Addition of an alginate hydrogel to a carbohydrate beverage enhances gastric emptying

Purpose This study aimed to examine the effect of altering osmolality or adding sodium alginate and pectin to a concentrated carbohydrate (CHO) beverage on gastric-emptying (GE) rate. Methods Boluses (500 mL) of three drinks were instilled double blind in eight healthy men while seated, GE was measured using the double sampling method for 90 min, and blood samples were collected regularly. Drinks consisted of glucose and fructose (MON; 1392 mOsmol·kg-1), maltodextrin and fructose (POLY; 727 mOsmol·kg-1), and maltodextrin, fructose, sodium alginate, and pectin (ENCAP; 732 mOsmol·kg-1) with each providing 180 g·L-1 CHO (CHO ratio of 1:0.7 maltodextrin or glucose/fructose). Results Time to empty half of the ingested bolus was faster for ENCAP (21 ± 9 min) than for POLY (37 ± 8 min); both were faster than MON (51 ± 15 min). There were main effects for time and drink in addition to an interaction effect for the volume of test drink remaining in the stomach over the 90 min period, but there were no differences between MON and POLY at any time point. ENCAP had a smaller volume of the test drink in the stomach than MON at 30 min (193 ± 62 vs 323 ± 54 mL), which remained less up to 60 min (93 ± 37 vs 210 ± 88 mL). There was a smaller volume of the drink remaining in the stomach in ENCAP compared with POLY 20 min (242 ± 73 vs 318 ± 47 mL) and 30 min (193 ± 62 vs 304 ± 40 mL) after ingestion. Although there was a main effect of time, there was no effect of drink or an interaction effect on serum glucose, insulin or nonesterified fatty acid concentrations. Conclusion The addition of sodium alginate and pectin to a CHO beverage enhances early GE rate but did not affect serum glucose, insulin, or nonesterified fatty acid concentration at rest.