Strenuous physical activity is known to generate reactive oxygen species to a point that can exceed the antioxidant defense system and lead to oxidative stress. Dietary intake of antioxidants, plasma enzymatic (superoxide dismutase, glutathione reductase [Gr], and glutathione peroxidase [GPx]) activities, nonenzymatic (total antioxidant status [TAS], uric acid, α-tocopherol, retinol, α-carotene, β-carotene, lycopene, and lutein + zeaxanthin) antioxidants, and markers of lipid peroxidation (thiobarbituricacid-reactive substances [TBARS]) and muscle damage (creatine kinase [CK]) were measured in 17 elite male kayakers and canoeists under resting conditions and in an equal number of age- and sex-matched sedentary individuals. Athletes showed increased plasma values of α-tocopherol (p = .037), α-carotene (p = .003), β-carotene (p = .007), and superoxide dismutase activity (p = .002) and a lower TAS level (p = .030). Antioxidant intake (α-tocopherol, vitamin C, and β-carotene) and plasmatic GPx, Gr, lycopene, lutein + zeaxanthin, retinol, and uric acid levels were similar in both groups. Nevertheless, TBARS (p < .001) and CK (p = .011) levels were found to be significantly higher in the kayakers and canoeists. This work suggests that despite the enhanced levels of antioxidants, athletes undergoing regular strenuous exercise exhibited more oxidative stress than sedentary controls.
Vitor Teixeira, Hugo Valente, Susana Casal, Franklim Marques and Pedro Moreira
Stephanie Whisnant Cash, Shirley A.A. Beresford, Thomas L. Vaughan, Patrick J. Heagerty, Leslie Bernstein, Emily White and Marian L. Neuhouser
Limited evidence suggests that very high-intensity exercise is positively associated with DNA damage but moderate exercise may be associated with DNA repair.
Participants were 220 healthy, Washington State 50- to 76-year-olds in the validity/biomarker substudy of the VITamins And Lifestyle (VITAL) cohort, who provided blood samples and completed questionnaires assessing recent physical activity and demographic and health factors. Measures included nested activity subsets: total activity, moderate- plus high-intensity activity, and high-intensity activity. DNA damage (n = 122) and repair (n = 99) were measured using the comet assay. Multivariate linear regression was used to estimate regression coefficients and associated 95% confidence intervals (CIs) for relationships between MET-hours per week of activity and each DNA outcome (damage, and 15- and 60-minute repair capacities).
DNA damage was not associated with any measure of activity. However, 60-minute DNA repair was positively associated with both total activity (β = 0.21, 95% CI: 0.0057–0.412; P = .044) and high-intensity activity (β = 0.31, 95% CI: 0.20–0.60; P = .036), adjusting for age, sex, BMI, and current multivitamin use.
This study is the first to assess broad ranges of activity intensity levels related to DNA damage and repair. Physical activity was unrelated to DNA damage but was associated with increased repair.
This study assessed the nutrient intake and eating behavior in Norwegian female elite athletes suffering from eating disorders (ED) who met the criteria for anorexia nervosa (AN), anorexia athletica (AA), or bulimia nervosa (BN). The subjects included 7 AN, 43 AA, 42 BN, and 30 controls. Three-day and 24-hr food records were used to assess energy and nutrient intake. Results revealed that a significant number of AN and AA athletes have diets too low in energy and nutrients, the mean intake for energy and CHO being lower than recommended for active females. A significant number did not reach the protein level recommended for athletes. In addition, there were low intakes of several micronutrients, most notably calcium, vitamin D, and iron. The energy and nutritional inadequacy, combined with the use of purging, are of major concern since the athletes in this study were relatively young. It is unknown whether the abnormal eating pattern is a consequence of ED or is typical of top level athletes.
