Background: The effects of the regular intake of beverages containing high-intensity sweeteners on insulin sensitivity in healthy individuals remain controversial.

Objective: This trial compared the effects of the consumption of a carbonated beverage containing aspartame and acesulfame K (high-intensity sweeteners beverage-HISB) with those of an unsweetened, no-calorie carbonated beverage (UB) on insulin sensitivity and secretion in nondiabetic adults.

Methods: SEDULC was a randomized, double-blind, crossover study. Nondiabetic adults [mean age 31 y, 44% men, body mass index (BMI; kg/m²) 19-29] who did not consume high-intensity sweeteners were randomized 1:1 to drink 1 of the 2 carbonated beverages, 2 cans (330 mL each)/d, for 12 wk. After a 4-wk washout period, participants were switched to the opposite beverage for 12 wk. The primary outcome tested was the change in insulin sensitivity as assessed by the Matsuda Insulin Sensitivity Index (MISI) after an oral glucose load. Secondary outcomes were indexes of insulin secretion.

Results: Sixty individuals were enrolled and 50 completed the study (28 nonoverweight and 22 overweight participants). The change in MISI from baseline did not significantly differ between beverages and noninferiority was demonstrated (difference = -0.23; 95% CI: -1.31, 0.85; P < 0.0001). The change in insulinogenic (means ± SEMs: 0.23 ± 0.14 for HISB compared with 0.08 ± 0.1 for UB) and disposition indexes (2.70 ± 0.99 for HISB compared with 1.62 ± 0.90 for UB) did not differ, and no differences in insulin secretion estimates were confirmed by the Stumvoll indexes. Consuming the high-intensity sweeteners did not affect body weight, self-reported dietary consumption, or self-reported physical activity.

Conclusions: These findings suggest that the daily consumption of 2 cans of a beverage containing aspartame and acesulfame K over 12 wk has no significant effect on insulin sensitivity and secretion in nondiabetic adults. This trial was registered at clinicaltrials.gov as NCT02031497.