The study, published in Diabetologia indicates that for each 5% increase of a person’s total energy intake provided by sweet drinks including soft drinks, the risk of developing type 2 diabetes could increase by as much as 18%.
“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,” explained study leader Dr Nita Forouhi, of the Medical Research Council (MRC) Epidemiology Unit, University of Cambridge.
The team found that substituting one serving of soft drinks and sweetened-milk beverages per day with water or unsweetened tea or coffee was associated with between 14% and 25% fall in type 2 diabetes incidence.
Indeed, Forouhi and colleagues suggested that if sweet beverage consumers reduced their intake to below 2% energy then up to 15% diabetes cases might be prevented.
“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,” said Forouhi.
“This adds further important evidence to the recommendation from the World Health Organization to limit the intake of free sugars in our diet.”
The research is based on the EPIC-Norfolk study, which included more than 25,000 men and women aged 40–79 years living in Norfolk, UK. Participants recorded everything that they ate and drank for seven consecutive days covering weekdays and weekend days, with particular attention to type, amount and frequency of consumption, and whether sugar was added by the participants.
During approximately 11 years of follow-up, 847 study participants were diagnosed with new-onset type 2 diabetes.
Analysis by the team, which accounted for a range of factors including total energy intake, found that there was an approximate 22% increased risk of developing type 2 diabetes per extra serving per day habitually of each of soft drinks, sweetened milk beverages and artificially sweetened beverage consumed - but that consumption of fruit juice and sweetened tea or coffee was not related to diabetes.
After further accounting for body mass index and waist girth as markers of obesity, a higher risk of diabetes associated with consumption of both soft drinks and sweetened milk drinks, remained but the link with artificially sweetened beverages consumption did not, said the team – adding that the initial association is likely explained by their greater consumption by those who were already overweight or obese.
Forouhi and colleagues’ analysis also suggested that if study participants had replaced a habitual daily serving of soft drinks with a serving of water or unsweetened tea or coffee, the risk of diabetes could have been cut by 14% - and by replacing a habitual serving of sweetened milk beverage with water or unsweetened tea or coffee could slash risk by between 20% and 25%.
However, consuming artificially sweetened beverages instead of any sugar-sweetened drink was not associated with a statistically significant reduction in type 2 diabetes, when accounting for baseline obesity and total energy intake, they added.
Published online ahead of print, doi: 10.1007/s00125-015-3572-1
"Prospective associations and population impact of sweet beverage intake and type 2 diabetes, and effects of substitutions with alternative beverages"
Authors: Laura O’Connor, et al