Nutrition for the young athlete

Nutrition Knowledge and Perceived Dietary Requirements of Adolescent Student-Athletes: A Pilot Study

BACKGROUND/OBJECTIVES

Adherence to sports-specific nutritional guidelines can help optimize athlete performance and health. However, adolescent athletes may not have adequate nutrition knowledge and understanding of specific nutritional requirements. The objective of the current study was to examine the nutrition knowledge and perceived dietary requirements of adolescent athletes.

METHODS

Male (n = 29, age: 15.7 ± 1.3 yrs.; height: 178.9 ± 8.3 cm; body mass: 74.7 ± 17.2 kg; body fat %: 13.9 ± 7.9%) and female (n = 15, age: 16.5 ± 1.4 yrs.; height: 169.9 ± 6.5 cm; body mass: 63.3 ± 4.5 kg; body fat %: 23.7 ± 3.8%) secondary school student-athletes completed body composition testing (hydrostatic weighing) and electronic surveys (Abridged Sports Nutrition Knowledge Questionnaire (ASNKQ); self-perception of dietary energy and macronutrient requirements).

RESULTS

Athletes demonstrated poor sports nutrition knowledge, with no differences observed between sexes for the number of questions answered correctly (males: 45.1 ± 9.8% vs. females: 43.1 ± 12.7%; p = 0.57). No relationships were observed between ASNKQ scores and body composition parameters or between ASNKQ scores and self-reported perception of dietary energy and macronutrient requirements (p > 0.05). Athletes self-reported a lower perceived energy (-560 ± 1272 kcal/d; p = 0.014) and carbohydrate intake (-73 ± 376 g/d; p = 0.014) requirement compared to calculated nutritional recommendations. Athletes self-reported a higher perceived protein intake (263 ± 586 g/d; p = 0.026) requirement compared to calculated nutritional requirements.

CONCLUSIONS

The current sample of adolescent athletes from the secondary school level appears to have a poor level of sports nutrition knowledge and understanding of energy and macronutrient requirements.

Junior athletes' nutritional demands: a narrative review of consumption and prevalence of eating disorders

Information regarding the dietary requirements and consumption of young athletes is limited. Hence, the aim of this narrative review is to provide a comprehensive combination of research and review papers on the nutritional status of young athletes aged 5-18 years old, as well as quantitative, qualitative, wholesome foods, food choices, and eating disordered data concerning the dietary requirements for growing young athletes. This study involved systematic searches of electronic databases, including Google Scholar, PubMed, Science Direct, Scopus, and Web of Science. The specific criteria for identifying research papers published in English from July 1980 until May 2024 were included. Only 48 studies out of 1,262 were included in this narrative review. The findings of this study suggest that, compared with adults, junior athletes need a unique approach to meet their dietary needs. Growth, development, and general athletic performance depend on macronutrients, as they are vital nutrients for young active athletes. However, research on enhancing junior athletes' performance is still in progress, and studies on hydration status, and eating disorders are limited.

Nutrition knowledge, body image and food security risk amongst development rugby league players

BACKGROUND

This study aimed to describe the nutrition knowledge, food security risk and eating disorder risk of development male rugby league players.

METHODS

Sixty athletes from one Australian professional rugby league club volunteered. A cross sectional online survey questionnaire consisted of three sections (Eating Disorders Inventory (EDI-3), Nutrition Knowledge and Food Security). All athletes completed the online survey without assistance using a personal electronic device.

RESULTS

The mean total knowledge score was 65.7±13.1%. There was a positive relationship between age and knowledge score, P=0.050, r2=0.06. The majority of players had breakfast everyday (N.=45, 73.8%), took pack lunches (N.=33, 55.0%), and had homemade evening meals (N.=55, 91.7%). The majority of players ate more than 1 hour before training (N.=45, 75%) and all players (n=60, 100%) ate within half an hour of training finishing. The majority of participants agreed that nutrition could influence physical and cognitive aspects of nutrition however, skill-based activities were perceived by fewer participants to be influenced by nutrition. The majority (N.=38, 63.3%) had high food security, six (10.0%) had marginal food security, whereas 10 (16.7%) and six (10.0%) had low and very low security respectively.

CONCLUSIONS

These results show a concerning levels of eating disorder risk, food insecurity and poor nutrition knowledge amongst male development rugby league players. However, it does show that they believe nutrition can impact their health and performance, and they do mostly appear to adhere to the nutrition principals for optimising health and performance.

Trends in Nutrition-Related Risk Factors Identified Post-Operatively in Patients Treated for a Lower-Extremity Injury

This study investigated trends within a custom Sports Nutrition Assessment for Consultation (SNAC) survey designed to identify nutrition-related risk factors among post-operative lower-extremity youth athletes. Athletes aged 8-18 years who completed the SNAC at a sports medicine institution after lower-extremity surgery were reviewed for associations between SNAC questions and age/sex differences. Of 477 patients (15.0 ± 2.0 years; 47.8% female), 319 (66.9%) answered 'yes' to at least one question and were identified for a consult, though 216 (64.3%) declined. The most frequent questions to prompt a consult were a desire to better understand nutrition for recovery (41.5%) and regularly skipping at least one meal a day (29.8%). Inter-question responses were often significantly related, especially regarding appetite changes, weight changes, and/or meal-skipping. While consult acceptance was not significantly different between sex/age, males were more likely to report a desire to better understand nutrition (p = 0.004) and a weight change (p = 0.019), and females were more likely to report struggling with dizziness/fatigue (p < 0.001). Additionally, older athletes reported an appetite change (p = 0.022), meal-skipping (p = 0.002), a desire to better understand nutrition (p < 0.001), a weight change (p < 0.001), and an effort/recommendation to change their body composition/weight (p = 0.005). These findings demonstrate a link between risky nutrition behaviors and physical detriments.

Investigating the interrelationships among food habits, sports nutrition knowledge, and perceived barriers to healthy eating: a study of adolescent swimmers

This cross-sectional study aims to explore the relationships between food habits, perceived barriers to healthy eating, and sports nutrition knowledge among adolescent swimmers. The study focuses on understanding how these factors interact and influence dietary choices in young athletes. A cohort of 52 adolescent swimmers aged 12-18 from Al Hussein Youth Club in Al-Hussein Sport City participated in the study. Data were collected through surveys assessing food habits, perceived barriers to healthy eating, and sports nutrition knowledge. Pearson Correlation analysis was employed to examine associations between variables, and stepwise regression analysis was used to identify predictors of food habits. The analysis revealed a significant positive association between food habits and sports nutrition knowledge (r = 0.393, p = 0.004). Knowledge emerged as a significant positive predictor of food habits (β = 0.393, p = 0.004), highlighting the influential role of sports nutrition knowledge in shaping the dietary choices of adolescent swimmers. However, the introduction of Barriers lacked significance, and individual predictors did not reach statistical significance. These findings underscore the importance of targeted interventions aimed at enhancing nutritional education among adolescent swimmers. Understanding the interplay between knowledge, barriers, and food habits provides valuable insights into the complex dynamics that influence the dietary choices of young athletes. Addressing these factors through tailored educational programs can promote healthier eating habits and optimize performance among adolescent swimmers. This study highlights the critical role of sports nutrition knowledge in shaping the dietary behaviors of adolescent swimmers. By addressing knowledge gaps and overcoming perceived barriers, targeted interventions can help improve food habits and enhance the overall health and performance of young athletes.

