The global study of more than 450,000 adults in 10 countries – including the UK – found that daily consumption of all types of soft drinks was linked with a higher chance of dying young.

But the rates for those drinking artificially-sweetened beverages were significantly higher than those consuming full sugar versions, the WHO research found.

The experts said consumers were better off sticking with water.

The research, which tracked participants for an average of 16 years, is the largest study to examine links between soft drink consumption and mortality.

The new research found death rates among those consuming at least two diet drinks a day were 26 per cent higher than among those who had less than one month.

This group also saw their chance of being killed by cardiovascular disease rise by 52 per cent.

The findings suggest Government policies aimed at cutting sugar consumption – such as the sugar tax on fizzy drinks, and “reformulation” of common sweet foods – could have disastrous consequences.

Mortality rates were also higher among those regularly drinking sugary drinks.

But overall, they were only eight per cent more among those drinking two such drinks a day, compared with those having less than one month.

The findings were published in JAMA Internal Medicine.

Experts said it was possible that people drinking diet drinks were doing so because they were obese or had diseases such as diabetes, but said the study had tried to adjust for that.

Professor Mitchell Elkind, incoming president of the American Heart Association, said “other studies have suggested biological mechanisms may include an impact on insulin signalling in the liver.

The study, led by the International Agency for Research on Cancer, part of WHO, was observational – meaning it did not prove that the drinking habits caused the higher death risks.

Researchers said there was some evidence suggesting that artificial sweeteners could induce glucose intolerance and spikes in insulin levels.

And they said more research was needed to explore the possible adverse effects of additives, such as aspartame.

They also said it was possible that those who were drinking high amounts of diet drinks had been unhealthy and overweight at the start of the study, and switched from previously drinking high sugar versions.

But the study, published in Jama Internal Medicine, found the link between artificially sweetened soft drinks and higher mortality persisted when the analysis was limited to those of healthy weight. In the study, one glass was equivalent to about 250 ml – less than a standard 330ml can sold in the UK.

Lead author Dr Neil Murphy said the findings were “striking” and the third large study this year to find a link between diet drinks and raised mortality rates.

“It would probably be prudent to limit consumption of all soft drinks and replace with a healthier alternative, such as water,” he said.

Gavin Partington, director general at British Soft Drinks Association, said: “Soft drinks are safe to consume as part of a balanced diet.

“According to all leading health authorities in the world, as well as Cancer Research UK and Diabetes UK, low- and no-calorie sweeteners are safe.”

Culled from www.telegraph.co.uk