Drinking water in the place of soft drinks or sweetened milk drinks could help to reduce the risk of developing diabetes.
In the study, published in Diabetologia, the researchers find that for every 5% increase in daily energy intake that is provided by sweet drinks, such as soft drinks and artificially sweetened beverages, the risk of type 2 diabetes could increase by up to 18%.
"Our study adds further important evidence to the recommendation from the World Health Organization to limit the intake of free sugars in our diet," states study leader Dr. Nita Forouhi, of the Medical Research Council Epidemiology Unit at the University of Cambridge, UK.
Substantial observational evidence supports an association between the consumption of sugar-sweetened beverages and type 2 diabetes, yet previous research has often relied on the use of food frequency questionnaires. It is difficult for these questionnaires to assess individual beverage types, and many do not account for sugar added by individuals to drinks such as tea and coffee.
"Dietary assessment using prospective food diaries can provide the detailed data that overcomes such limitations but this method has not been widely used in epidemiological research," the study authors write.
For the study, the researchers recorded the beverage consumption of 25,639 adults in the UK participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) Norfolk Study. Participants were 40-79 years old, and none had diabetes at the start of the study.
To measure beverage consumption, the participants recorded everything that they ate and drank for a period of 7 consecutive days. Specific attention was paid to the types of beverages consumed by the participants, the amounts and frequencies by which they were consumed and whether they added any sugar to their drinks.
"By using this detailed dietary assessment with a food diary, we were able to study several different types of sugary beverages as well as artificially sweetened beverages - such as diet soft drinks - and fruit juice, and to examine what would happen if water, unsweetened tea or coffee or artificially sweetened beverages were substituted for sugary drinks," explains Dr. Forouhi.
The participants were followed up for approximately 11 years after completing the dietary assessments. During this time, 847 of the participants were diagnosed with new-onset type 2 diabetes.
Risk of diabetes increased by up to 22% with daily consumption of some beverages
For each extra daily serving of soft drinks, sweetened milk beverages and artificially sweetened beverages consumed, the researchers found that the risk of type 2 diabetes increased by approximately 22%. Consumption of fruit juice and sweetened tea or coffee was not associated with the risk of diabetes.
After adjusting their findings for body mass index (BMI) and waist girth, the authors also found that the link between diabetes and artificially sweetened beverages no longer remained. The authors believe this may be because these drinks are consumed more frequently by people who are already overweight.
Additionally, the researchers calculated the extent by which the risk of diabetes would decrease if certain drinks were replaced with water or unsweetened tea or coffee. Drinking one of these instead of a daily serving of soft drinks was found to reduce the risk by 14% and replacing a daily serving of sweetened milk beverage reduced the risk by 20-25%.
Unfortunately, the researchers also found that replacing a sugar-sweetened drink with an artificially sweetened drink was not associated with any significant reduction in the risk of diabetes.
"The good news is that our study provides evidence that replacing a habitual 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," says Dr. Forouhi.
Their findings were limited, however, by the fact that dietary intake was only measured at the beginning of the study, and as such does not allow for any changes that may have occurred over time. The authors argue that the nationally representative UK adult intakes of sweet beverages are 30% higher than those recorded in the study, suggesting that greater benefits may be possible.
"In light of the consistency of past evidence, together with the new evidence generated by this work, it is now timely and appropriate to consider population-based interventions to reduce [sugar-sweetened beverage] consumption and increase the consumption of suitable alternative beverages," the authors conclude.
Earlier this year, Medical News Today reported a study identifying added fructose as a principal driver of type 2 diabetes.