Body Weight Satisfaction, Comments, Nutrition and Injury Risk in 489 Adolescent Elite Athletes

Exposure to critical body weight comments in youth athletes could lead to decreased self-esteem, affect body image, and increase the risk of eating disorders and cause depressive symptoms. The aim was to explore differences between sex, body mass index, sports type, with regards to body weight satisfaction, exposure to critical body weight comments from their coach and nutrition status in adolescent elite athletes. A questionnaire about body weight, critical body weight comments and nutrition was distributed to 489 adolescent elite athletes and injury prevalence was monitored across 20 weeks. The results showed that almost one in four athletes (n=116, 24%) was not satisfied with their weight and 12% (n=59) had received critical body weight comments from their coach. Of the athletes who were unsatisfied with their body weight (n=116), 47% wanted to lose weight (n=55). A significant (p<0.05) higher proportion of ice hockey players and swimmers used nutritional supplements, were unsatisfied with their body weight, and were more exposed to critical body weight comments compared to athletes from other sports. Adolescent elite athletes as young as 15-16 years old are exposed to critical body weight comments from their coach and experience challenges with body weight satisfaction that is partly dependent on the sport-specific context.

The influence of accelerometer epoch length on physical activity output in adolescent athletes

Epoch in accelerometer measurements is an important option that affects the results of physical activity (PA) analysis. Many studies have been conducted to investigate the effect of epoch on PA output in adolescents, but few have been performed on highly active youth athletes. We aimed to examine the differences in energy expenditure and time spent in different activity intensities by applying various epoch lengths in adolescent athletes. The participants of this study comprised 31 male athletes aged 12 to 13 in basketball, soccer, and taekwondo teams. Athletes wore a tri-axial accelerometer attached to the right hip for 6 to 7 consecutive days, including sleeping time. Subsequently, the recorded data from the accelerometer were downloaded using the ActiLife software and analyzed by varying the epoch to 1, 10, 30, and 60 sec. Daily average metabolic equivalents (METs) increased as the epoch increased (F=2.918, P=0.037), showing a significant difference between 1 and 60-sec epochs. As epoch length increased, sedentary (0-1.5 METs) (F=94.001, P=0.000) and high intensity (6 METs and higher) activity time (F=3.536, P=0.017) decreased, while low (1.5-3 METs) (F=173.949, P= 0.000), moderate (3-6 METs) (F=70.792, P=0.000), and moderate-to-vigorous activity (3 METs and higher intensity) (F=34.683, P=0.000) times increased. Comparing PA among adolescent athletes by varying epoch settings of accelerometers revealed differences in PA levels and time spent in different activity intensities. Future studies should consider the characteristic changes in the PA outputs according to the epoch length in very active adolescent athletes.

The Influence of Gender on Food Consumption Patterns Among National-Level Adolescent Cyclists

Background and objective Adolescents in general make poor food choices due to a lack of awareness, social pressure, and other factors, leading to a faulty lifestyle. On the other hand, the adolescent athletic population is associated with a healthy eating pattern. In light of this, this study aimed to evaluate the eating behavior of adolescent cyclists competing at the national level. Methods A total of 50 national-level adolescent cyclists (26 males and 24 females) were assessed for eating behavior, daily food consumption patterns, and eating habits around exercise time by using a pre-tested validated questionnaire, Food Frequency Questionnaire (FFQ), and 24-hour Food Recall. Results The majority (82%) of the cyclists were non-vegetarians, followed by lacto-vegetarians (14%) and lacto-ovo vegetarians (14%). Of note, 72% of the cyclists consumed four meals consisting of breakfast, lunch, snacks, and dinner daily, while 28% skipped at least one of the meals. The preference for takeaways (52%) surpassed dine-outs (34%) and home-cooked (14%) food. Pre-training snack was consumed by 37% and post-training snack by 47%. Cyclists daily consumed breakfast cereals (76%), bread (94%), pulses (92%), fruits (100%), vegetables (62%), milk (84%), milk products (90%), egg (82%), poultry, fish, and meat (74%), dry fruits, nuts, and seeds (78%), and saturated fats (100%). Junk foods (94%) and sweetened beverages (70%) were consumed at least once a week. No significant difference was observed in eating behavior and daily food consumption pattern between male and female cyclists. Conclusion The eating behavior of adolescent cyclists was inclined towards the consumption of saturated fats, junk food, and sweetened beverages. Male and female athletes have similar food habits. There is a need for the implementation of behavior change-oriented nutrition strategies to inculcate healthy eating habits among adolescent cyclists.

The Impact of a 'Remotely-Delivered' Sports Nutrition Education Program on Dietary Intake and Nutrition Knowledge of Junior Elite Triathletes

Triathlon is a physically demanding sport, requiring athletes to make informed decisions regarding their daily food and fluid intake to align with daily training. With an increase in uptake for online learning, remotely delivered education programs offer an opportunity to improve nutritional knowledge and subsequent dietary intake in athletes. This single-arm observational study aimed to evaluate the effectiveness of a remotely delivered nutrition education program on sports nutrition knowledge and the dietary intake of junior elite triathletes (n = 21; female n = 9; male n = 12; 18.9 ± 1.6 y). A total of 18 participants completed dietary intake assessments (4-day food diary via Easy Diet DiaryTM) and 14 participants completed an 83-question sports nutrition knowledge assessment (Sports Nutrition Knowledge Questionnaire (SNKQ)) before and after the 8-week program. Sports nutrition knowledge scores improved by 15% (p < 0.001, ES = 0.9) following the program. Male participants reported higher energy intakes before (3348 kJ, 95% CI: 117−6579; p = 0.043) and after (3644 kJ, 95% CI: 451−6836; p = 0.028) the program compared to females. Carbohydrate intake at breakfast (p = 0.022), daily intakes of fruit (p = 0.033), dairy (p = 0.01) and calcium (p = 0.029) increased following nutrition education. Irrespective of gender, participants had higher intakes of energy (p < 0.001), carbohydrate (p = 0.001), protein (p = 0.007), and fat (p = 0.007) on heavy training days compared to lighter training days before and after the program with total nutrition knowledge scores negatively correlated with discretionary food intake (r = −0.695, p = 0.001). A remotely delivered nutrition education program by an accredited sports nutrition professional improved sports nutrition knowledge and subsequent dietary intake of junior elite triathletes, suggesting remote delivery of nutrition education may prove effective when social distancing requirements prevent face-to-face opportunities.

