The Digestive System

This is made up of the gastrointestinal tract, also called the alimentary canal. It consists of the oesophagus, stomach, the small intestine (duodenum, jejunum and ileum) and the colon (caecum, ascending, transverse, descending and sigmoid colon and the rectum). Food passes from the mouth through the gastrointestinal tract where is processed and absorption of nutrients takes place in the small intestine. The undigested food is processed in the colon to stool and passed out through the anus.


  • Food is chewed in the mouth and mixed with saliva to eventually form a bolus which is propelled to the back of the mouth by the tongue.

  • Initiation of the swallow takes place with the bolus pushed down into the oesophagus through the upper oesophageal sphincter.

  • Coordinated oesophageal muscle contractions (peristalsis) moves the bolus from the upper oesophageal sphincter through the length of the oesophagus to the lower oesophageal sphincter (LES).
  • The LES relaxes to allow the bolus to enter the stomach where further digestion takes place.

  • In the stomach the food mixes with stomach acid and other digestive enzymes.
  • The LES prevents digested food, stomach acid and digestive enzymes from moving back up into the oesophagus.


  • GERD is a condition that develops when reflux of stomach contents causes troublesome symptoms and/or complications.
  • The stomach acid and digestive enzymes can be very irritating and even damaging to the lining of the oesophagus.
  • The oesophagus can initially protect itself from damage by its own muscular contractions called tertiary peristalsis. Tertiary peristalsis propels the partially digested food and fluids back into the stomach.
  • Damage to the oesophageal lining as a result of GERD can over many years lead to changes in the lining of the oesophagus – called Barrett’s oesophagus. This condition has a slight increased risk of cancer of the oesophagus. Your gastroenterologist will discuss this with you if applicable.


    A number of contributing factors have been identified and some people may have a combination of them.
    • Poorly functioning LES: caused/aggravated by
      1. Certain medications
      2. Certain foods and beverages
    • Slow emptying of the stomach
    • Poor tertiary contractions
    • Too much stomach acid
    • Fragile oesophageal lining
    • Hiatus hernia (see picture)
    • Increased intra-abdominal pressure like in pregnancy
    • Heartburn – a burning sensation in the upper abdomen and chest related to meals. This is the commonest symptom.
    • Dyspepsia – upper abdominal pain/discomfort.
    • Regurgitation – a feeling that food is coming back into the mouth
    • Acid or bitter taste in the mouth
    • Difficulty swallowing
    • Nausea, infrequent vomiting (acid)
    • Asthma like symptoms – cough and wheeze
    • Hoarse voice, sore throat
    • Tooth decay, bad breath and gum problems


    If your primary care doctor feels that an investigation is needed, a gastroscopy is the investigation of choice for GERD. During this procedure, a thin, flexible tube with a small camera at the tip, linked to a light source is passed down from the mouth into the oesophagus and then into the stomach and duodenum (see picture below). It also allows for biopsy (minute samples) specimens to be taken from abnormal areas during the procedure. It helps to diagnose/exclude more serious conditions at the same time.

    A gastroscopy is mandatory in the following setting:
    • When vomiting blood
    • Weight loss
    • Anaemia – suggesting you are losing blood slowly.
    A barium meal/swallow is performed for anatomical delineation and especially if swallowing difficulty is experienced.

    Oesophageal pH monitoring is performed in selected cases where symptoms are difficult to control or are persistent in spite of treatment. Your gastroenterologist will suggest this when necessary. The procedure involves the placement of a thin catheter in the oesophagus recording oesophageal acid exposure over a prolonged period.


    • In uncomplicated GERD, proton pump inhibitor (PPI) therapy is the treatment of choice. PPI therapy must be taken ±30minutes before breakfast. In rare cases, your gastroenterologist may advise twice daily dosing.
    • This is usually done in conjunction with life-style modification. See below on ‘self-help’ section.
    • Your gastroenterologist will also review your current medication and discontinue medication that may aggravate GERD.
    • In very rare instances, surgery may be indicated. Discuss with your doctor the pros and cons of surgery.


     Lifestyle changes are useful in GERD and include the following:
    • Avoid large fatty meals
    • Decrease meal portions
    • Avoid food types that you directly associate with aggravation of your symptoms.

    • Follow a regular exercise routine
    • Avoid alcohol and tobacco
    • Try to lose weight if overweight
    • Avoid tight fitting clothes
    • Avoid eating 2-3 hours before bed-time
    • Elevate the head end of bed – place a brick on the floor under the head end of the bed.