Gastroesophageal reflux disease (GERD), or acid reflux, occurs when your stomach acid rises up into your oesophagus and throat. You might notice a sudden bout of heartburn – a burning sensation in the centre of your chest. If so, you might have acid reflux. 

But what causes acid reflux? We often focus on the symptoms and how to treat the condition. However, understanding the causes and triggers of acid reflux can help combat any painful episodes. Read on to learn more.

What Causes Acid Reflux? 

Acid reflux refers to the movement of stomach acid into the oesophagus, throat, and even mouth. Usually, the lower oesophageal sphincter (LOS) – a ring of muscle separating the stomach and oesophagus – acts as the barrier, preventing backflow. However, if the LOS is opened, the acid can backflow.  

So, what causes acid reflux? Well, there tend to be two mechanisms: 

• There's an increase in acid production. Certain foods, medications, or lifestyle habits trigger stomach acid production. When reflux occurs without high levels of acid, you may not even notice. But as the pH level drops, your heartburn increases.

• The LOS relaxes and becomes looser. Like any sphincter, the LOS must maintain its muscle tone to function. If it relaxes or is overcome by the pressure in your stomach, then the stomach contents can easily backflow into the oesophagus. Some substances naturally relax the LOS, while other habits increase your stomach pressure. 

Remember, each person is different. You might have a reasonably strong LOS. However, your stomach acid production is so high that whatever backflow occurs will cause serious discomfort. Understanding your underlying physiology is crucial to solving the problem. 

What Triggers Acid Reflux? 

What causes acid reflux is only half the battle. Unfortunately, life doesn't easily separate these items into either category. Often, triggers will cause a combination of both – increasing stomach acid and relaxing the LOS. 

Acid reflux triggers fall into a few categories: 

Diet 

Your diet is the primary factor affecting your acid reflux. Eating certain foods can increase acid production and relax your LOS. These foods include: 

• Spicy, fatty, or greasy foods

• Acidic fruits and vegetables, such as tomatoes, onions, and citrus fruits

• Coffee and other sources of caffeine, including chocolate

• Alcohol

• Carbonated drinks

• Peppermint or spearmint 

Your portion size is also important. Large portions increase your stomach pressure, forcing the LOS to open. When combined with acid-triggering foods, it can lead to severe acidity attacks.  

Medications 

People are often surprised to learn that their medications are behind their acid reflux symptoms. Certain medications can cause noticeable episodes of acid reflux. Look out for: NSAIDs (e.g., ibuprofen, aspirin)  

• Calcium Channel Blockers (e.g., amlodipine) 

• Anticholinergics (e.g., oxybutynin) 

• Bisphosphonates (e.g., alendronate) 

• Certain Antibiotics (e.g., tetracycline) 

• Iron Supplements 

• Potassium Supplements  

• Progesterone  

Some Antidepressants (e.g., amitriptyline, SSRIs) Your doctor should always explain the potential side effects before starting the medication. If you notice any changes, speak to your doctor for further details.  

Smoking 

Smoking can aggravate the respiratory system and boost the production of stomach acid. Specifically, nicotine weakens the muscles of the LOS, aggravating symptoms of reflux and heartburn.  

Research from 2016 indicated that adults who gave up smoking experienced a 44% decrease in acid reflux symptoms over a year, in stark contrast to a mere 18.2% reduction in those who did not quit smoking. 

Stomach Pressure 

Stomach pressure covers several acid reflux triggers. Pregnancy is the most obvious factor in increasing your stomach's pressure. As the baby grows, your uterus expands, pressing against the stomach and forcing the LOS to open. 

Rising levels of progesterone and oestrogen can also relax the LOS, allowing it to open more easily. As a result, pregnant women often complain of frequent acid reflux attacks. 

The other factor increasing stomach pressure is obesity. The more weight you have, the greater your stomach pressure. Combined with the fact that people who are overweight or obese usually eat a diet high in fat, a known trigger for acid reflux, it's not hard to see why reflux would be such a problem here. 

Hiatus Hernia 

A hiatus hernia occurs when a portion of the stomach pushes up through the diaphragm into the chest cavity. This displacement disrupts the diaphragm's role in supporting the LOS, leading to the unimpeded backflow of stomach acids and food into the oesophagus. 

People notice that their symptoms get worse when bending over or lying down. It's often treated surgically – but your doctor will need to perform a full evaluation to determine the extent of the issue. 

Getting Tested for Acid Reflux  

Does this sound familiar? If so, you might have acid reflux. Here at The Functional Gut Clinic, we offer comprehensive testing, including 24-hour reflux monitoring and oesophageal manometry to assess your LOS’s function. Our experienced team will explain your results thoroughly and guide you on the next steps. Confirm your GERD symptoms with our expert help. Contact us today for more information.