A comprehensive study of European adults has found that compared with people who drink a single sugar-sweetened drink daily, those who drink water, coffee or tea instead are at 14% lower risk of developing type 2 diabetes.
The research found that drinking sugar-sweetened milk products was an even more powerful driver of diabetes; compared with those who drank one such beverage daily, people who drank water, coffee or tea instead were on average 20% to 25% less likely to develop diabetes.
The British study, which tracked the consumption habits of more than 25,000 Britons (ages 40 to 79) over about 11 years, offered little comfort to drinkers of artificially sweetened beverages. While consumers of coffee, tea and water had a diminished risk of diabetes, the study found consumers of diet sodas to have type 2 diabetes risks on par with drinkers of sugar-sweetened beverages.
But when the authors took body mass index and waist circumference into account, they found that consumption of diet beverages was not linked to higher rates of diabetes. This suggests that diet soda drinkers are already more likely to be overweight or obese, and that this - rather than their diet soda consumption - might account for their elevated diabetes risk.
The new research, published in Diabetologia, the journal of the European Assn. for the Study of Diabetes, offered another surprise as well: consumption of fruit juice and sweetened tea or coffee was not associated with diabetes.
While offering some insights into different beverages' contribution to diabetes rates, the study does not test the likely effects of changing established consumption patterns and substituting one kind of drink for another. Instead, it tracked the consumption patterns of a large population over a lengthy period of time to see who was more or less likely to develop diabetes.
Such a "prospective observational study" does not establish that sugar-sweetened sodas directly cause diabetes, or that, say, a longstanding consumer of sugary sodas can lower her diabetes risk by switching to tea. As a "prospective observational study," it may be finding, for instance, that more health-conscious people - those already at lower risk of diabetes - from the start are simply more likely to choose coffee, tea or water over chocolate milk, sweetened beverages or diet soda.
But it does give some sense of scale to what the authors call the "population impact of sweet beverage consumption on type 2 diabetes": in a large population, each 5% increase of average total daily calorie intake provided by sweetened drinks appears to boost new cases of type 2 diabetes by 18%. And if people's average daily calorie intake from sweetened beverages were below 10%, 5% or 2% of their total daily calories, 3%, 7% or 15% respectively of new-onset diabetes cases could be avoided, the authors concluded.
Public health experts recommend that a typical adult diet - with an intake of about 2,000 calories a day - should include no more than 130 calories from added sugar. A single 12-ounce can of Coca Cola Classic, with 140 calories, will exceed that recommendation. Chocolate milk contains on average 60 calories worth of added sugar per serving.