Effects of Dietary Intervention and Education on Selected Biochemical Parameters and Nutritional Habits of Young Soccer Players

In adolescence, the body requires sufficient amounts of adequate nutrients. This is especially important in the case of young athletes, for whom a nutrition plan should be as significant as a proper training plan. The aim of the study was a 17-week follow-up of the effects of individual and group nutrition intervention on changes in eating habits and selected biochemical parameters. 46 young soccer players aged 12–17 from the Soccer Academy in Northeastern Poland completed the study. One group received only individual recommendations, while the other additionally received group nutrition education. As a result of the dietary education, teenagers from the latter group consumed less saccharose (44 g vs. 39.2 g) in favor of digestible carbohydrates (266 g vs. 273 g) and dietary fiber (19.7 g vs. 22.2 g), further emphasizing the health-promoting profile of diets. The amount of fluid consumed (33% vs. 48% above 2 L of water a day) and the habits of the peri-workout hydration routine were also improved. Many of the participants (41%) reported faster regeneration while 26% experienced an overall better well-being. The short-term intervention produced positive results, but nevertheless it is the implementation of long-term dietary improvement schemes involving parents and coaches that should be the direction of future approaches.

Nutritional intakes of highly trained adolescent swimmers before, during, and after a national lockdown in the COVID-19 pandemic

Strict lockdown measures were introduced in response to the COVID-19 pandemic, which caused mass disruption to adolescent swimmers’ daily routines. To measure how lockdown impacted nutritional practices in this cohort, three-day photograph food diaries were analysed at three time points: before (January), during (April), and after (September) the first UK lockdown. Thirteen swimmers (aged 15 ± 1 years) from a high-performance swimming club submitted satisfactory food diaries at all time points. During lockdown, lower amounts of energy (45.3 ± 9.8 vs. 31.1 ± 7.7 kcal∙kg BM∙day^-1, p<0.001), carbohydrate (5.4 ± 1.2 vs. 3.5 ± 1.1 g∙kg BM∙day^-1, p<0.001), protein (2.3 ± 0.4 vs. 1.7 ± 0.4 g∙kg BM∙day^-1, p = 0.002), and fat (1.6 ± 0.4 vs. 1.1 ± 0.3 g∙kg BM∙day^-1, p = 0.011) were reported. After lockdown, no nutritional differences were found in comparison compared to before lockdown (energy: 44.0 ± 12.1 kcal∙kg BM∙day^-1; carbohydrate: 5.4 ± 1.4 g∙kg BM∙day^-1; protein: 2.1 ± 0.6 g∙kg BM∙day^-1; fat: 1.5 ± 0.6 g ∙kg BM∙day^-1, all p>0.05), despite fewer training hours being completed (15.0 ± 1.4 vs. 19.1 ± 2.2 h∙week^-1, p<0.001). These findings highlight the ability of adolescent swimmers to alter their nutrition based on their changing training circumstances when receiving sport nutrition support. However, some individuals displayed signs of suboptimal nutrition during lockdown that were not corrected once training resumed. This warrants future research to develop interactive education workshops that maintain focus and motivation towards optimal nutrition practices in isolated periods away from training.

Youth Athlete Development and Nutrition

Adolescence (ages 13–18 years) is a period of significant growth and physical development that includes changes in body composition, metabolic and hormonal fluctuations, maturation of organ systems, and establishment of nutrient deposits, which all may affect future health. In terms of nutrition, adolescence is also an important time in establishing an individual’s lifelong relationship with food, which is particularly important in terms of the connection between diet, exercise, and body image. The challenges of time management (e.g., school, training, work and social commitments) and periods of fluctuating emotions are also features of this period. In addition, an adolescent’s peers become increasingly powerful moderators of all behaviours, including eating. Adolescence is also a period of natural experimentation and this can extend to food choice. Adolescent experiences are not the same and individuals vary considerably in their behaviours. To ensure an adolescent athlete fulfils his/her potential, it is important that stakeholders involved in managing youth athletes emphasize eating patterns that align with and support sound physical, physiological and psychosocial development and are consistent with proven principles of sport nutrition.

Predisposing Risk Factors for Stress Fractures in Collegiate Cross-Country Runners

ABSTRACT

Giffin, KL, Knight, KB, Bass, MA, and Valliant, MW. Predisposing risk factors and stress fractures in collegiate cross-country runners. J Strength Cond Res 35(1): 227-232, 2021-The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross-country runners. Subjects in this study were 42 male and female cross-country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment using a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMDs) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of them did not meet the recommended daily energy intake or adequate intakes for calcium or vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in male and female runners whose daily calcium and vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of subjects (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.

Effects of Post-Exercise Whey Protein Consumption on Recovery Indices in Adolescent Swimmers

Purpose: This study examined the effect of whey protein consumption following high-intensity interval swimming (HIIS) on muscle damage, inflammatory cytokines and performance in adolescent swimmers. Methods: Fifty-four swimmers (11-17 years-old) were stratified by age, sex and body mass to a whey protein (PRO), isoenergetic carbohydrate (CHO) or a water/placebo (H₂O) group. Following baseline blood samples (06:00 h) and a standardised breakfast, participants performed a maximal 200 m swim, followed by HIIS. A total of two post-exercise boluses were consumed following HIIS and ~5 h post-baseline. Blood and 200 m performance measurements were repeated at 5 h, 8 h and 24 h from baseline. Muscle soreness was assessed at 24 h. Creatine kinase (CK), interleukin-6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-α) were measured in plasma. Results: No difference in 200 m swim performance was observed between groups. CK activity was elevated at 5 h compared to baseline and 24 h and at 8 h compared to all other timepoints, with no differences between groups. Muscle soreness was lower in PRO compared to H₂O (p = 0.04). Anti-inflammatory IL-10 increased at 8 h in PRO, while it decreased in CHO and H₂O. Conclusions: Post-exercise consumption of whey protein appears to have no additional benefit on recovery indices following HIIS compared to isoenergetic amounts of carbohydrate in adolescent swimmers. However, it may assist with the acute-inflammatory response.

Lessons for Local Policy Initiatives to Address Dietary Supplement Use Among Adolescents: A Qualitative Study of Stakeholders' Perceptions

PURPOSE

Weight-loss and muscle-building dietary supplements can have adverse health consequences for youth. At a time, when the Food and Drug Administration is considering increasing oversight of dietary supplements, this study aimed to explore community stakeholders' perceptions about the use of and access to such supplements among adolescents and to identify challenges and opportunities to engage stakeholders with policy initiatives to curtail youth access to supplements at the local level.

METHOD

We conducted 32 key informant semistructured interviews in four municipalities in Massachusetts with purposefully selected participants representing three categories of community stakeholders who could contribute to policy agenda setting at the local level: policy professionals, youth service providers, and young adults aged 18-25 years who used weight-loss or muscle-building supplements as minors. Interviews were audio-recorded, transcribed, deidentified, and analyzed using thematic analysis approach, facilitated by Dedoose software.

RESULTS

Community stakeholders reported wide availability and easy access to dietary supplements. Most participants were unaware of health risks. Many stakeholders did not perceive the use of these products as an issue impacting youth in their communities. The challenges identified in engaging stakeholders were competing concerns on the policy agenda, limited capacity of stakeholders, and uncertainty about who is accountable for the problem.

