Today, we’re looking at glutamine’s protective role for endurance athletes.
Approx. 30-65% of marathon runners/triathletes experience some kind of gut distress, ranging from nausea, vomiting, abdominal cramps and the sudden urge to not shit yourself. Agree?
When training starts, blood flow gets redirected from the gut to the working muscles as they have a higher priority for oxygen. Therefore, the reduced blood supply to the gut during exercise is thought to cause damage to the intestinal wall.
In return, increases the permeability of the gut wall where larger, normally restricted molecules pass through into the blood, such as certain endotoxins. These endotoxins in particular have been related to nausea, vomiting and diarrhea.
In addition, the loss of gut function can impact; bacterial translocation, intestinal inflammation, nutrient uptake and subsequently performance and recovery. This appears to get worse when training or competing in the heat.
Glutamine, a naturally occurring non-essential amino acid plays a number of roles within the gut, in particular acting as a fuel source for cells in the gut and immune system. Interestingly, this has been shown to cause gut permeability following glutamine depletion within the intestinal barrier.
Previous research has shown that taking 0.9g of glutamine per kilogram of fat free mass (g/kg/FFM) both 2 hours before and daily for 7 days restores intestinal barrier function and reduces permeability. This however, is a pretty huge dose, i.e. 61g of glutamine for a 80kg athlete with 15% body fat.
The question is, can we get away with less?
Well, Pugh et al (2017) put 10 lads to the test to find out how taking either 0.25g, 0.5g and 0.9g/kg/FFM would work 2 hours before a 60 min run in the heat.
To keep this short, a lower dose of 0.25g/kg FFM (17g) did reduce gut damage/permeability by 25% when measured post exercise, but not quite as good as the higher dose of 0.9g/kg/FFM (61g) which appeared to be 15% better.
The question is, how well would glutamine work with more damaging sports such as rugby? Also, how would gut issues be when taken amongst other nutrition strategies pre events; beet it shots, caffeine, carb loading, creatine etc?
For those who do experience this, it could be another valuable tool added to your tool box!