Sugarcane extract (PRSE) modestly improves intestinal integrity markers and attenuates IL-8 in exertional-heat stress.

Exertional-heat stress (EHS), common in athletes and military personnel, significantly compromises gastrointestinal integrity, leading to increased gut permeability and subsequent systemic inflammation. This can manifest as severe symptoms and even necessitate medical intervention. Current strategies often fall short in effectively mitigating these issues. This study investigates whether a (poly)phenol-rich sugarcane extract (PRSE) can offer a natural, nutritional approach to support gut barrier function and modulate inflammatory responses during such strenuous conditions.

This double-blind, placebo-controlled crossover study involved n=14 participants who completed two Exertional-Heat Stress (EHS) trials, separated by a one-week washout. Participants consumed 2 × 270 mL of either PRSE (10% w/v) or a carbohydrate-matched placebo beverage daily for 14 days. On EHS trial days, they consumed 1 × 270 mL beverage pre-EHS and a PRSE gel (46% w/v) sachet every 20 min during the 2-hour EHS (running at 60% V˙O2max in 34.4 °C). Blood samples were collected at multiple time points to analyze plasma cortisol, I-FABP, sCD14, and systemic inflammatory cytokines via ELISA.

Compared to placebo, the PRSE trial resulted in a higher rectal temperature (p=0.046) and physiological strain index (p=0.010). While no Trial × Time interaction was observed for I-FABP, pre-EHS plasma I-FABP concentration was notably lower in the PRSE group. Plasma IL-8 concentration significantly increased over time (p<0.001) in both groups, but this increase was attenuated by PRSE compared with placebo (p=0.023). Exercise-associated gastrointestinal symptoms (Ex-GIS) incidence remained high in both trials; however, the average symptom severity was lower with PRSE. These findings suggest a targeted anti-inflammatory effect despite increased core temperature.

PRSE significantly attenuated the increase in plasma IL-8 concentration over time compared to placebo (p=0.023), indicating a reduction in systemic inflammatory response.