Diet soda linked to increase in glucagon-like peptide 1 levels

(HealthDay) -- Drinking a diet soda before a glucose load is associated with increased glucagon-like peptide 1 (GLP-1) secretion in individuals with type 1 diabetes and healthy controls, but not in those with type 2 diabetes, according to research published online March 12 in Diabetes Care.

Rebecca J. Brown, M.D., M.H.S.C., of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Md., and colleagues conducted a randomized, crossover study involving nine individuals with type 1 diabetes, 10 with type 2 diabetes, and 25 healthy controls, aged 12 to 25 years. Participants drank either a cola-flavored, caffeine-free diet soda or carbonated water, followed by a 75-gram glucose load. They then underwent glucose, C-peptide, GLP-1, glucose-dependent insulinotropic peptide, and peptide Tyr-Tyr measurements for 180 minutes.

Compared with carbonated water, the researchers found that, after ingestion of diet soda, the GLP-1 area under the curve was 34 percent higher in healthy subjects and 43 percent higher in individuals with type 1 diabetes (P = 0.029 and 0.020, respectively), but was unaffected in subjects with type 2 diabetes. None of the other gut hormone measures were significantly statistically different between the groups after ingestion of diet soda or carbonated water.

"It is unknown whether changes in endogenous GLP-1 secretion as observed in the current study have any clinically relevant consequences, such as increased satiety and slowed gastric emptying," the authors write.