SYNOPSIS: [MAY 2022] A study from the University of Chichester has revealed that CurraNZ blackcurrant extract may offer benefits for athletes by preventing gastro-intestinal (GI) damage and permeability during exercise in the heat.
The study, performed by Dr Ben Lee, a thermal physiologist and now at Coventry University, has implications for those undertaking running exercises in the heat that are known to disrupt gastro-intestinal barrier and function.
The study showed that, following a bout of exertional heat stress, participants on CurraNZ blackcurrant extract experienced a large reduction in small intestinal permeability and heat-induced cell damage of up to 40%.
Twelve healthy recreationally active, unacclimatised men took 600mg of New Zealand blackcurrant extract – CurraNZ - for seven days before performing 60 minutes of moderate-intensity treadmill running in hot ambient conditions (34°C, 40% humidity).
Measurements were taken of intestinal fatty acid binding protein, a marker of enterocyte damage, at rest and 20, 60 and 240 minutes post-exercise.
The findings showed the intake of blackcurrant led to:
- 40% reduction in intestinal fatty acid binding protein (which indicates intestinal cell damage)
- 12% reduction in lactulose and rhamnose excretion (biomarkers that indicate intestinal permeability)
- No adverse effects on thermoregulation, with a slight reduction in deep body temperature
- 100% of the participants demonstrated improvements to GI function and integrity
Exercise in the heat is one of the most severe demands athletes can place on the gastro-intestinal system.
Up to 90% of endurance athletes are affected by symptoms of gastrointestinal distress during exercise in the heat, which are in part caused by a redistribution in blood flow away from the gut, leading to a host of symptoms that, if left uncontrolled, can impair exercise performance and may even lead to more severe outcomes such as heat illness.
The study’s robust findings are particularly relevant to those undertaking running-based exercises known to cause GI distress in the heat.
Lee et al. Anthocyanin-rich blackcurrant extract preserves gastrointestinal barrier permeability and reduces enterocyte damage but has no effect on microbial translocation and inflammation after exertional heat stress, IJSNEM (in press) doi: 10.1123/ijsnem.2021-0330.