Updated 24 June 2014

The real cause of stomach ulcers

The discovery of the bacteria called helicobacter pylori led to great changes in the treatment of peptic ulcers.


Before the discovery of Helicobacter (H.) pylori, it was generally thought that the stomach was a sterile environment. And that peptic ulcers were largely caused by lifestyle choices and circumstances.

Smokers, people from a socio-economically-disadvantaged background and people who led a stressful lifestyle, more commonly suffered from peptic ulcers.

In the 1960s and 1970s, acid-suppressing drugs, such as H2-receptor antagonists and proton pump inhibitors, often managed to cure peptic ulcers without surgery. But they often recurred again, and it was generally thought that that was because of the lifestyle that caused them in the first place.

The discovery of helicobacter pylori

In the early 1980s, two Australian doctors, Warren and Marshall, found a bacterium that lived in the lower half of the stomach. This bacterium had found a way of concealing itself in the stomach lining in such a way, that it could not be attacked and destroyed like other bacteria that found its way into the stomach.

They were unsure whether the bacterial infection caused caused the gastritis or whether the gastritis allowed the infection to flourish. Dr Marshall infected himself with the bacteria, developed gastritis, and then cured himself with a course of antibiotics. This proved that the bacteria caused the gastritis.

This bacteria was always associated with a microscopic inflammation of the stomach lining, called gastritis. This bacteria has since been associated with chronic gastritis, active chronic duodenitis, duodenal ulcers and gastric ulceration. It also strongly linked to stomach cancer.

Initially this bacteria was called Campylobacter Pylori, but was recently renamed Helicobacter pylori. A particularly virulent strain of H.pylori is known as cytotoxin-associated gene A (cag A). This causes damage severe enough to produce precancerous changes.

Infection and lifestyle trigger peptic ulcers

Further research has found that as much as 40 percent of the population have the infection in their stomachs. Many of those remain unaffected, but 10 percent of those harbouring the infection go on to develop peptic ulcers. It is thought that ulcers are triggered in this group by a number of factors, such as chronic stress, genetics, smoking and coffee-drinking.

How does the infection spread?

This infection is most often found in people who live in confined spaces with many others. The infection is present in saliva and is thought to be in faeces too. Obviously, good personal hygiene is important in preventing the spreading of this infection. It is also found more often in people over the age of 65 and the reason for this is thought to be that many of them were infected as a result of living conditions during the Second World War.

The consequences of the infection

Most people harbouring this infection will suffer no ill effects throughout their lives. Ten percent of them, however, will go on to develop peptic ulcers. It is not known exactly what triggers this.

When the infection is present, it causes the stomach to produce more acid and the stomach lining to become thinner, allowing acid to penetrate.

H. pylori infection does not cause heartburn or GORD and in some patients it appears to protect against some of the symptoms of these two conditions. It is not yet fully understood why this happens. It is also not yet clear which role, if any, the infection plays in the development of stomach cancer.

The discovery of these bacteria certainly changed the way doctors treat peptic ulcers. A short course of antibiotics, instead of acid-reducing medication, has become the norm. It should be noted, though, that lifestyle changes are still important in people who have peptic ulcers, as unhealthy habits can trigger peptic ulcers, when the infection is present. It is very easy to become re-infected with H. pylori.


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