Increased Fluid Delivery from Drinks with Multiple Transportable Carbohydrates

Abstract

Recent results from our laboratory have shown that exogenous carbohydrate use can be increased when a beverage multiple transportable carbohydrates is ingested compared to a single carbohydrate only. Since fluid is partly absorbed as a result of solvent drag, we hypothesized that these drinks may also enhance fluid delivery. Deuterium appearance in the body's water stores was used as an indicator of fluid delivery. PURPOSE: To investigate whether a beverage containing glucose and fructose would result in greater deuterium accumulation in plasma and saliva than glucose METHODS: Six male subjects were recruited (Age 22 ± 2 years). Subjects entered the laboratory between 7 and 9 am after an overnight fast. Subjects rested for 20 min after which resting blood and saliva samples were collected. A 600 ml bolus of one of the three experimental beverages was given. The experimental beverages were (water (W), water with 75g glucose (G) or water with 50g glucose and 25g fructose (GF), each beverage also contained 3.00 g of 2H2O. Following administration of the experimental beverage subjects remained in a seated position for 180 min. Blood and saliva samples were then taken every 5 min in the first hour and every 15 min thereafter. Plasma and saliva samples were analysed for 2H enrichment by isotope ratio mass spectrometry. Deuterium enrichments for plasma and saliva were compared using a 2-way repeated measures ANOVA. Area under the curve (AUC) and time to peak was analysed using a 1-way repeated measures ANOVA. Post hoc analysis were completed using Tukey LSD. Significance was set at p<0.05. RESULTS: There was a significant interaction between the three trials for plasma enrichment. W trial was significantly greater then G at all time points between 5 and 105 min, but only greater than GF between 20 and 35 min. GF was significantly greater than G between 55 and 75 min. There was no difference between any trials after 120 min. There was no difference between plasma and saliva enrichment in the final hour. There was no significant effect of the three trials for saliva enrichment. The water trial (33 ± 3 min) showed a significantly quicker time to peak than either G (82 ± 40 min) or GF (59 ± 25 min) but there was no difference between G and GF. The significantly greater AUC for GF (55673 ± 10020 ▪‰ vs VSMOW. 180min) and W (60497 ± 9864 ▪‰ vs VSMOW. 180min) compared to G (46290 ± 9622 ▪‰ vs VSMOW. 180min) suggest greater fluid delivery for GF and W compared to G. However, W and GF were not significantly different from each other. CONCLUSION: These data suggest that an 11 % carbohydrate beverage containing glucose and fructose RESULTS in more rapid fluid delivery in the first 75min than a beverage containing glucose alone.