People who suffer frequent bouts of heartburn have a 78 per cent higher risk of throat cancer, new research suggests.

However, the study also revealed that taking antacids has a protective effect – people who suffer from heartburn but take antacids have a 41 per cent lower risk of throat cancer than those who do not take the medication.

Experts, who published their findings in the journal Cancer Epidemiology, Biomarkers and Prevention, studied 631 patients, 468 of whom had throat cancer and 163 cancers of the vocal cord.

All participants completed a questionnaire on their history of heartburn, smoking and drinking habits, and family history of cancer.

Among those who were neither heavy smokers nor heavy drinkers, a history of frequent heartburn was linked to a 78 per cent increased risk for cancers of the throat and vocal cord.

Among those who had frequent heartburn, taking antacids, but not prescription medications or home remedies, had a protective effect, with a 41 per cent reduced risk for cancers of the throat and vocal cord.

Dr Scott Langevin, of Brown University in the U.S., said: ‘Previous studies examining gastric reflux and cancers of the head and neck have generated mixed results.

‘Most of those studies had either few numbers of cases or they were not adjusted for confounding factors.

‘Ours is a large, population-based study with robust parameters that strongly suggests gastric reflux, which causes frequent heartburn, is an independent risk factor for cancers of the pharynx (throat) and larynx (vocal cord).

‘Additional studies are needed to validate the chemo-preventive effects of antacids among patients with frequent heartburn.

‘The identification of gastric reflux as a risk factor for throat and vocal cord cancers, however, may have implications in terms of risk stratification and identification of high-risk patients.’

Heartburn is when acid leaks out of the stomach and splashes up the oesophagus.

Heartburn is not in itself dangerous. After an occasional bout the cells of the oesophagus burned by the acid will simply heal.

However, persistent heartburn can lead to the development of a protective layer of cells, a condition called Barrett’s oesophagus, which affects as many as 375,000 Britons.

The problem is that this protective layer consists of abnormal cells that withstand the acid, but are more likely to become cancerous.

As a result, some of those with Barrett’s — between 5 and 10 per cent of cases — will go on to develop oesophageal cancer.

Catching Barrett’s at the pre-cancerous stage, when it is highly treatable, is vital as the outlook for oesophageal cancer is poor, with only 13 per cent of patients surviving beyond five years. The disease kills 7,000 in Britain every year.

Heartburn is also becoming increasingly common — a recent study suggested the numbers suffering with it has risen by 50 per cent in a decade.

Much of this increase is blamed on rising levels of obesity. Excess weight can put pressure on the valve that closes the top of the stomach, allowing acid to leak out.

However, there are other factors that can increase the risk of heartburn, such as alcohol or over-indulgence.

Certain foods — those high in fat, spice or caffeine — can make it worse because they also relax the valve.

Another, more common cause is hiatus hernia, when part of the stomach pushes up into the chest, putting pressure on the stomach valve.

There are a number of different treatment options for people with severe heartburn.

It can be treated by making lifestyle changes, such as losing weight, stopping smoking and reducing alcohol and caffeine consumption.

Some people require medications, such as antacids, and others need surgery to strengthen the muscle at the bottom of the oesophagus that closes to keep food and acid from coming back up.