Widespread sucralose exposure in a randomized clinical trial in healthy young adults

Background: Low-calorie sweeteners (LCSs) are found in many foods and beverages, but consumers may not realize their presence, and their role in appetite, weight, and health is controversial. Although consumption limits based on toxicologic safety are well established, the threshold required to exert clinically relevant metabolic effects is unknown.Objectives: This study aimed to determine whether individuals who do not report consumption of LCSs can be correctly characterized as "unexposed" and to investigate whether instructions to avoid LCSs are effective in minimizing exposure.Design: Eighteen healthy 18- to 35-y-old "nonconsumers" (<1 food or beverage with LCSs/mo) enrolled in a 2-wk trial designed to evaluate the effects of LCSs on the gut microbiota. The trial consisted of 3 visits. At baseline, participants were counseled extensively about avoiding LCSs. After the run-in, participants were randomly assigned to consume diet soda containing sucralose or carbonated water (control) 3 times/d for 1 wk. Food diaries were maintained throughout the study, and a spot urine sample was collected at each visit.Results: At baseline, 8 participants had sucralose in their urine (29.9-239.0 ng/mL; mean ± SD: 111.4 ± 91.5 ng/mL). After the run-in, sucralose was found in 8 individuals (2 of whom did not have detectable sucralose at baseline) and ranged from 25.0 to 1062.0 ng/mL (mean ± SD: 191.7 ± 354.2 ng/mL). Only 1 participant reported consumption of an LCS-containing food before her visit. After the intervention, sucralose was detected in 3 individuals randomly assigned to receive carbonated water (26-121 ng/mL; mean ± SD: 60.7 ± 52.4 ng/mL).Conclusions: Despite the selection of healthy volunteers with minimal reported LCS consumption, more than one-third were exposed to sucralose at baseline and/or before randomization, and nearly half were exposed after assignment to the control. This shows that instructions to avoid LCSs are not effective and that nondietary sources (e.g., personal care products) may be important contributors to overall exposure. This trial was registered at clinicaltrials.gov as NCT02877186.