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Carbohydrate and protein intake during exertional heat stress ameliorates intestinal epithelial injury and small intestine permeability

journal contribution
posted on 13.04.2022, 00:50 by Rhiannon MJ Snipe, Anthony Khoo, Cecilia KiticCecilia Kitic, Peter R Gibson, Ricardo JS Costa
Exertional heat stress (EHS) disturbs the integrity of the gastrointestinal tract leading to endotoxaemia and cytokinaemia, which have symptomatic and health implications. This study aimed to determine the effects of carbohydrate and protein intake during EHS on gastrointestinal integrity, symptoms, and systemic responses. Eleven (male, n = 6; female, n = 5) endurance runners completed 2 h of running at 60% maximal oxygen uptake in 35°C ambient temperature on 3 occasions in randomised order, consuming water (WATER), 15 g glucose (GLUC), or energy-matched whey protein hydrolysate (WPH) before and every 20 min during EHS. Rectal temperature and gastrointestinal symptoms were recorded every 10 min during EHS. Blood was collected pre- and post-EHS, and during recovery to determine plasma concentrations of intestinal fatty-acid binding protein (I-FABP) as a marker of intestinal epithelial injury, cortisol, endotoxin, and inflammatory cytokines. Urinary lactulose/L-rhamnose ratio was used to measure small intestine permeability. Compared with WATER, GLUC, and WPH ameliorated EHS associated intestinal epithelial injury (I-FABP: 897 ± 478 pg·mL−1 vs. 123 ± 197 pg·mL−1 and 82 ± 156 pg·mL−1, respectively, p < 0.001) and small intestine permeability (lactulose/L-rhamnose ratio: 0.034 ± 0.014 vs. 0.017 ± 0.005 and 0.008 ± 0.002, respectively, p = 0.001). Endotoxaemia was observed post-EHS in all trials (10.2 pg·mL−1, p = 0.001). Post-EHS anti-endotoxin antibodies were higher (p < 0.01) and cortisol and interleukin-6 lower (p < 0.05) on GLUC than WATER only. Total and upper gastrointestinal symptoms were greater on WPH, compared with GLUC and WATER (p < 0.05), in response to EHS. In conclusion, carbohydrate and protein intake during EHS ameliorates intestinal injury and permeability. Carbohydrate also supports endotoxin clearance and reduces stress markers, while protein appears to increase gastrointestinal symptoms, suggesting that carbohydrate is a more appropriate option.

History

Volume

42

Issue

12

Start Page

1283

End Page

1292

Number of Pages

10

eISSN

1715-5320

ISSN

1715-5312

Location

Canada

Publisher

Canadian Science Publishing

Language

eng

Peer Reviewed

Yes

Open Access

No

Acceptance Date

26/07/2017

External Author Affiliations

Monash University

Era Eligible

Yes

Medium

Print-Electronic

Journal

Applied Physiology, Nutrition and Metabolism