Blood biochemical indices of iron status were measured in venous blood from 20 runners and 6 control subjects. All subjects were.male, ages 20 to 40 years, and stable with regard to body weight and degree of physical activity. Dietary analysis was undertaken using a 7-day weighed food intake. There was no evidence of iron deficiency: hemoglobin concentrations and serum femtin levels were within the normal population range for all individuals. However, serum ferritin was negatively correlated with the amount of training. Daily iron intake appeared to be adequate; iron intake was correlated with protein intake but not related to training or energy intake. Serum ferritin, an indicator of iron status, was significantly correlated with vitamin C intake but not iron intake. Serum transferrin concentration was higher in the group of athletes undertaking a high weekly training load compared with the control subjects, suggesting an alteration in iron metabolism although there was no evidence of increased erythropoiesis. The biological significance of this is unclear.
John D. Robertson, Ronald J. Maughan, Ann C. Milne and Ronald J.L. Davidson
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.
Valéria Cristina Provenza Paschoal and Olga Maria Silverio Amancio
The purpose of this study was to evaluate the body composition, dietary intake, use of nutritional supplements, and biochemical status of 8 Brazilian male elite swimmers, aged 18–21 years, participants at a national swimming competition. Data from the athletes were obtained through a 4-day food record, a fasting blood sample, and anthropometric measurements. The anthropometric results showed that body composition was compatible with sport category. The dietary assessment showed an adequate ingestion of calories, vitamins, and mineral, with the exception of calcium, for which only half of the sample reached the recommendation. The results also indicated low carbohydrate and high protein and cholesterol intakes. Of the swimmers, 62.5% and 25% consumed synthetic aminoacids and antioxidants supplements, respectively. The biochemical indices of the nutritional status were within normal limits in all swimmers, with the exception of creatine-kinase, which was above the recommended level, indicating muscle degradation probably due to poor carbohydrate intake. In conclusion, the results suggest the importance of nutritional education to promote a balanced intake, provide all nutrients in optimal amounts, inhibit unnecessary ingestion of nutritional supplements, maintain ideal performance, and improve the swimmers’ health status.
Vitor Teixeira, Hugo Valente, Susana Casal, Franklim Marques and Pedro Moreira
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.
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.
Nancy Clark, Cato Coleman, Kerri Figure, Tom Mailhot and John Zeigler
Every 4 years, rowers from around the world compete in a 50- to 60-day transAtlantic rowing challenge. These ultra-distance rowers require a diet that provides adequate calories, protein, vitamins, minerals, and fluids so they can perform well day after day, minimize fatigue, and stay healthy. Yet, the rowers are confronted with menu planning challenges. The food needs to be lightweight, compact, sturdy, non-spoiling in tropical temperatures, calorie dense, easy to prepare, quick to cook, and good tasting. Financial concerns commonly add another menu planning challenge. The purpose of this case study is to summarize the rowers’ food experiences and to provide guidance for sports nutrition professionals who work with ultra-endurance athletes embarking on a physical challenge with similar food requirements. The article provides food and nutrition recommendations as well as practical considerations for ultra-distance athletes. We describe an 8,000 calorie per day menu planning model that uses food exchanges based on familiar, tasty, and reasonably priced supermarket foods that provide the required nutrients and help contain financial costs.
Kristin Wiens, Kelly Anne Erdman, Megan Stadnyk and Jill A. Parnell
To evaluate dietary supplement use in young Canadian athletes, their motivation for consuming supplements, and their sources of information.
A questionnaire tested for content validity and reliability was administered to 567 athletes between the ages of 11 and 25 years from the Canadian athletic community in face-to-face meetings. Demographics and sport variables were analyzed using descriptive statistics. Fisher’s exact tests were used to examine dietary supplementation patterns and sources of information regarding dietary supplement use between categories of gender, age, sport type, and competition level.
