Causes of Heartburn
The causes of heartburn are wide-ranging and often interconnected, involving dietary habits, lifestyle choices, medical conditions, and anatomical abnormalities. At its core, heartburn results from the backward flow of stomach acid into the oesophagus. A process known as acid reflux. This reflux irritates the sensitive lining of the oesophagus, leading to the familiar burning sensation in the chest or throat. Understanding the causes of heartburn is essential to managing symptoms effectively and preventing long-term complications.
One of the most frequent causes is the relaxation or weakening of the lower oesophageal sphincter (LES). The LES is a circular band of muscle at the junction between the oesophagus and the stomach. It acts like a valve, opening to allow food into the stomach and closing to keep stomach contents from rising. When this valve becomes dysfunctional—either due to pressure changes or muscle weakness. It may allow acid and partially digested food to travel upwards, resulting in reflux and heartburn.
Dietary Triggers
Dietary triggers are among the most common and well-documented contributors to heartburn. Foods that are high in fat, particularly fried or greasy dishes, tend to delay gastric emptying. Which increases pressure in the stomach and promotes reflux. Spicy foods, acidic ingredients like tomatoes and citrus fruits. Furthermore, certain condiments such as vinegar or mustard can all irritate the oesophagus directly or stimulate excess acid production.
In addition to spicy or acidic meals, caffeine and alcohol are known to relax the LES. Making it easier for acid to escape the stomach. Caffeinated drinks—such as coffee, energy drinks, and strong tea—can exacerbate symptoms in susceptible individuals. Similarly, alcohol not only weakens the LES but also stimulates acid production, creating a double effect. Chocolate and peppermint are two less obvious culprits; while often considered indulgent or soothing, both have muscle-relaxing properties that affect the LES.
Causes of Heartburn
Eating habits and meal timing also play a significant role in the development of heartburn. Large meals stretch the stomach, increasing internal pressure and the likelihood of acid escaping into the oesophagus. Eating just before lying down or going to bed is especially problematic, as it removes the advantage of gravity in keeping acid in the stomach. This is why heartburn often worsens at night or when reclining after a meal.
Another major factor is obesity. Excess weight, particularly around the abdomen, increases intra-abdominal pressure, pushing the stomach upward and reducing the strength of the LES. This mechanical pressure not only increases the frequency of reflux episodes but can also make them more severe. Studies consistently show a higher prevalence of heartburn and gastro-oesophageal reflux disease (GORD) in individuals who are overweight or obese.
Pregnancy
Pregnancy is a common cause of temporary heartburn due to hormonal and mechanical changes. The hormone progesterone, which increases during pregnancy, relaxes smooth muscle throughout the body—including the LES. At the same time, the growing uterus places pressure on the stomach, making reflux more likely. Most pregnant women experience some level of heartburn, particularly during the second and third trimesters.
Certain medications can also contribute to heartburn. These include non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and aspirin, which can irritate the stomach lining and promote acid production. Other common offenders include calcium channel blockers (used for high blood pressure), sedatives, certain antidepressants, and medications for asthma. In some cases, even supplements like iron or potassium can worsen symptoms if taken without adequate fluid or food.
Smoking is another major lifestyle factor that contributes to heartburn. Nicotine reduces LES pressure and interferes with saliva production, which normally helps neutralise stomach acid. Smokers are also more likely to experience prolonged acid exposure in the oesophagus, increasing the risk of complications like oesophagitis or Barrett’s oesophagus.
Causes of Heartburn
Hiatus hernia is an anatomical condition in which part of the stomach pushes through the diaphragm and into the chest cavity. This can impair the function of the LES and increase the likelihood of acid reflux. While not everyone with a hiatus hernia experiences heartburn, the condition is a well-established risk factor and often contributes to more severe or treatment-resistant symptoms.
Delayed gastric emptying, or gastroparesis, is another medical condition that can lead to heartburn. When the stomach empties too slowly, it increases pressure and volume within the stomach, raising the risk of acid reflux. This is often seen in people with diabetes, especially those with nerve damage affecting the gastrointestinal tract.
Stress & Anxiety
Stress and anxiety are often overlooked but play a subtle role in triggering or worsening heartburn. While they may not directly cause acid reflux. They can increase stomach acid production, reduce LES tone, and amplify perception of pain. People under chronic stress may also adopt poor eating habits. Such as eating too quickly, overeating, or choosing unhealthy foods—which further contribute to symptoms.
The causes of heartburn can also be influenced by age. As people grow older, natural changes in the oesophageal lining and sphincter muscle make reflux more likely. Ageing is also associated with reduced saliva production and slower digestion, both of which can exacerbate symptoms.
In many cases, heartburn is multifactorial—meaning it results from a combination of the above factors rather than a single cause. For example, a person who is overweight, smokes, and frequently eats large meals late at night will likely experience more severe and frequent episodes than someone with only one of those risk factors.
Causes of Heartburn
In summary, the causes of heartburn encompass a mix of lifestyle habits, dietary choices, physiological changes, and medical conditions. Identifying personal triggers and understanding the mechanisms behind them is the first step in developing an effective prevention and treatment strategy. While occasional heartburn is usually not serious, frequent or severe symptoms should prompt further medical evaluation to rule out underlying disorders and reduce the risk of complications.
