For many years it was thought that peptic ulcers (gastric ulcers or duodenal ulcers) were caused by stress, poor dietary habits (including eating too much rich, fatty or spicy foods), alcohol, caffeine and smoking. It was believed that these factors contributed to the build-up of stomach acids that eroded the protective lining of the stomach and duodenum. Because of this all the treatment at the time was directed at neutralizing and inhibiting the stomach’s acid secretion.

Helicobacter pylori infection.

However, research has now shown that although excessive stomach acid and lifestyle factors certainly do play a part in the development of ulcers, most ulcers occur as a result of infection by a bacterium known as Helicobacter pylori ( H. pylori ), a corkscrew-shaped organism which lives in the inner lining of the stomach. H. pylori was discovered by  researchers in a huge breakthrough which revolutionized the treatment of ulcers worldwide. H. pylori infection is very common. Most adults in developing countries are infected. Infection rates are less for Western countries—about 40 per cent of people over the age of 40 are thought to have it, and 10 per cent of children.

How is H. pylori infection acquired?

Although doctors are not certain, they suspect the bacteria may be spread through sharing food, cutlery and utensils for eating and drinking with infected people. H. pylori has been detected in the saliva of infected people, leading scientists to think that it may also be spread by mouth-to-mouth contact, such as kissing. Most people with the infection do not develop ulcers, although after being infected many people may suffer an attack of gastritis, which is an inflammation of the stomach lining.

Those who carry this bacteria today have most probably been infected during childhood. The risk of acquiring infection for an adult is modest - less than 1 per cent every year. Helicobacter pylori in itself does not usually cause any ulcer symptoms. Nevertheless, this bacteria is the most common cause of ulcers in the stomach and the duodenum.

The bacteria may also have a role in the development of cancer of the stomach. Helicobacter pylori infection can be eliminated by taking antibiotics. There is about an 80 per cent chance of successful treatment of the infection and a cure for the ulcer.

If the bacteria is not eliminated, most people get a recurrence of their ulcer after a short period of time. The infection is usually acquired in childhood. However, older adults who were children in the 1920s through to the 1940s are much more likely to be infected than the young children and adolescents of today.

Why some people with H. pylori infection develop ulcers where others who are also infected do not is not entirely clear. However, whether an infected person develops an ulcer or not may depend on their personal characteristics, or environmental or hereditary factors. Researchers are continuing to investigate this question.

How does H. pylori cause ulcers?

H. pylori bacteria can penetrate the stomach’s protective lining of mucus and can live there. It can do this because it produces an enzyme called urease. Urease produces neutralizing agents which protect the H. pylori from the strong acid of the stomach.

The protective lining of the stomach and duodenum and the mucus the stomach secretes are there to protect them from the digestive juices of the stomach. When H. pylori is living in the stomach or duodenum, it can sometimes interfere with this protective mechanism and allow the acid to attack the protective lining. This causes breaks in the lining, leaving it open to erosion by the powerful digestive juices.