Flatwater kayaking requires upper-body muscle strength and a lean body composition. This case study describes a nutrition intervention with a 19-year-old male elite sprint kayaker to increase muscle mass and improve recovery posttraining. Before the intervention, average daily energy intake was 13.6 ± 2.5 MJ (M ± SD; protein, 1.8 g/kg; carbohydrate, 3.6 g/kg), and the athlete was unable to eat sufficient food to meet the energy demands of training. During the 18-month intervention period, the athlete’s daily energy intake increased to 22.1 ± 3.8 MJ (protein, 3.2 g/kg; carbohydrate, 7.7 g/kg) by including milk-based drinks pre- and posttraining and before bed and an additional carbohydrate-based snack midmorning. This simple dietary intervention, along with a structured strength and conditioning program, resulted in an increase of 10 kg body mass with minimal change in body fat percentage. Adequate vitamin D status was maintained without the need for supplementation during the intervention period. In addition, the athlete reported the milk-based drinks and carbohydrate snacks were easy to consume, and no adverse side effects were experienced. This was the first time the athlete was able to maintain weight during intensive phases of the training cycle.
Edith M. Peters and Jeni M. Goetzsche
Training (T) and prerace (PR) dietary intakes of male and female athletes participating in a 90-km ultramarathon and the usual diets of matched, sedentary controls were investigated using 24-hr dietary records. Supplement use, mean weekly training distance, and race performance times were recorded. Macro- and micronutrient intakes were analyzed using computerized nutritional analysis programs. Total mean energy intake in the T and PR diets of the runners was 10.1 and 12.8 MJ in the men (n = 150) and 7.5 and 9.1 MJ in the women (n = 23). Mean relative contribution of CHO to the runners' total kilojoule intake increased from 50.0 and 49.5% in the T diets to 57.7 (p < .05; n = 153) and 56.4% (p < .05; n = 23) in the PR diets of male and female runners, respectively, and energy-boosting supplements were included in the PR diets of 48% of female and 59% of male runners. Seventy-eightpercent of female and 62% of male runners used vitamin and mineral supplements in their T diets as opposed to 39% of female and 28% of male controls. No statistically significant relationship was found between total kilojoule, CHO, fat, protein, and selected micronutrient intake during the 3 days before the race and performance in the 90-km event in runners of homogenous training status and gender.
Mikael Fogelholm, Seppo Rehunen, Carl-Gustav Gref, Juha T. Laakso, Jari Lehto, Lnkeri Ruokonen and Jaakko-Juhani Himberg
This study evaluated how different training periods affect dietary intake and biochemical indices of thiamin, iron, and zinc status in elite Nordic skiers. Subjects.were 17 skiers and 39 controls, ages 18-38 yrs. Dietary data were collected by 7-day food records at 3-month intervals. Coefficient of variation (CV) was used to indicate magnitude of seasonal changes. Energy intake for the year (28 food record days) was 3,802 kcallday (CV 19.1%) in male skiers, 2,754 kcallday (CV 3.7%) in male controls, 2,812 kcallday (CV 9.1%) in female skiers, and 2,013 kcallday (CV 5.9%) in female controls. CVs for thiamin, riboflavin, vitamin C, calcium, magnesium, iron, and zinc intake were 14.1-23.9% (male skiers), 2.9-15.0% (male controls), 4.8-24.5% (female skiers), and 4.3-1 1.5% (female controls). Seasonal changes in energy, carbohydrate, and micronutrient intakes reflected energy expenditure in male endurance athletes particularly. Erythrocyte transketolase activation coefficients and serum ferritin and zinc concentrations did not differ between skiers and controls. Seasonal variations in these biochemical indices of nutritional status were of the same magnitude in skiers and controls, despite large changes in skiers' physical activity.
Ben Desbrow, Joanna McCormack, Louise M. Burke, Gregory R. Cox, Kieran Fallon, Matthew Hislop, Ruth Logan, Nello Marino, Susan M. Sawyer, Greg Shaw, Anita Star, Helen Vidgen and Michael Leveritt
It is the position of Sports Dietitians Australia (SDA) that adolescent athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the demands of growth and development. As such, SDA established an expert multidisciplinary panel to undertake an independent review of the relevant scientific evidence and consulted with its professional members to develop sports nutrition recommendations for active and competitive adolescent athletes. The position of SDA is that dietary education and recommendations for these adolescent athletes should reinforce eating for long term health. More specifically, the adolescent athlete should be encouraged to moderate eating patterns to reflect daily exercise demands and provide a regular spread of high quality carbohydrate and protein sources over the day, especially in the period immediately after training. SDA recommends that consideration also be given to the dietary calcium, Vitamin D and iron intake of adolescent athletes due to the elevated risk of deficiency of these nutrients. To maintain optimal hydration, adolescent athletes should have access to fluids that are clean, cool and supplied in sufficient quantities before, during and after participation in sport. Finally, it is the position of SDA that nutrient needs should be met by core foods rather than supplements, as the recommendation of dietary supplements to developing athletes over-emphasizes their ability to manipulate performance in comparison with other training and dietary strategies.
