The purpose of this investigation was to determine the effects of antioxidant supplementation on DNA damage following exercise. Fourteen subjects were randomly assigned to one of two groups and required to ingest either antioxidants (400 mg α-lipoic acid, 200 mg co-enzyme Q10, 12 mg manganese, 600 mg vitamin C, 800 mg N-acetyl cysteine, 400 μg selenium, and 400 IU α-tocopherol per day) or placebos for 7 d. Exercise increased DNA damage, PS, FRAP, and LDH (P < 0.05), but not selectively between groups. LDH and PS concentration decreased 1 h post-exercise (P < 0.05), while LH concentration decreased 1 h post-exercise in the antioxidant group only (P < 0.05). The antioxidant group had a higher concentration of LH (P < 0.05), perhaps due to a selective difference between groups post-exercise (P < 0.05). The main findings of this investigation demonstrate that exhaustive aerobic exercise induces DNA damage, while anti-oxidant supplementation does not protect against damage.
G.W. Davison, C.M. Hughes and R.A. Bell
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.
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.
John D. Robertson, Ronald J. Maughan, Ann C. Milne and Ronald J.L. Davidson
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.
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.
Jongkyu Kim, Seung-ki Kang, Han-sang Jung, Yoon-suck Chun, Jennifer Trilk and Seung Ho Jung
Athletes report frequent use of various dietary supplements (DSs). However, no study has examined DS use and antidoping knowledge in Korean Olympians. The objectives of this study were to obtain information about Korean Olympians’ DS use during the training period for the Beijing 2008 Summer Olympic Games and immediately before their Olympic events, to obtain DS-intake reasons and DS providers, and to obtain information on athletes’ doping education, knowledge, and educators. Korean Olympians completed 2 questionnaires 1 wk before the opening and within 1 wk after the closing of the Beijing 2008 Summer Olympic Games. Results showed that 79% of male and 82% of female Olympians take more than 1 DS during the training period and that vitamins and Oriental supplements are the 2 top-ranked DSs. Reasons for DS use were to improve recovery ability (66%) and muscle performance (22%), and sources of obtaining DSs were parents (36%) and coaches (35%). Furthermore, 79% of Korean Olympians reported receiving regular education on antidoping regulations from Olympic-sponsored education classes (64%) and coaches (15%). In conclusion, this study was the first to examine DS use and antidoping-related information in Korean Olympians. Because some herbal products contain substances banned by the World Anti-Doping Agency, athletes should be cautious in using mixed Oriental supplements.
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.
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.
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.
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.