Short-Term Very High Carbohydrate Diet and Gut-Training Have Minor Effects on Gastrointestinal Status and Performance in Highly Trained Endurance Athletes

Nutrients

Nicolin Tee¹  Philo U. Saunders¹  Ricardo J. S. Costa²  Stephanie K. Gaskell²  Louise M. Burke³  Megan L. Ross³  Andy J. King³  Ida A. Heikura³  Alannah K. A. McKay³  Laura Garvican-Lewis³  Nicole A. Beard⁴  Naroa Etxebarria⁵  Avish P. Sharma⁶  Sara F. Forbes⁷ 

[1] Australian Institute of Sport, Leverrier Street, Canberra, ACT 2617, Australia;Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, VIC 3800, Australia;Exercise & Nutrition Research Program, The Mary Mackillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3065, Australia;Faculty of Science and Technology, University of Canberra, Bruce, ACT 2617, Australia;Research Institute for Sport and Exercise, University of Canberra, Bruce, ACT 2617, Australia;School of Allied Health Sciences, Griffith University, Gold Coast, QLD 4222, Australia;UniSA Online, University of South Australia, Adelaide, SA 5001, Australia;

关键词: nutrition;    exercise;    marathon;    athletic performance;    gastrointestinal symptoms;    intestinal fatty acid binding protein;   

DOI  :  10.3390/nu14091929

来源: DOAJ

【 摘 要 】

We implemented a multi-pronged strategy (MAX) involving chronic (2 weeks high carbohydrate [CHO] diet + gut-training) and acute (CHO loading + 90 g·h⁻¹ CHO during exercise) strategies to promote endogenous and exogenous CHO availability, compared with strategies reflecting lower ranges of current guidelines (CON) in two groups of athletes. Nineteen elite male race walkers (MAX: 9; CON:10) undertook a 26 km race-walking session before and after the respective interventions to investigate gastrointestinal function (absorption capacity), integrity (epithelial injury), and symptoms (GIS). We observed considerable individual variability in responses, resulting in a statistically significant (p < 0.001) yet likely clinically insignificant increase (Δ 736 pg·mL⁻¹) in I-FABP after exercise across all trials, with no significant differences in breath H₂ across exercise (p = 0.970). MAX was associated with increased GIS in the second half of the exercise, especially in upper GIS (p < 0.01). Eighteen highly trained male and female distance runners (MAX: 10; CON: 8) then completed a 35 km run (28 km steady-state + 7 km time-trial) supported by either a slightly modified MAX or CON strategy. Inter-individual variability was observed, without major differences in epithelial cell intestinal fatty acid binding protein (I-FABP) or GIS, due to exercise, trial, or group, despite the 3-fold increase in exercise CHO intake in MAX post-intervention. The tight-junction (claudin-3) response decreased in both groups from pre- to post-intervention. Groups achieved a similar performance improvement from pre- to post-intervention (CON = 39 s [95 CI 15–63 s]; MAX = 36 s [13–59 s]; p = 0.002). Although this suggests that further increases in CHO availability above current guidelines do not confer additional advantages, limitations in our study execution (e.g., confounding loss of BM in several individuals despite a live-in training camp environment and significant increases in aerobic capacity due to intensified training) may have masked small differences. Therefore, athletes should meet the minimum CHO guidelines for training and competition goals, noting that, with practice, increased CHO intake can be tolerated, and may contribute to performance outcomes.

【 授权许可】

Unknown