Mandy Clark, Debra B. Reed, Stephen F. Crouse and Robert B. Armstrong
Little published data describe the dietary and physiological profiles of intercollegiate female soccer players; therefore, the purpose of this investigation was to report baseline dietary data, anthropometrics, and performance indices of soccer women during rigorous pre-season training (2 sessions/day) and then during the post-competitive season. Members of a NCAA Division I women’s soccer squad completed 3-day diet records, anthropometrics, and physical tests, including VO2peak. Average body mass was 62 kg with 16% body fat, and no significant pre to post differences were observed. Total energy, carbohydrate (CHO), protein, and fat intakes were significantly greater during the pre-sea-son. Pre-season energy intake met the DRI for females with an “active” lifestyle (37 kcal/kg). While CHO intake failed to meet minimum recommendations to promote glycogen repletion (7–10 g/kg), protein and fat intakes were above minimum recommendations. Pre- and post-season intakes of several micronu-trients were marginal (<75% of the DRI) including vitamin E, folate, copper, and magnesium. VO2peak significantly improved from pre- to post-season (42 and 50 ml/kg/min). In this study female soccer players appeared to meet caloric needs during periods of training but failed to meet minimum CHO and micronu-trient recommendations. Foods higher in protein and fat displaced more CHOrich and nutrient-dense foods within athletes’ energy requirements and satiety limits.
Sherry Robertson, Dan Benardot and Margo Mountjoy
The sport of synchronized swimming is unique, because it combines speed, power, and endurance with precise synchronized movements and high-risk acrobatic maneuvers. Athletes must train and compete while spending a great amount of time underwater, upside down, and without the luxury of easily available oxygen. This review assesses the scientific evidence with respect to the physiological demands, energy expenditure, and body composition in these athletes. The role of appropriate energy requirements and guidelines for carbohydrate, protein, fat, and micronutrients for elite synchronized swimmers are reviewed. Because of the aesthetic nature of the sport, which prioritizes leanness, the risks of energy and macronutrient deficiencies are of significant concern. Relative Energy Deficiency in Sport and disordered eating/eating disorders are also of concern for these female athletes. An approach to the healthy management of body composition in synchronized swimming is outlined. Synchronized swimmers should be encouraged to consume a well-balanced diet with sufficient energy to meet demands and to time the intake of carbohydrate, protein, and fat to optimize performance and body composition. Micronutrients of concern for this female athlete population include iron, calcium, and vitamin D. This article reviews the physiological demands of synchronized swimming and makes nutritional recommendations for recovery, training, and competition to help optimize athletic performance and to reduce risks for weight-related medical issues that are of particular concern for elite synchronized swimmers.
Martin D. Hoffman, Linjun Chen and Eswar Krishnan
Little is known about the sociodemographics and lifestyle behaviors of ultramarathon runners, and the effects of these characteristics on body weight and body mass index (BMI).
We cross-sectionally analyzed baseline data of 1212 ultramarathoners on sociodemographics, lifestyle behaviors and BMI from the initial 12-month enrollment period in a longitudinal observational study.
The ultramarathoners were mostly middle-aged men who were more educated, more likely to be in a stable relationship, and more likely to use over-the-counter vitamins/supplements than the general population. They appear to gain less body weight with advancing age than the general population. Factors with the greatest effect on current BMI were BMI at 25 years of age and sex, which explained 48% and 3% of the variance. Negligible, but statistically significant direct relationships, with BMI were observed for age, work hours per week, television watching hours per week, and composite fat consumption frequency score. Negligible, but statistically significant inverse relationships, with BMI were observed for running distance during the prior year, and composite fruit and vegetable consumption frequency score.
While lifestyle decisions were found to impact BMI within this group of ultramarathoners, BMI at age 25 was the strongest predictor of current BMI.