The Ironman® triathlon is an ultra-endurance event. It has previously been shown that heavy training schedules and racing ultra-endurance events can lead to immune impairment. Evidence supporting the potential role of dietary intake and body composition on immune impairment or upper respiratory tract infections (URTIs) is currently lacking. Aim: To investigate the relationship between dietary intake, body composition and the incidence of URTI in triathletes residing in Port Elizabeth (PE), during training and competition for the Ironman® 2011 triathlon. Method: An observational longitudinal descriptive study with an analytical component was conducted. The study population included triathletes living in PE, who completed an Ironman® distance event one year prior to, and who were training for the April 2011 Ironman®. Habitual dietary intake was assessed with a quantitative food frequency questionnaire; and race dietary strategies with a three day food record. Body composition was determined with anthropometry and the incidence of URTI was assessed with the WURSS-44. A general health screen (SF-36) was also administered. Results: Habitual dietary intake during the three months pre- and post-Ironman® 2011 triathlon was adequate for all nutrients except for carbohydrate intake in female and male participants (pre-Ironman® of 4.0 (1.7) g/kg body weight (BW)/day and 5.4 (1.8) g/kg BW/day; and post-Ironman® 3.0 (1.0) g/kg BW/day and 4.7 (1.5) g/kg BW/day respectively). Carbohydrate-loading strategies were below recommendations with intakes of 6.0 (2.9) and 5.1 (2.5) g/kg BW/day for female and male participants respectively. Race day nutrition strategies were below recommendations for carbohydrate intake. Post-race dietary intake was below recommendations for carbohydrate in the female participants (0.9 (0.5) g/kg BW). Body mass index was 26.6 (3.4) kg/m2 and 26.1 kg/m2 (1.40) for female and male study participants respectively. Body fat percentage was at the upper end for endurance athletes (29.3 (9.4) % and 13.7 (5.1) % for females and males respectively). In this study 25 % of the triathletes (N=20) developed an episode of URTI during the 3 months post-Ironman®. Dietary intake parameters measured three months pre-Ironman® that had a significant influence on URTI were: potassium (p=0.04) and thiamine (p=0.02) and dietary intake parameters measured 3 months post-Ironman® that had a significant influence on URTI were: total protein (p=0.04); isoleucine (p=0.03); leucine (p=0.03); phenylalanine (p=0.03); valine (p=0.02); thiamine (p=0.01); and Beta-tocopherol (p=0.03). Dietary intake parameters measured during the race that had a significant influence on URTI were: selenium (p=0.04); folate (p=0.04) and proline (p=0.02). Body composition did not have a significant influence on URTI. Conclusion: Habitual dietary intake three months pre- and post-Ironman® as well as pre- and post Ironman race strategies were low for carbohydrate. Body composition indicated that athletes were at the upper end associated with endurance sport. There was a relationship found between an episode of URTI and dietary intake.
© Copyright 2013 Alle Rechte vorbehalten.