CONCLUSION

This study indicates the need for complementary, multipronged approaches at the municipal level to address the problem of weak regulation and easy access to potentially dangerous weight-loss and muscle-building supplements for youth.

Effects of post exercise protein supplementation on markers of bone turnover in adolescent swimmers

BACKGROUND

This study examined the effects of whey protein supplementation, compared with an isocaloric carbohydrate beverage and water, consumed immediately following an intense swimming trial on bone turnover in adolescent swimmers.

METHODS

Fifty-eight (31 female, 27 male) swimmers (14.1 ± 0.4 years) were stratified into three groups matched for age, sex and body mass. The protein and carbohydrate groups consumed two isocaloric post-exercise beverages each containing 0.3 g.kg- 1 of whey protein (with ~ 6 mg of calcium) or maltodextrin while the control group consumed water. Participants provided a morning, fasted, resting blood sample, then performed an intense swimming trial consisting of a maximal 200 m swim followed by a high intensity interval swimming protocol (5x100m, 5x50m and 5x25m; 1:1 work-to-rest ratio). Following swimming, they consumed their first respective post-exercise beverage, and 2 h later, they performed a second maximal swim immediately followed by the second beverage. Approximately 3 h after the second beverage, two post-consumption blood samples were collected at 8 h and 24 h from baseline. Procollagen type 1 intact N-terminal propeptide (PINP) and carboxy-terminal collagen crosslinks (CTXI) were measured in serum. The multiples of medians of PINP and CTXI were also used to calculate bone turnover rate and balance.

RESULTS

No significant changes were observed in PINP. CTXI increased (+ 11%) at 8 h in all groups, but then significantly decreased (- 22%) at 24 h in the protein group only. The protein group also had a significantly higher calculated rate of bone turnover at 8 h and 24 h compared to baseline, which was not observed in the other groups.

CONCLUSIONS

These results shed light on the potential importance of protein consumed shortly after intense swimming in promoting positive bone turnover responses up to 24 h following exercise in adolescent athletes.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov PRS; NCT04114045. Registered 1 October 2019 - Retrospectively registered.

Dietary nutrient intake of Korean adolescent distance runners

This study examined the dietary nutrient intake of Korean adolescent distance runners and analyzed the difference between weekdays and weekends. The participants were 40 male middle- and long-distance runners aged 13 to 18 years, 36 of whom were analyzed. The 3-day diet records including 2 weekdays and 1 weekend day, were investigated according to the food record method and analyzed using the computer-aided nutritional analysis program. A paired t-test was used to compare the energy and nutrient intakes of the weekdays and weekends, and the chi-square test was used to compare the distribution of the nutrient intake below the estimated average requirement. The results showed that the energy intake per day was quite low at 2,051.0±304.3 kcal, with a body mass index percentile of 16.8±9.8. The nutrients that showed remarkably lower levels than the dietary reference intakes for Koreans were vitamin D, vitamin C, vitamin B₂, and calcium, among which calcium was the highest at 86.1% in the proportion of those who consumed less than the estimated average requirement. The intakes of vitamin C and calcium, in particular, showed a significant decrease during the weekends. Therefore, to improve the dietary nutrient intake of adolescent male runners, appropriate management of the weekend diet as well as school meals should be considered.

Taking Stock of Dietary Supplements' Harmful Effects on Children, Adolescents, and Young Adults

PURPOSE

The aim of the study was to evaluate the relationship between supplement categories and adverse events in children, adolescents, and young adults.

METHODS

This is a retrospective observational study using adverse event reports between January 2004 and April 2015 in the U.S. Food and Drug Administration Adverse Event Reporting System on food and dietary supplements database. We quantified the relative risks for severe medical events of dietary supplements sold for various functions relative to vitamins among individuals aged between 0 and 25 years. Severe medical events include death, disability, life-threatening events, hospitalization, emergency room visit, and/or required intervention to prevent permanent disability.

RESULTS

There were 977 single-supplement-related adverse event reports affecting individuals aged between 0 and 25 years over 11 years (50.6% female; age: mean = 16.5 years, standard deviation = 7.5 years). Supplements sold for muscle building (risk ratio [RR] = 2.7; 95% confidence interval [CI] = 1.9-4.0), energy (RR = 2.6; 95% CI = 1.9-3.6), and weight loss (RR = 2.6; 95% CI = 1.9-3.4) were associated with almost three times the risk for severe medical events compared with vitamins.

CONCLUSIONS

Consumption of dietary supplements sold for weight loss, muscle building, and energy involved increased risks for severe medical events compared with vitamins. Proactive enforcement of regulations is needed to reduce access and consumption among children, adolescents, and young adults.

Correlates of health in adolescent elite athletes and adolescents: A cross-sectional study of 1016 adolescents

The primary aim of this cross-sectional study was to compare subjective correlates of health, such as nutrition, self-esteem, sleep and stress, between adolescent elite athletes (n = 625) and a reference group of adolescents (n = 391) not involved in elite sports. A secondary aim was to study predictors for self-perceived stress. A questionnaire was e-mailed to all participants containing valid questions about competence-based self-esteem, nutrition, self-perceived stress and sleep. Our results show that adolescent elite athletes reported significantly (p < .001) lower self-perceived stress, competence-based self-esteem, a more varied diet and more time of sleep, compared to adolescents not involved in elite sports (Hedges'g 0.31-0.82). Female adolescent elite athletes and female adolescents, compared to their male peer group, reported poorer values for competence-based self-esteem (elite, Hedges'g 0.29; adolescents, Hedges'g 0.30) and self-perceived stress (elite, Hedges'g 0.63; adolescents, Hedges'g 0.60). The linear mixed effect model revealed several significant (p < .05) predictors (sex, general well-being, competence-based self-esteem, sleep during weekdays, BMI, training volume) associated with self-perceived stress in adolescent elite athletes. In conclusion, differences in correlates of health with a moderate to strong effect sizes were found between the two groups, where elite athletes surprisingly reported less stress, competence-based self-esteem, a more varied diet and more time of sleep. Even if injury risk is high in adolescent elite athletes and pressure from multiple stakeholders is evident, it appears that the athletes still have better conditions for a good subjective health, based on self-reported measures, compared to adolescents not involved in elite sports.

The Dangerous Mix of Adolescents and Dietary Supplements for Weight Loss and Muscle Building: Legal Strategies for State Action

Adolescents use dietary supplements marketed for weight loss or muscle building, but these are not recommended by physicians. These products are often ineffective, adulterated, mislabeled, or have unclear dosing recommendations, and consumers have suffered injury and death as a consequence. When Congress passed the Dietary Supplement Health and Education Act, it stripped the Food and Drug Administration of its premarket authority, rendering regulatory controls too weak to adequately protect consumers. State government intervention is thus warranted. This article reviews studies reporting on Americans' use of dietary supplements marketed for weight loss or muscle building, notes the particular dangers these products pose to the youth, and suggests that states can build on their historical enactment of regulatory controls for products with potential health consequences to protect the public and especially young people from unsafe and mislabeled dietary supplements.

