Common causes

The symptoms of reflux disease may vary but there is one main cause and it is mechanical, not chemical.

Reflux disease is caused by the failure of a valve known as the lower oesophageal sphincter. When working correctly, this valve allows food and liquid to pass into the stomach, but prevents the contents of the stomach refluxing up into the oesophagus. With reflux disease this weakened value allows harmful acid and bile to flow back into the oesophagus.

In this section: Causes explained

In many cases there is no identifiable reason why the condition develops. Anything that contributes to the valve failure is likely to cause increased symptoms, such as:

  • Hiatus hernia

    The diaphragm is a large flat muscle that separates the chest and abdominal cavities. Normally the oesophagus passes through a hole in the diaphragm from the chest into the abdomen where the stomach is located. This hole is called the hiatus. A hiatus hernia develops when this hole enlarges and the usual connections between the diaphragm and the oesophagus break down. In time, this allows the upper part of the stomach to push through or herniate up into the chest. The valve mechanism at the bottom of the oesophagus may then be caused to fail. However, it is important to realise that many people will develop reflux without a hiatus hernia and others may have a hiatus hernia but experience no reflux.

  • Obesity

    There is a link between high Body Mass Index (BMI) and reflux. As fat builds up within the abdomen extra pressure is put on the stomach and the LOS. Additionally, a diet high in fat may exacerbate reflux symptoms.

  • Pregnancy

    This is partly because of hormonal changes and is also partly due to the increased pressure within in the abdomen caused by the growing baby.

  • Smoking

    It is generally thought that the nicotine in tobacco relaxes the muscle of the lower oesophagus, worsening reflux. Additionally, smoking can cause the mouth to produce less saliva, which some people can find exacerbates their symptoms.

  • Stress

    It has been found that people who are stressed or anxious report higher levels of pain or discomfort due to reflux symptoms. There is debate surrounding whether stress physically worsens the condition or whether when stress causes a person’s awareness of pain to be heightened. Whatever the reason, stress can worsen reflux discomfort.

  • Delayed stomach emptying

    Delayed stomach emptying, (gastroparesis) is a condition where a partial paralysis of the stomach can cause it to fail to empty properly, and so food stays in the stomach longer than is usual. It is common in people who have diabetes, as high blood sugar levels may damage the nerves that control the stomach.