Diet Sodas, as Well as Regular Ones, Raise Diabetes Risk

Miriam E. Tucker

February 14, 2013

A new study from France suggests that women who drink large amounts of diet soda are at increased risk for type 2 diabetes. The findings also support the previously documented association between high intake of regular sugar-sweetened beverages and the condition, report Guy Fagherazzi, from the Center for Research in Epidemiology and Population Health, Villejuif, France, and colleagues in a study published online January 30 in the American Journal of Clinical Nutrition.

Prior research into the relationship between diet soda (artificially sweetened beverages) and type 2 diabetes has produced conflicting results, and while the current study does not necessarily imply causation, there are some biologically plausible mechanisms, the researchers suggest.

And given that diet sodas are "considered — and marketed — as healthier than sugar-sweetened beverages," the findings require further investigation, they say. In the meantime, the authors advise that "a precautionary principle could be applied to the promotion of [artificially sweetened beverages]."

Highest Intake of Diet Soda More Than Doubles Diabetes Risk

The data come from a large prospective cohort study of 66,118 women in France investigating links between diet and cancer. There were 1369 new cases of type 2 diabetes diagnosed during the follow-up period from 1993 to 2007.

Based on self-reported dietary consumption, the average intake of regular sodas was 328 mL/week, while for diet sodas it was higher, at 568 mL/week.

The risk for type 2 diabetes was elevated among the women in the highest quartiles for both sugar-sweetened beverages (>359 mL/week) and artificially sweetened beverages (>603 mL/week) compared with women who did not consume those beverages, with hazard ratios of 1.34 and 2.21, respectively, after multivariate adjustment for a variety of covariates (other than body mass index [BMI]).

Strong positive trends in type 2 diabetes risk were observed across quartiles of consumption for both types of beverage (P = .0088 and P < .0001, respectively). Adjustment for BMI did modify the results somewhat, although the associations remained significant for both sugar-sweetened beverages and artificially sweetened beverages.

The authors also conducted sensitivity analyses to test the hypothesis that people who are at risk for type 2 diabetes by virtue of obesity may preferentially drink artificially sweetened beverages, but the results suggest that such a "reverse causation" mechanism is "unlikely," they note.

"Our results — in accordance with a recent joint scientific statement of the AHA and ADA — strongly suggest the need to conduct randomized trials that evaluate metabolic consequences of [artificially sweetened beverage] components, such as artificial sweeteners, to prove a causal link between [artificially sweetened beverage] consumption and type 2 diabetes," the study authors conclude.

The authors have disclosed no relevant financial relationships.

Am J Clin Nutr . Published online January 30, 2013. Abstract