Swapping a daily sugary drink for water or unsweetened tea or coffee can lower the risk of diabetes by up to 25%, research has suggested.

A study by the University of Cambridge also found that for every 5% increase of a person's total energy intake provided by sugar-sweetened drinks, the risk of developing type 2 diabetes may increase by 18%.

Researchers analysed a separate large-scale study of more than 25,000 people aged 40 to 79 living in Norfolk who recorded everything they ate and drank. During around 11 years of follow-up, 847 participants were diagnosed with new-onset type 2 diabetes.

The team looked at whether they drank sugar-sweetened beverages (such as fizzy drinks and squashes), sweetened-milk beverages (like milkshakes, flavoured milks and hot chocolate), sweetened tea or coffee, artificially sweetened drinks and fruit juice, and found that nearly all participants consumed at least one sweet beverage, with soft drinks the most commonly consumed.

They found that s oft drinks and sweetened-milk beverages were all associated with a greater incidence of diabetes, but artificially sweetened beverages, sweetened tea or coffee and fruit juice were not.

They estimated that replacing one soft drink or sweetened-milk beverage a day with a serving of water or unsweetened tea or coffee reduced the incidence of diabetes by 14% to 25%.

"Our findings suggest that reducing consumption of sweet beverages, in particular soft drinks and sweetened-milk beverages, and promoting drinking water and unsweetened tea or coffee as alternatives may help curb the escalating diabetes epidemic," the authors concluded.

Analysis of the food diaries led them to find that consumers of sweetened tea or coffee and sweetened-milk beverages were more likely to be from a lower social class and have generally less healthy diets. Fruit juice consumers were of higher social class and had generally healthier diets.

Lead scientist Nita Forouhi, of the UK Medical Research Council (MRC) epidemiology unit at the University of Cambridge, said: "The good news is that our study provides evidence that replacing a daily serving of a sugary soft drink or sugary milk drink with water or unsweetened tea or coffee can help to cut the risk of diabetes, offering practical suggestions for healthy alternative drinks for the prevention of diabetes.

"Our new findings on the potential to reduce the burden of diabetes by reducing the percentage of energy consumed from sweet beverages add further important evidence to the recommendation from the World Health Organisation to limit the intake of free sugars in our diet."

The research, published in Diabetologia (the journal of the European Association for the Study of Diabetes), follows a previous study that showed that habitual daily consumption of sugar-sweetened beverages was linked with higher risk of type 2 diabetes.

It is estimated that at least 3.2 million people in the UK have type 2 diabetes, which is linked to increasing levels of obesity, unhealthy diets and a lack of exercise.