Carbohydrates (CHO)-based drinks 2h before the induction of anesthesia are recommended to decrease insulin resistance. The addition of glutamine (GLN) in these beverages may enhance the benefits of CHO alone. However, only a few studies tested the safety of this formula. The objective of this study was to evaluate the gastric residual volume (GRV) after the intake of a beverage containing CHO plus GLN using magnetic resonance (MRI).

We included 11 male young volunteers (aged between 21 and 30 years-old) with body mass index (BMI) between 20 and 29 kg/m2 and without either acute or chronic illness in the last 3 months. The criteria for exclusion were non-adherence to any phase of the study protocol, gastroesophageal reflux disease, previous history of intolerance to lactose, gastroparesis or history of poor gastric emptying, diabetes mellitus, and previous abdominal surgery.

Each volunteer was randomized for participation in the study in a blind fashion. All subjects underwent two different protocols before MRI with an interval of seven days between them. Both phases took place after an overnight fast of eight hours. The volunteers ingested 400ml (4 hours before the exam was carried out) at 8:00AM and 200ml (2 hours before the exam was carried out) at 10:00AM of a beverage containing either water plus 12.5% maltodextrin (Phloraceae, Cuiabá, Brazil; CHO group) or the same beverage plus 15g of GLN (Phloraceae, Cuiabá, Brazil; GLN group). The participants were instructed not to ingest alcohol, medication, and caffeine within 24 hours of the study, nor do any vigorous physical activity during that time.

In both phases the individuals were blind to the specific drink and they were told to ingest the beverage in a maximum period of five minutes and T0 was defined as the moment they complete the intake of the solution.The powdered products (maltodextrin alone or maltodextrine plus glutamine) were packed in coded opaque sachets and the content was only known by the pharmacist who manipulated it.

All the participants in the study underwent magnetic resonance of the upper abdomen at 12:00AM and 01:00PM. The GRV observed during the first exam was defined as T120 and the second exam as T180. All exams were performed by the same magnetic resonance equipment (Intera 1.5T ; Philips Healthcare, Eindhoven, Holland).

Inclusion Criteria:

• Young male volunteers (aged between 21 and 30 years-old) with body mass index (BMI) between 20 and 29 kg/m2 and without either acute or chronic illness in the last 3 months.

Exclusion Criteria:

• non-adherence to any phase of the study protocol,
• gastroesophageal reflux disease,
• previous history of intolerance to lactose,
• gastroparesis or history of poor gastric emptying,
• diabetes mellitus, and
• previous abdominal surgery