Consuming diet fizzy drinks every day almost triples the risk of developing dementia, a major new study suggests.

People who regularly drank artificially sweetened beverages are also more likely to suffer a stroke, but the full-fat equivalent is not associated with a greater risk of either condition.

Researchers have warned, however, not to treat sugary drinks as a healthy option, saying there may be an as yet undetected link between full-fat drinks, dementia and stroke.

The nature of the study means they cannot prove a causal link between diet drinks and dementia, but previous research has shown that artificial sweeteners can damage blood vessels.

Scientists at the University of Boston assessed the dietary habits of more than 4,000 people for seven years, and then monitored their health for a further decade.

They found that people who drank at least one artificially-sweetened beverage a day were 2.9 times more likely to develop Alzheimer’s disease and three times as likely to suffer an ischemic stroke than those who barely drank any.

In the UK, people have roughly a 7 per cent chance of developing dementia between the age of 65 and 80, with the odds increasing to more than 16 per cent above that age.