The impact of nutrition education on nutrition knowledge and adherence to the Mediterranean Diet in adolescent competitive swimmers

OBJECTIVES

Nutrition education of adolescent competitive swimmers is under-studied although their diet and nutrition knowledge are generally poor. This study aimed to assess the impact of nutrition education on nutrition knowledge and adherence to the Mediterranean Diet (MD) and explore the effect of parental education on the swimmers' MD adherence.

DESIGN

A pre-post measurement interventional study was carried out.

METHODS

A half-day nutrition education session was delivered for the swimmers and a separate session for their parents. At baseline and 6-weeks post-workshop, a short nutrition knowledge assessment of food sources of nutrients and the MD composition as well as adherence to the MD using the KIDMED Index were undertaken. The swimmers' parents also completed the KIDMED Index to evaluate the swimmers' diet.

RESULTS

Thirty-four competitive swimmers (age: 15.2±1.5 yr, 23 males) and 22 of their parents participated in the study. There was an improvement in MD adherence with 47% having good adherence post-intervention vs 21% at baseline (p<0.01) and an increase in the KIDMED Index score (median [interquartile range]: 5.0 [4.0-7.0] vs 7.0 [7.0-9.0]; p<0.01)). There was also an increase in the swimmers' nutrition knowledge assessment score (median [IQR]: 7.0 [5.0-8.0] vs 7.0 [6.0-8.0], p<0.05)), and a trend for a lower score post-intervention in swimmers whose parents did not participate compared to those whose parents participated (6.0 [6.0-7.8] vs 7.0 [7.0-8.0], p=0.063).

CONCLUSIONS

The intervention improved adherence to the MD and increased nutrition knowledge. The findings support parental participation in nutrition education.

Critical evaluation of food intake and energy balance in young modern pentathlon athletes: a cross-sectional study

BACKGROUND

Modern pentathlon comprises five sports: fencing, swimming, equestrian jumping, and a combined event of pistol shooting and running. Despite the expected high energy demand of this sport, there are few studies that provide support for the nutritional recommendations for pentathletes. The purpose of the present study was to evaluate young modern pentathlon athletes with respect to body composition, biochemical profile, and consumption of food and supplements.

METHODS

Fifty-six young modern pentathletes aged 13.5 ± 2.4 years participated in the study: 22 adolescent girls and 34 adolescent boys, weight 55.8 ± 13.3 kg, height 1.6 ± 0.1 m, and body fat 21.1 ± 3.1 %. Food consumption was analyzed through a 24-h recall method and food-frequency questionnaire. Assessment of body composition was carried out by checking anthropometric measures (body mass, height, and skinfolds) and using protocols according to participants' age and sexual maturity.

RESULTS

Male participants consumed less energy than the general recommendations for athletes from the American Dietetic Association (2749 ± 1024 kcal vs. 3113 ± 704 kcal, p < 0.01), whereas female participants consumed more energy than those recommendations (2558 ± 808 kcal vs. 2213 ± 4734 kcal, p < 0.01). Neither young men nor young women followed the carbohydrate intake recommendations for athletes (6.3 ± 2.5 g/kg/day and 6.6 ± 2.2 g/kg/day, respectively). Lipid and protein intakes corresponded to recommendations for both sexes; however, insufficient intakes of calcium, fruits, and vegetables were seen, as well as frequent consumption of baked goods and sugared soft drinks.

CONCLUSIONS

Adolescent modern pentathlon athletes presented inadequate eating habits with respect to consumption of carbohydrates and energy. Many participants had insufficient intake of micronutrients, especially calcium. However, future research is needed that is aimed at elucidating the real nutritional demands for good physical performance in this sport and the impact of inadequate eating habits on performance, especially among young athletes who are in the growth-stage years and are exposed to intense physical exercise routines.

The Preventive Effect of Calcium Supplementation on Weak Bones Caused by the Interaction of Exercise and Food Restriction in Young Female Rats During the Period from Acquiring Bone Mass to Maintaining Bone Mass

Increasing calcium (Ca) intake is important for female athletes with a risk of weak bone caused by inadequate food intake. The aim of the present study was to examine the preventive effect of Ca supplementation on low bone strength in young female athletes with inadequate food intake, using the rats as an experimental model. Seven-week-old female Sprague-Dawley rats were divided into four groups: the sedentary and ad libitum feeding group (SED), voluntary running exercise and ad libitum feeding group (EX), voluntary running exercise and 30% food restriction group (EX-FR), and a voluntary running exercise, 30% food-restricted and high-Ca diet group (EX-FR+Ca). To Ca supplementation, we used 1.2% Ca diet as "high-Ca diet" that contains two-fold Ca of normal Ca diet. The experiment lasted for 12 weeks. As a result, the energy availability, internal organ weight, bone strength, bone mineral density, and Ca absorption in the EX-FR group were significantly lower than those in the EX group. The bone strength and Ca absorption in the EX-FR+Ca group were significantly higher than those in the EX-FR group. However, the bone strength in the EX-FR+Ca group did not reach that in the EX group. These results suggested that Ca supplementation had a positive effect on bone strength, but the effect was not sufficient to prevent lower bone strength caused by food restriction in young female athletes.

Evaluation of congruence among dietary supplement use and motivation for supplementation in young, Canadian athletes

Background

Dietary supplement use is endemic in young athletes; however, it is unclear if their choices are congruent with their motivation for supplementation and the established benefits of the dietary supplements. The aim of this study was to evaluate the relationships between dietary supplement use and self-reported rationale in young athletes.

Methods

Canadian athletes (n = 567; 11–25 years; 76 % club or provincial level, 24 % national or higher) completed a questionnaire designed to assess supplementation patterns and motivation for supplementation. Chi square tests examined associations between dietary supplements and self-reported rationale for use.

Results

Vitamin and mineral supplements, including vitamin-enriched water, were associated with several health- and performance- related reasons (p < 0.001). Branched chain amino acids (BCAA) and glutamine were linked to improving diet and immune function (p < 0.01), but were more strongly associated with performance reasons, as were performance foods (protein powder, sport bars, sport gels, etc.). Plant extracts and fatty acids were primarily associated with health reasons, particularly immune support (p < 0.001).

Conclusions

Congruencies exist between performance rationales and supplementation for common ergogenic aids, however, less so for vitamin and mineral supplements, vitamin-enriched water, and plant extracts. Incongruences were found between fatty acids, protein supplements, vitamin and mineral supplements, vitamin-enriched water, and plant extracts and health motivators for supplementation. Educational interventions are essential to ensure young athletes are using dietary supplements safely and effectively.

