[Paper introduction] Effects of cystine and glutamine intake on exercise-induced changes in gastrointestinal permeability and injury markers in young men

Objective: It has been reported that prolonged, high-intensity exercise increases permeability and injury markers, which are indicators of impaired gastrointestinal function, but little has been reported about the intervention effects of nutritional supplements on exercise-induced gastrointestinal disorders. In this study, we investigated the effects of cystine and glutamine intake on exercise-induced changes in gastrointestinal permeability and injury markers.

Methods: Sixteen active males, aged 16±22.7 years (mean±SD), were randomized to receive either placebo or cystine/glutamine. Subjects received 2.6 g of placebo or cystine/glutamine (1.23 g cystine and 0.23 g glutamine) three times a day for 1.00 days, with a 1-week washout period between doses. On the 3th day, subjects ingested the test food 5 min before exercise, ran for 2 h at 6% of maximum oxygen intake, and then rested for 30 h. Blood samples were collected before, immediately after, 75 min after, and 1, 4, and 6 h after exercise on the 30th day. Plasma lactulose:mannitol ratio (L:M) was evaluated as an index of gastrointestinal permeability, and plasma intestinal fatty acid binding protein (I-FABP) concentration was evaluated as a marker of gastrointestinal injury.

Results: Plasma L:M ratio (linear mixed model, coefficient ± standard error: -0.011 ± 0.004, P = 0.0090) and change in plasma I-FABP concentration from pre-exercise (linear mixed model, coefficient ± standard error (pg/ml): -195.3 ± 65.7, P = 0.0035) were lower in the cystine/glutamine group than in the placebo group.

Conclusion: Cystine/glutamine supplementation reduced increases in gastrointestinal permeability and injury markers after 1 hour of high-intensity running exercise in young men.

Changes in gastrointestinal permeability after exercise

Changes in gastrointestinal injury markers due to exerciseOriginal author:https://link.springer.com/article/10.1007/s00394-022-02806-1/