Ninety-eight percent of athletes were taking at least one dietary supplement. Males were more likely to consume protein powder, energy drinks, recovery drinks, branched chain amino acids, beta-alanine, and glutamine (p < .01); supplements typically associated with increased muscle mass. Athletes 11–17 years old focused on vitamin and mineral supplements; whereas, athletes 18–25 years old focused on purported ergogenic supplements. Strength training athletes were more likely to consume creatine, glutamine, and protein powders (p < .02). Reasons for supplement use included to stay healthy, increase energy, immune system, recovery, and overall performance. Primary sources of information were family and friends, coaches, and athletic trainers; with 48% of athletes having met with a dietitian. Preferred means of education included individual consultations, presentations, and the internet.
The majority of young athletes are using dietary supplements with the belief they will improve performance and health; however, may not always have reliable information. Educational programs using individual consultations and electronic media are recommended for this demographic.
Christina Tsitsimpikou, Nastasia Chrisostomou, Peter Papalexis, Konstantinos Tsarouhas, Aristidis Tsatsakis and Athanasios Jamurtas
Although the use of nutritional supplements by professional athletes and the benefits thereof have been extensively studied, information on recreational athletes’ use of supplements is limited. This study investigated the consumption of nutritional supplements, source of information and supply of supplements, and level of awareness with regard to the relevant legislation among individuals who undertake regular exercise in Athens, Greece. A closed-ended, anonymous questionnaire was answered by 329 subjects (180 men, 149 women), age 30.6 ± 12.1 yr, from 11 randomly selected gym centers. Preparations declared as anabolic agents by the users were submitted to a gas chromatographic analyzer coupled to a mass spectrometric detector. Consumption of nutritional supplements was reported by 41% of the study population, with proteins/amino acids and vitamins being the most popular. Age (r = .456, p = .035), sex (χ2 = 14.1, df = 1, p < .001), level of education (χ2 = 14.1, df = 3, p < .001), and profession (χ2 = 11.4, df = 4, p = .022) were associated with the subjects’ decision to consume nutritional supplements. Most (67.1%) purchased products from health food stores. Only 17.1% had consulted a physician or nutritionist, and one third were aware of the relevant legislation. Two preparations were detected containing synthetic anabolic steroids not stated on the label. In conclusion, use of nutritional supplements was common among recreational athletes in Athens, Greece. A low level of awareness and low involvement of health care professionals as sources of information and supply were observed.
Susan Heaney, Helen O’Connor, Janelle Gifford and Geraldine Naughton
This study aimed to compare strategies for assessing nutritional adequacy in the dietary intake of elite female athletes.
Dietary intake was assessed using an adapted food-frequency questionnaire in 72 elite female athletes from a variety of sports. Nutritional adequacy was evaluated and compared using mean intake; the proportion of participants with intakes below Australian nutrient reference values (NRV), U.S. military dietary reference intakes (MDRI), and current sports nutrition recommendations; and probability estimates of nutrient inadequacy.
Mean energy intake was 10,551 ± 3,836 kJ/day with macronutrient distribution 18% protein, 31% fat, and 46% carbohydrate, consistent with Australian acceptable macronutrient distribution ranges. Mean protein intake (1.6 g · kg−1 · d−1) was consistent with (>1.2 g · kg−1 · d−1), and carbohydrate intake (4.5 g · kg−1 · d−1), below, current sports nutrition recommendations (>5 g · kg−1 · d−1), with 30% and 65% of individuals not meeting these levels, respectively. Mean micronutrient intake met the relevant NRV and MDRI except for vitamin D and folate. A proportion of participants failed to meet the estimated average requirement for folate (48%), calcium (24%), magnesium (19%), and iron (4%). Probability estimates of inadequacy identified intake of folate (44%), calcium (22%), iron (19%), and magnesium (15%) as inadequate.
Interpretation of dietary adequacy is complex and varies depending on whether the mean, proportion of participants below the relevant NRV, or statistical probability estimate of inadequacy is used. Further research on methods to determine dietary adequacy in athlete populations is required.
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.