Assessment of Energy Intake and Energy Expenditure of Male Adolescent Academy-Level Soccer Players during a Competitive Week

This study investigated the energy intake and expenditure of professional adolescent academy-level soccer players during a competitive week. Over a seven day period that included four training days, two rest days and a match day, energy intake (self-reported weighed food diary and 24-h recall) and expenditure (tri-axial accelerometry) were recorded in 10 male players from a professional English Premier League club. The mean macronutrient composition of the dietary intake was 318 ± 24 g·day⁻¹ (5.6 ± 0.4 g·kg⁻¹ BM) carbohydrate, 86 ± 10 g·day⁻¹ (1.5 ± 0.2 g·kg⁻¹ BM) protein and 70 ± 7 g·day⁻¹ (1.2 ± 0.1 g·kg⁻¹ BM) fats, representing 55% ± 3%, 16% ± 1%, and 29% ± 2% of mean daily energy intake respectively. A mean daily energy deficit of −1302 ± 1662 kJ (p = 0.035) was observed between energy intake (9395 ± 1344 kJ) and energy expenditure (10679 ± 1026 kJ). Match days (−2278 ± 2307 kJ, p = 0.012) and heavy training days (−2114 ± 2257 kJ, p = 0.016) elicited the greatest deficits between intake and expenditure. In conclusion, the mean daily energy intake of professional adolescent academy-level soccer players was lower than the energy expended during a competitive week. The magnitudes of these deficits were greatest on match and heavy training days. These findings may have both short and long term implications on the performance and physical development of adolescent soccer players.

Nutritional Considerations for Performance in Young Athletes

Nutrition is an integral component to any athletes training and performance program. In adults the balance between energy intake and energy demands is crucial in training, recovery, and performance. In young athletes the demands for training and performance remain but should be a secondary focus behind the demands associated with maintaining the proper growth and maturation. Research interventions imposing significant physiological loads and diet manipulation are limited in youth due to the ethical considerations related to potential negative impacts on the growth and maturation processes associated with younger individuals. This necessary limitation results in practitioners providing nutritional guidance to young athletes to rely on exercise nutrition recommendations intended for adults. While many of the recommendations can appropriately be repurposed for the younger athlete attention needs to be taken towards the differences in metabolic needs and physiological differences.

Sports Nutrition Advice for Adolescent Athletes

Adolescents participating in sport have high demands for nutritional adequacy to meet their needs for growth, development, wellness and athletics. Nutritional risk can be quite high in this population due to their unique needs, low access to credible information and nutrition professionals, and misinformation in the media and marketplace specifically targeting athletes. Physicians and other health professionals have an opportunity to communicate nutrition facts and make evidence-based recommendations about healthy eating in the setting of their ongoing interactions with adolescent athletes and their families. The purpose of this review is to describe the nutritional needs of adolescents participating in sport and highlight the potential for nutritional risk. Endorsed by professional organizations, our recommendations emphasize a balanced eating pattern that includes a wide variety of fresh, minimally processed whole foods. Our approach is to empower and teach adolescents to take responsibility for planning, preparing, and providing themselves consistent access to foods and fluids that deliver nutrients needed for proper fueling and recovery. Specific talking points that health professionals can use in brief interactions with patients and families are provided to endorse key behavioral strategies that young athletes can adopt to achieve peak athletic performance and optimal nutritional status.

Agreement between Two Methods of Dietary Data Collection in Male Adolescent Academy-Level Soccer Players

Collecting accurate and reliable nutritional data from adolescent populations is challenging, with current methods providing significant under-reporting. Therefore, the aim of the study was to determine the accuracy of a combined dietary data collection method (self-reported weighed food diary, supplemented with a 24-h recall) when compared to researcher observed energy intake in male adolescent soccer players. Twelve Academy players from an English Football League club participated in the study. Players attended a 12 h period in the laboratory (08:00 h–20:00 h), during which food and drink items were available and were consumed ad libitum. Food was also provided to consume at home between 20:00 h and 08:00 h the following morning under free-living conditions. To calculate the participant reported energy intake, food and drink items were weighed and recorded in a food diary by each participant, which was supplemented with information provided through a 24-h recall interview the following morning. Linear regression, limits of agreement (LOA) and typical error (coefficient of variation; CV) were used to quantify agreement between observer and participant reported 24-h energy intake. Difference between methods was assessed using a paired samples t-test. Participants systematically under-reported energy intake in comparison to that observed (p < 0.01) but the magnitude of this bias was small and consistent (mean bias = −88 kcal·day⁻¹, 95% CI for bias = −146 to −29 kcal·day⁻¹). For random error, the 95% LOA between methods ranged between −1.11 to 0.37 MJ·day⁻¹ (−256 to 88 kcal·day⁻¹). The standard error of the estimate was low, with a typical error between measurements of 3.1%. These data suggest that the combined dietary data collection method could be used interchangeably with the gold standard observed food intake technique in the population studied providing that appropriate adjustment is made for the systematic under-reporting common to such methods.

Hydration status and fluid intake of urban, underprivileged South African male adolescent soccer players during training

Background

Poor hydration compromises performance and heightens the risk of heat stress which adolescents are particularly susceptible to as they produce comparatively larger amount of metabolic heat during exercise. This study determined the hydration status and fluid intake of socio-economically disadvantaged, male adolescent soccer players during training.

Methods

A pilot study was conducted among 79 soccer players (mean age 15.9 ± 0.8 years; mean BMI 20.2 ± 2.1 kg/m²). Hydration status was determined before and after two training sessions, using both urine specific gravity and percent loss of body weight. The type and amount of fluid consumed was assessed during training. A self-administered questionnaire was used to determine the players’ knowledge regarding fluid and carbohydrate requirements for soccer training.

Results

Players were at risk of developing heat illness during six of the 14 training sessions (60 - 90 minutes in length). Although on average players were slightly dehydrated (1.023 ± 0.006 g/ml) before and after (1.024 ± 0.007 g/ml) training, some were extremely dehydrated before (24%) and after (27%) training. Conversely some were extremely hyperhydrated before (3%) and after training (6%). The mean percent loss of body weight was 0.7 ± 0.7%.

The majority did not consume fluid during the first (57.0%) and second (70.9%) training sessions. An average of 216.0 ± 140.0 ml of fluid was consumed during both training sessions. The majority (41.8%) consumed water, while a few (5.1%) consumed pure fruit juice. More than 90% stated that water was the most appropriate fluid to consume before, during and after training. Very few (5.0%) correctly stated that carbohydrate should be consumed before, during and after training.

Conclusions

Approximately a quarter were severely dehydrated. Many did not drink or drank insufficient amounts. The players’ beliefs regarding the importance of fluid and carbohydrate consumption did not correspond with their practices. A nutrition education programme is needed to educate players on the importance of fluid and carbohydrate to prevent dehydration and ensure appropriate carbohydrate intake.

