Residual gastric volume after 3 h of the ingestion of an oral supplement containing carbohydrates alone or associated with whey protein: a randomized crossover pilot study

BACKGROUND: New formulas including a nitrogenous source to maltodextrin have been reported as preoperative beverages 2–3 h before anesthesia in the elective procedure. Whey protein is a potential candidate for the composition of this clear oral supplement. This study aimed to investigate the gastric residual volume (GRV) of healthy volunteers 3 h after the ingestion of an oral supplement containing carbohydrates (CHO) alone or combined with whey protein (WP). METHODS: This crossover clinical trial design includes young, healthy male volunteers with normal body mass index. Magnetic resonance imaging (MRI) scan of the upper abdomen to measure the GRV was performed in the participants in three phases: (1) after a fasting period of 8 h; (2) immediately after the ingestion of 200 mL of a clear supplement containing: (2a) 10 g of WP and 54 g of CHO (74% glucose and 26% maltodextrin)–WP + CHO group or (2b) 12.5% maltodextrin (25 g)–CHO group; and (3) after 3 h of the ingestion of both types of supplements. A week interval was programmed between phases 2a and 2b. RESULTS: There was no significant difference (p = 0.91; within-group comparison) of the mean ± SD of the GRV between phase 1 (WP + CHO: 23.45 ± 14.01; CHO: 25.03 ± 15.17 cm(3); p = 0.78; between-groups comparison) and phase 3 (WP + CHO: 25.66 ± 9.31; CHO: 23.45 ± 13.58 cm(3), p = 0.86; between-groups comparison). The GRV of phase 2 (WP + CHO: 206.43 ± 23; CHO: 203.99 ± 12.18 cm(3); p = 0.82; between-groups comparison) was significantly greater (p < 0.01; within-group comparison) than both other two phases. CONCLUSION: The GRV after 3 h of the ingestion of either WP + CHO or CHO oral supplement returns to basal fast condition implying that gastric emptying after this interval of time is significantly completed. TRIAL REGISTRATION: Registered and posted on the ClinicalTrials.gov public website with Identifier: NCT05573854.