Addition of pectin-alginate to a carbohydrate beverage does not maintain gastrointestinal barrier function during exercise in hot-humid conditions better than carbohydrate ingestion alone

Abstract

Purpose: To compare the effects of consuming a 16% maltodextrin+fructose+pectin alginate (MAL+FRU+PEC+ALG) drink against a nutrient matched maltodextrin-fructose (MAL+FRU) drink on enterocyte damage and gastrointestinal permeability after cycling in hot and humid conditions. Methods: Fourteen recreational cyclists (7 men) completed three experimental trials in a randomized placebo-controlled design. Participants cycled for 90 min (45% VO2max) and completed a 15 min time-trial in hot (32°C) humid (70% relative humidity) conditions. Every 15-minutes cyclists consumed 143 mL of either (1) water; (2) MAL+FRU+PEC+ALG (90g CHO.hr/16% w/v), (3) – a ratio-matched MAL+FRU drink also (90g CHO.hr/16% w/v). Blood was sampled before and after exercise and gastrointestinal (GI) permeability determined by serum measurements of intestinal fatty acid-binding protein (IFABP) and the percent ratio of lactulose (5g) to rhamnose (2g) recovered in post-exercise urine. Results: Compared to WATER, IFABP decreased by 349±67pg.mL-1 with MAL+FRU+PEC+ALG (p=0.007), and by 427±56pg.mL-1 with MAL+FRU (p=0.02). GI permeability was reduced in both the MAL+FRU+PEC+ALG (by 0.019±0.01, p = 0.0003) and MAL+FRU (by 0.014±0.01, p = 0.002) conditions relative to WATER. Conclusion. Both CHO beverages attenuated GI barrier damage to a similar extent relative to water. No metabolic, cardiovascular, thermoregulatory or performance differences were observed between the CHO beverages. 
 Novelty bullets
 • Consumption of multiple-transportable CHO, with or without hydrogel properties, preserves GI barrier integrity and reduces enterocyte damage during prolonged cycling in hot-humid conditions. 

Carbohydrate Hydrogel Products Do Not Improve Performance or Gastrointestinal Distress During Moderate-Intensity Endurance Exercise

“…Mears et al (2020b) and Baur et al (2019) found no differences in relative substrate contribution during submaximal cycling at 50% W max but the nonsignificant increase in fat oxidation (and decrease in CHO oxidation) reported by Baur et al (2019) is notable, and consistent with Barber et al (2020). Flood et al (2020) also reported similar CHO and fat oxidation with CHO and hydrogel ingestion during low-intensity cycling. However, Baur et al (2019) also noted lower absolute total CHO and fat (to Mears et al [2020b] in both conditions), despite similar ingestion rates (68 and 78 g.hr -1 ).…”

“…Performance was similar with MD + F hydrogel, isocaloric MD + F fluids (Figure 3; Baur et al, 2019;Flood et al, 2020;McCubbin et al, 2019;Mears et al, 2020b), or noncaloric hydrogel (Pettersson et al, 2019). Relative performance changes between CHO hydrogel and fluids ranged between +1.05% and +3.8% but were not statistically significant (p < .05).…”

“…All studies were randomized controlled crossover trials. They investigated trained male athletes (VO 2 max 55-70 ml•kg −1 •min −1 ), with the exception of Pettersson et al (2019) and (Flood et al, 2020), who included six female cross-country skiers (VO 2 max: 59.9 ± 2.6 ml•kg −1 •min −1 ) and seven female cyclists (54.3 ± 12.3 ml•kg −1 •min −1 ). Exercise modes included cycling (four studies), running (one), and cross-country skiing (one).…”

“…A period of fixed-intensity exercise was included in all protocols (90-180 min) with five of the six studies then measuring exercise performance/ capacity using a time trial (three studies), time to exhaustion test (one), or repeated sprint test (one). Each of the studies in which performance was measured involved a preexercise meal according to current recommendations (Burke et al, 2011) or a self-selected "CHO-rich" meal (Flood et al, 2020). The only study undertaken under fasting conditions (Barber et al, 2020) focused on exogenous CHO oxidation as the primary outcome, which is not affected by prior muscle glycogen content (Margolis et al, 2019).…”

A Hydrogel Drink With High Fructose Content Generates Higher Exogenous Carbohydrate Oxidation and a Reduced Drop in Dental Biofilm pH Compared to Two Other, Commercially Available, Carbohydrate Sports Drinks

“…This finding is in accord with a recent study where ingestion of a 500 mL bolus of a 18% carbohydrate drink containing 0.4 g pectin and 0.6 g of alginate resulted in 1.8 and 2.4 times faster gastric half-emptying time compared to an isoenergetic MD+FRU drink and a glucose+FRU drink, respectively (42). Recent studies have found no difference in total substrate oxidation and blood glucose concentrations (43)(44)(45) or exogenous carbohydrate oxidation (46) with the addition of sodium alginate and pectin in drinks matched for maltodextrin and fructose content during exercise.…”