Effect of milk consumption on rehydration in youth following exercise in the heat

Low-fat milk is thought to be an effective postexercise rehydration beverage in adults; however, little is known about milk’s rehydration ability in children after exercising in the heat. This study tested the hypothesis that because of its electrolyte and protein content, skim milk (SM) would be more effective than both water (W) and a carbohydrate/electrolyte solution (CES) in replacing body fluid losses in children following exercise in the heat. Thirty-eight (19 females) heat-acclimated pre- to early pubertal (PEP, aged 7–11 years) and mid- to late-pubertal (MLP, aged 14–17 years) children performed 3 sessions in 34.5 °C, 47.3% relative humidity, consisting of 2 × 20-min cycling bouts at 60% peak oxygen uptake followed by consumption of either W, CES, or SM. Each beverage was consumed immediately after exercise in a volume equal to 100% of their body mass loss during exercise. Urine samples were collected before, during, and after exercise, as well as the 2-h period following beverage consumption. On average, children dehydrated 1.3% ± 0.4%. Children ingested 0.40 ± 0.11 L (PEP) and 0.74 ± 0.20 L (MLP) of fluid. The fraction of the ingested beverage retained at 2 h of recovery was greater with SM (74% ± 18%) than W (47% ± 26%) and CES (59% ± 20%, p < 0.001 for both), and greater in CES than W (p < 0.001). All participants were in a hypohydrated state after 2 h of recovery, following the pattern SM < CES < W. In both PEP and MLP children, SM is more effective than W and CES at replacing fluid losses that occur during exercise in the heat.

Nutritional knowledge of UK coaches

Athletes obtain nutritional information from their coaches, yet their competency in this area is lacking. Currently, no research exists in the UK which has a different coach education system to many other countries. Therefore, the aim of this study was to evaluate the sports nutrition knowledge of UK coaching certificate (UKCC) level 2 and 3, hockey and netball qualified coaches. All coaches (n = 163) completed a sports nutrition questionnaire to identify: (a) if they provided nutritional advice; (b) their level of sport nutrition knowledge; and (c) factors that may have contributed to their level of knowledge. Over half the coaches provided advice to their athletes (n = 93, 57.1%), even though they were not competent to do so. Coaches responded correctly to 60.3 ± 10.5% of all knowledge questions with no differences between those providing advice and those who did not (p > 0.05). Those coaches who had undertaken formal nutrition training achieved higher scores than those who had not (p < 0.05). In conclusion, UK sports coaches would benefit from continued professional development in sports nutrition to enhance their coaching practice.

Higher incidence of bone stress injuries with increasing female athlete triad-related risk factors: a prospective multisite study of exercising girls and women

BACKGROUND

Identifying the risk factors associated with a bone stress injury (BSI), including stress reactions and stress fractures, may aid in targeting those at increased risk and in formulating prevention guidelines for exercising girls and women.

PURPOSE

To evaluate the effect of single or combined risk factors as defined by the female athlete triad-a syndrome involving 3 interrelated spectrums consisting of energy availability, menstrual function, and bone mass-with the incidence of BSIs in a multicenter prospective sample of 4 cohorts of physically active girls and women.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

At baseline, participants' (N = 259; mean age, 18.1 ± 0.3 years) anthropometric characteristics, eating attitudes and behaviors, menstrual function, sports participation or exercise activity, and pathological weight control behaviors were assessed. Dual-energy x-ray absorptiometry (DXA) measured the bone mass of the whole body, total hip, femoral neck, lumbar spine, and body composition. Participants were followed prospectively for the occurrence of injuries; those injuries confirmed by a physician were recorded.

RESULTS

Twenty-eight participants (10.8%) incurred a BSI. Forty-six percent of those who had ≥12 h/wk of purposeful exercise, a bone mineral density (BMD) Z score <-1.0, and who exhibited 3 to 4 of the following: BMI <21.0 kg/m2, oligo- or amenorrhea, elevated dietary restraint, and/or participation in a leanness sport exercise/activity at baseline, incurred a BSI during the prospective study period. Single factors significantly (P < .05) associated with the development of a BSI included ≥12 h/wk of purposeful exercise (14.7%), BMI <21.0 kg/m2 (15.3%), and low bone mass (BMD Z score <-1.0; 21.0%). The strongest 2- and 3-variable combined risk factors were low BMD (Z score <-1.0) + ≥12 h/wk of exercise, with 29.7% incurring a BSI (odds ratio [OR], 5.1; 95% CI, 2.2-12.1), and ≥12 h/wk of exercise + leanness sport/activity + dietary restraint, with 46.2% incurring a BSI (OR, 8.7; 95% CI, 2.7-28.3).

CONCLUSION

In the sample, which included female adolescents and young adults participating in competitive or recreational exercise activities, the risk of BSIs increased from approximately 15% to 20% for significant single risk factors to 30% to 50% for significant combined female athlete triad-related risk factor variables. These data support the notion that the cumulative risk for BSIs increases as the number of Triad-related risk factors accumulates.

Sport nutrition for young athletes

Nutrition is an important part of sport performance for young athletes, in addition to allowing for optimal growth and development. Macronutrients, micronutrients and fluids in the proper amounts are essential to provide energy for growth and activity. To optimize performance, young athletes need to learn what, when and how to eat and drink before, during and after activity.

Sports drink consumption and diet of children involved in organized sport

BACKGROUND

Organized sport provides one option for children to be physically active. However, there is a paucity of information about the relationship between children's participation in organized sport and their diet, and specifically their sports drink consumption. Therefore, the relationship between sports participation in children and the consumption of sports drinks, sugar-sweetened beverages (SSBs) and other components of diet was examined.

METHODS

A cross-sectional descriptive study was conducted using baseline data from the Action Schools! BC Dissemination study cohort (n = 1421; 9.90 (0.58) y; 736 girls, 685 boys). The differences between the dietary behaviours of children participating in organized sport (sport) versus those that did not participate (non-sport) was examined. A modified Physical Activity Questionnaire for Older Children (PAQ-C) was used to measure physical activity levels and participation in organized sport. A Food Frequency Questionnaire (FFQ) and 24-hour dietary recall were used to assess eating behaviour and macronutrient intake (including protein, fat, and carbohydrate as well as sugar, fibre and total calories). Fruit, vegetable and beverage quantities were hand-tallied from the dietary recall. Fruit, vegetable and beverage frequency was assessed using the FFQ. Analysis of covariance (ANCOVA) was used to analyse differences between groups and a chi-square test of association was use to determine if participation in sport was significantly associated with the proportion of children consuming sports drinks and SSBs, and with gender.

RESULTS

Children involved in sport had a lower body mass index (BMI) and were more physically active than children in the non-sport group (p < 0.01). Only a small number (n = 20/1421) of children consumed sports drinks and no difference in consumption of sports drink between sport and non-sport participants (p > .05) was observed. However, children involved in organized sport consumed more total calories, fat, fibre, fruit, vegetables and non-flavoured milk (p < 0.01) than non-sport children.

CONCLUSIONS

Children involved in organized sport were more physically active, consumed a healthier diet than non-participants and on average had lower BMI's despite consuming more calories. As consumption of sports drinks among this age group was low, this may be an ideal time to begin educating children and their parents about the appropriate consumption of sports drinks and the perils of consuming too many SSBs, specifically.

