Consumption of beverages containing non-nutritive sweeteners has increased worldwide, but limited information is available regarding the short-term urinary excretion of acesulfame potassium (Ace-K) and the acute metabolic response following consumption of commercially available beverages. This study investigates the urinary pharmacokinetics of Ace-K and the acute urinary metabolomic response after consumption of 500 mL of Coca-Cola Zero Sugar in healthy adults. Participants complete two study arms under free-living conditions: Coca-Cola Zero Sugar and still water (control), separated by a one-month washout period. Urine samples are collected before beverage consumption and repeatedly over the subsequent 24 hours. Proton nuclear magnetic resonance (¹H NMR) spectroscopy is used to quantify Ace-K and other urinary metabolites. The study aims to determine the urinary appearance and elimination kinetics of Ace-K and to identify metabolic changes associated with Coca-Cola Zero Sugar consumption compared with water.

Non-nutritive sweeteners (NNS) are widely used as sugar substitutes in reduced-calorie foods and beverages. Among these, acesulfame potassium (Ace-K) is extensively incorporated into commercially available soft drinks because of its high sweetening potency, thermal stability, and minimal caloric contribution. Following oral ingestion, Ace-K is rapidly absorbed and excreted predominantly unchanged in urine, making it a promising biomarker of NNS consumption and dietary exposure. However, limited information is available regarding the urinary pharmacokinetics of Ace-K following consumption of commercially formulated beverages under free-living conditions.

Proton nuclear magnetic resonance (¹H NMR) spectroscopy enables simultaneous quantitative analysis of exogenous compounds and endogenous metabolites in complex biological samples. By applying the same analytical platform to both the intervention beverage and sequential urine samples, this study investigates the relationship between the ingested dose of Ace-K and its urinary excretion profile while simultaneously evaluating short-term metabolic responses following Coca-Cola Zero Sugar consumption.

This non-randomized, within-subject controlled study compares the urinary metabolomic response after consumption of Coca-Cola Zero Sugar with that observed following consumption of still water. The study aims to characterize the urinary appearance and elimination kinetics of Ace-K, quantify pharmacokinetic parameters including time to peak concentration and urinary elimination half-life, and explore acute changes in urinary metabolite profiles associated with Coca-Cola Zero Sugar consumption using quantitative ¹H NMR metabolomics.

Inclusion Criteria:

• Healthy adults aged 18 to 60 years
• Able and willing to provide written informed consent
• Willing to consume 500 mL of Coca-Cola Zero Sugar and 500 mL of still water during separate study periods
• Willing to collect urine samples before and during the 24 hours after each intervention according to the study instructions
• Willing to avoid foods and beverages containing non-nutritive sweeteners for 48 hours before each study period

Exclusion Criteria:

• Younger than 18 years or older than 60 years
• Current smoker
• Known kidney disease or metabolic disease
• Regular use of prescription medications
• Use of antibiotics in last 3 months
• Consumption of foods or beverages containing non-nutritive sweeteners within 48 hours before either study period
• Unable or unwilling to comply with the study procedures or urine collection schedule

Individual participant data will not be made publicly available. De-identified data may be considered for sharing upon reasonable request to the study investigators, subject to institutional policies, ethical approval, and applicable data protection regulations.