The team found those who drank the highest amounts of sugar-sweetened beverages–a median of six 12 fluid ounce servings a week–had a significantly greater risk of developing prediabetes compared to low- or non-consumers, after adjusting for factors such as age, sex and body mass index. The highest consumers of sugar-sweetened beverages had roughly 8 percent higher insulin resistance scores, compared to low- or non-consumers after follow-up at seven years. Even after accounting for change in weight and other aspects of diet, the relationships between sugar-sweetened beverages and these metabolic risk factors for diabetes persisted.
Diet soda intake–defined as low-calorie cola or other carbonated low-calorie beverages–had no statistical associations with risk for either prediabetes or insulin resistance. However, previous research on the relationship between diet soda and type 2 diabetes has been mixed, and it is still unclear whether any observed associations are due to direct or indirect factors. More research is needed to determine whether there are real health risks with long-term diet soda consumption, say the study authors. In addition, the authors caution that despite adjusting for multiple factors, residual confounding cannot be ruled out due to the observational nature of the study. Participants who were analyzed in the study were mostly middle-aged and Caucasian, more likely to be women, and had lower body mass index and waist circumference, which may limit the generalizability of the findings.
A significant body of research has found associations between regular consumption of sugar-sweetened beverages and increased risk of type 2 diabetes. The new findings now provide evidence of an association with the major predictor of type 2 diabetes. If diagnosed early, prediabetes is reversible through lifestyle changes such as diet and exercise.
“Based on our observational study alone, we cannot be certain why we saw the relationships we did. Additional studies are needed to fully understand the health impact of sugar-sweetened beverages and diet sodas,” said lead study author Jiantao Ma, Ph.D., who conducted the analysis as part of his doctoral thesis as a student in the Nutrition Epidemiology Program at the USDA HNRCA and the Friedman School.
“Nevertheless, our data are consistent with many other studies and clinical trials that support the health benefits of reducing sugar intake, and we encourage the public to look for healthier options,” added Ma, who is currently a postdoctoral fellow at the National Heart, Lung, and Blood Institute of the National Institutes of Health.