Carbohydrate supplementation and prolonged intermittent high-intensity exercise in adolescents: research findings, ethical issues and suggestions for the future

In the last decade, research has begun to investigate the efficacy of carbohydrate supplementation for improving aspects of physical capacity and skill performance during sport-specific exercise in adolescent team games players. This research remains in its infancy, and further study would be beneficial considering the large youth population actively involved in team games. Literature on the influence of carbohydrate supplementation on skill performance is scarce, limited to shooting accuracy in adolescent basketball players and conflicting in its findings. Between-study differences in the exercise protocol, volume of fluid and carbohydrate consumed, use of prior fatiguing exercise and timing of skill tests may contribute to the different findings. Conversely, initial data supports carbohydrate supplementation in solution and gel form for improving intermittent endurance running capacity following soccer-specific shuttle running. These studies produced reliable data, but were subject to limitations including lack of quantification of the metabolic response of participants, limited generalization of data due to narrow participant age and maturation ranges, use of males and females within the same sample and non-standardized pre-exercise nutritional status between participants. There is a lack of consensus regarding the influence of frequently consuming carbohydrate-containing products on tooth enamel erosion and the development of obesity or being overweight in adolescent athletes and non-athletes. These discrepancies mean that the initiation or exacerbation of health issues due to frequent consumption of carbohydrate-containing products by adolescents cannot be conclusively refuted. Coupled with the knowledge that consuming a natural, high-carbohydrate diet -3-8 hours before exercise can significantly alter substrate use and improve exercise performance in adults, a moral and ethical concern is raised regarding the direction of future research in order to further knowledge while safeguarding the health and well-being of young participants. It could be deemed unethical to continue study into carbohydrate supplementation while ignoring the potential health concerns and the possibility of generating similar performance enhancements using natural dietary interventions. Therefore, future work should investigate the influence of pre-exercise dietary intake on the prolonged intermittent, high-intensity exercise performance of adolescents. This would enable quantification of whether pre-exercise nutrition can modulate exercise performance and, if so, the optimum dietary composition to achieve this. Research could then combine this knowledge with ingestion of carbohydrate-containing products during exercise to facilitate ethical and healthy nutritional guidelines for enhancing the exercise performance of adolescents. This article addresses the available evidence regarding carbohydrate supplementation and prolonged intermittent, high-intensity exercise in adolescent team games players. It discusses the potential health concerns associated with the frequent use of carbohydrate-containing products by adolescents and how this affects the research ethics of the field, and considers directions for future work.

Fluid Balance and Dehydration in the Young Athlete

Many young athletes train and compete under conditions that put their body fluid balance at risk, and hypohydration is usually the major concern. Another less frequent condition is hyperhydration that—if accompanied by other risk factors—may cause hyponatremia. Water and electrolyte losses during physical activities occur primarily from sweat. Such losses have been identified mostly in active (but nonathletic) young populations under laboratory settings. Studies have been trying to estimate fluid losses in the athletic population under field conditions, taking into account the sport modality and environmental conditions. Besides these external conditions, young athletes adopt different drinking attitudes, which may depend on knowledge, education, and the opportunities to drink during the break periods as well as fluid availability. Focusing on the young athlete, this review will discuss water and sodium losses from sweat, the effects of hypohydration on performance, and fluid intake attitudes within and during practices and competitions. Some considerations related to the methods of identifying hydration status and guidelines are also given, with the understanding that they should be individually adapted for the athlete and activity. The young athlete, parents, coaches, and athletic/health professionals should be aware of such information to prevent fluid imbalances and the consequent hazardous effects on performance and health.

Comparison of nutritional intake in US adolescent swimmers and non-athletes

Swimming is a very popular sport among adolescents in the US. Little is known about the diet of competitive adolescent swimmers in the US but data from other countries indicate several inadequacies, including excessive intake of fat and lower than recommended intake of carbohydrate and several micronutrients that may affect athletic performance and bone accrual. We assessed usual diet, using a food frequency questionnaire and calcium checklist, among 191 adolescent males and females [91 swimmers (mean 13.7, s = 2.5 years) and 100 non-athletes (mean 14.4, s = 2.8 years)]. For both males and females, swimmers and non-athletes generally had similar average intakes of macro- and micro-nutrients, including higher than recommended amounts of total fat (36%) and saturated fat (12%), and inadequate amounts of calcium, vitamin D, and daily servings of fruits, vegetables, grains, and dairy products. This first study of nutritional intake among adolescent swimmers in the US suggests that dietary habits of adolescents who swim competitively may jeopardize optimal athletic performance and place them at risk for future chronic diseases, including osteoporosis.

Energy and macronutrient intake in adolescent sprint athletes: a follow-up study

Macronutrient intake, height, weight, and body composition of 60 adolescent sprint athletes were estimated every 6 months over 3 years. Seven-day food records were analysed based on the Belgian and Dutch food databanks. The age of participants at the start of the 3-year study was 14.8 ± 1.6 years for female athletes and 14.7 ± 1.9 years for male athletes. Girls and boys gained height (3.4 ± 4.6 cm and 5.9 ± 6.6 cm respectively) and weight (5.6 ± 3.5 kg and 8.7 ± 5.5 kg respectively), whereas percent body fat remained unchanged in both girls and boys (around 17.0% and 8.5% respectively). Mean protein intake of around 1.5 g · kg⁻¹ body weight was within recommendations on each occasion for both sexes. Carbohydrate intakes between 5 and 7 g · kg⁻¹ body weight support a training programme of moderate intensity. Total and saturated fat intakes were high at the start of the study (girls: 31.8 ± 3.5% and 12.2 ± 2.0% of energy intake; boys: 30.3 ± 4.6% and 12.0 ± 1.9% of energy intake) and it appeared to be difficult to achieve and maintain lower intakes. Consistent low fluid intakes around 40 ml · kg⁻¹ body weight were observed. General non-stringent advice for improvement of the diet resulted in significant favourable changes only for the consumption of wholegrain bread, vegetables, and soft drinks. Dietary habits of adolescent sprint athletes are not always according to guidelines and are relatively stable but repeated advice can induce moderate improvements.

Dietary acid-base balance in adolescent sprint athletes: a follow-up study

Sprinters are advised to include additional protein sources in their diet. Basal metabolism and vigorous physical activities generate hydrogen ions that need to be buffered. The present follow-up study estimates the dietary potential renal acid load (PRAL) and net endogenous acid production (NEAP) in adolescent sprint athletes. Seven-day food diaries and anthropometrics of 60 adolescent sprint athletes (mean age at start 14.7 ± 1.9 years) were collected every six months over a three year period. Comparisons were made between athletes with a negative (PRAL(−)) versus positive PRAL (PRAL(+)). For the entire sample, mean PRAL values of up to 6 mEq/day were slightly positive despite a relatively high protein intake of around 1.5 g/kg. The NEAP ranging between 42 and 46 mEq/day remained stable during the study period. Athletes with a PRAL(−) (−8 to −10 mEq/day) consumed significantly more fruit and fruit juice than athletes with a PRAL(+) (+9 to 14 mEq/day). Athletes with a PRAL(+) did not consume more meat, fish and poultry than athletes with a PRAL(−). Grains and dairy products were only discriminative between the two groups on one measurement occasion. Lowering the PRAL can be obtained by increasing the consumption of potatoes, fruits, vegetables and vegetable soup.