurgitation of stomach contents. This may also be accompanied by bad breath, a hoarse voice, a cough or hiccup that keeps coming back, difficulty swallowing, and also the feeling of nausea or bloating. All these symptoms can occur at any time but are often worse after meals or when in a reclined/lying down position.
Reflux disease can typically be diagnosed by symptom presentation, so make sure to include as many details as you can when consulting a health professional including what your symptoms are, their frequency, and if you have certain ‘trigger’ foods.
Acid reflux risk factors
Acid reflux is known to affect people of differing ages and backgrounds, sometimes with no determined reason. Although lots of acid reflux risk factors are lifestyle-related, not all forms of this reflux disease are preventable.
Food-related risk factors are typically associated with symptoms of acid reflux:
- Diet: Acidic foods, spicy food, or fatty foods along with carbonated, alcoholic, and caffeinated drinks are often labelled as ‘trigger foods’ as they are more likely to cause acid reflux
- Eating big meals: The stomach stretches after a big meal to accommodate for the large intake of food, which may temporarily loosen the LES
- Eating too close to sleep: It typically takes up to 3 hours for our stomach to fully empty. Staying upright allows gravity to ensure our stomach content stays down. Lying down straight after a meal may cause leakage of stomach acid and heartburn
Some other common risk factors include:
- Smoking or regular exposure to secondhand smoke: Nicotine relaxes certain muscles in the body, including the LES, opening the passageway between the stomach and oesophagus
- Pregnancy: As the uterus grows, it presses on the stomach. Certain hormones during pregnancy can also slow down the digestion process (including the closing of the oesophageal sphincters). Both these factors can contribute to TLERs, acid indigestion, and backwash
- Obesity: Increased abdominal pressure and impaired gastric emptying contribute to TLERs
- Certain medication: Non-Steroidal Anti-inflammatory Drugs (NSAIDs) such as Ibuprofen, Aspirin, and Naproxen may trigger heartburn by increasing acid production and damaging the protective layer of the stomach
- Stress and anxiety: Emotional stress may stimulate gastric acid production and decrease the production of prostaglandins, hormones involved in protecting the stomach lining from acid
Management and treatment for acid reflux
There are many methods to manage and treat acid reflux symptoms, varying from lifestyle changes, to over-the-counter (OTC) medication, to even prescribed medication and surgical interventions.
The first-line in reflux disease treatment will typically gear towards lifestyle modifications, including limiting smoking, large evening meals, nighttime snacking, ‘trigger’ foods and alcohol consumption. Maintaining a healthy weight and healthy eating and sleeping schedule can also help. Sleeping with your head and chest above your stomach has been proven to decrease oesophageal acid exposure - this is referred to as head of the bed (HOB) elevation.2
Medications such as antacids (neutralise stomach acid), and alginates (physical barrier to prevent backwash) are available over the counter and aid in symptom management. Prescription medication is another treatment option if modifications to your lifestyle don't improve your symptoms:
Proton pump inhibitors (PPI)
Proton pump inhibitors are considered to be the most effective medical therapy for chronic acid reflux.4 They suppress acid production by inhibiting an enzyme (a type of protein which speeds up reactions in the body) called hydrogen-potassium ATPase located in the lining of the stomach. This enzyme is involved in the final step of acid production and blocking it will decrease the release of gastric acid into the stomach. The most common types of PPIs prescribed for GERD symptoms are Omeprazole, tablets sold under the brand names Losec and Prilosec, and Lansoprazole, sold under brand names Zoton FasTabs and Prevacid.
H2 Receptor antagonists (H2RAs)
H2 receptor antagonists also decrease gastric acid production.5 They do this by blocking histamine H2 receptors on the lining of the stomach, preventing histamine from binding to to the receptor. After a meal, histamine is usually released to initiate several steps in producing stomach acid, so blocking its receptor will decrease gastric acid production.5 Nizatidine and Famotidine are both oral tablets prescribed for GERD.
If after a while prescription medication still doesn’t have the desired effect of symptom relief, fundoplication (anti-reflux surgery) is a last resort treatment option.6 It involves wrapping a section of the stomach around the oesophagus to prevent backflow of its acidic content, but, as with any other surgery, carries its own risks.
How common is acid reflux?
Up to 20% of individuals in Western countries develop symptoms of acid reflux such as heartburn and regurgitation from time to time, especially after a large meal.1 This doesn’t typically become a health problem unless the symptoms occur regularly or are severe.
How is acid reflux diagnosed?
A doctor can perform an upper endoscopy (gastroscopy) using a long thin tube with a little camera attached to one end (endoscope) to visualise the inside of your oesophagus and check for narrowing, inflammation, or other abnormalities. Alternatively, an oesophageal pH test can also be utilised to measure the amount of acid reflux over a 24-hour period.
Can acid reflux be prevented?
Although there isn’t a guaranteed way of preventing acid reflux, there are some precautions you can take to lower your chances of developing GERD. Not eating too much and too close to sleep (3 hours) is a general rule to allow proper digestion and prevent acid regurgitation. Limiting your consumption of ‘trigger’ foods known to cause acid reflux such as fatty food, spicy food, acidic food, and alcohol, and reducing smoking may also help prevent GERD symptoms.
What does acid reflux feel like?
The most common acid reflux symptom is heartburn, a burning sensation causing chest pain and sometimes upper abdominal pain as well. This is usually exacerbated after big meals or during night time and may be accompanied by a bitter, acidic taste in your mouth or bad breath.
When should I call a doctor?
You should reach out to your primary care doctor if you develop acid reflux symptoms (or take OTC medication for these symptoms) over twice a week or when symptoms are severe.
Acid reflux is the backwash of acidic stomach content into your oesophagus, irritating it and causing heartburn. Often this is normal, but you should seek medical advice if your symptoms are severe or frequent as this could be an indication of chronic acid reflux or gastro-oesophageal reflux disease (GERD), a prerequisite to other serious diseases such as Barrett’s oesophagus and oesophageal cancer. What and when you eat, along with other lifestyle factors are considered to be major risk factors in acid reflux disease. Symptoms can be managed by implementing lifestyle modifications, OTC medication, prescribed medication, or in some cases, surgery.
- Heartburn and gerd: overview [Internet]. Institute for Quality and Efficiency in Health Care (IQWiG); 2018 [cited 2023 Mar 1]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279254/
- Clarrett DM, Hachem C. Gastroesophageal reflux disease(Gerd). Mo Med [Internet]. 2018 [cited 2023 Mar 6];115(3):214–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6140167/
- Kim HI, Hong SJ, Han JP, Seo JY, Hwang KH, Maeng HJ, et al. Specific movement of esophagus during transient lower esophageal sphincter relaxation in gastroesophageal reflux disease. J Neurogastroenterol Motil [Internet]. 2013 Jul 31 [cited 2023 Mar 6];19(3):332–7. Available from: http://www.jnmjournal.org/journal/view.html?doi=10.5056/jnm.2013.19.3.332
- Sandhu DS, Fass R. Current trends in the management of gastroesophageal reflux disease. Gut and Liver [Internet]. 2018 Jan 15 [cited 2023 Mar 9];12(1):7–16. Available from: https://www.gutnliver.org/journal/view.html?doi=10.5009/gnl16615
- Nugent CC, Falkson SR, Terrell JM. H2 blockers. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 [cited 2023 Mar 9]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK525994/
- Heartburn and gerd: treatment options for gerd [Internet]. Institute for Quality and Efficiency in Health Care (IQWiG); 2018 [cited 2023 Mar 11]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279252/