Risk of low energy availability, eating disorders and food insecurity amongst development female rugby league players.

BACKGROUND: There have been several published studies on the prevalence of low energy availability (LEA) risk amongst North American and European endurance athletes. Yet the prevalence and risk factors amongst rugby league players are less well understood. This study assessed the prevalence of low energy availability risk, eating disorder risk, and food security amongst players from a female National Rugby League squad in Australia. METHODS: Players from one Australian professional rugby league club volunteered to participate in the study. An online questionnaire was conducted to determine the prevalence of low energy availability (Low Energy Availability in Females Questionnaire [LEAF-Q]), eating disorder risk (Eating Disorders Inventory [EDI-3]), and food security. RESULTS: Differences between those "at risk" and "not at risk" based on their total LEAF-Q score were determined. Of the 28 players, 64% (N.=18) were at risk of LEA. Raw scores for the EDI-3 subscales, body dissatisfaction (P=0.043), bulimia (P=0.002), composite score (P=0.038), were significantly higher for those at risk and not at risk of LEA. Forty percent of players had some level of food insecurity. CONCLUSIONS: The results suggest LEA risk is similar to other populations and those at risk of LEA are more likely to have an elevated clinical risk of eating disorders. Food security is also an issue in this population and could contribute to LEA risk for some. Future research is needed amongst team sports athletes to understand interplay between eating disorder risk and food insecurity with LEA risk.

Risk of low energy availability and nutrition knowledge among female team sport athletes.

BACKGROUND: Nutrition knowledge influences adequate dietary intake in athletes. Inadequate dietary intakes can result in low energy availability (LEA) which can lead to relative energy deficiency in sport (RED-S). To date, there is little information on the relationship between nutrition knowledge and the risk of LEA in female team sport athletes. This study investigates if general and sports nutrition knowledge are associated with the risk of LEA in female team athletes. METHODS: A cross-sectional design was used. Female athletes (>16 years) who participate in team sports in New Zealand were asked to complete an online questionnaire. The LEA in Females Questionnaire and the Abridged Sport Nutrition Knowledge Questionnaire were included. LEA risk and general/sports nutrition knowledge were assessed. The relationship between LEA risk and knowledge was analyzed using the Kruskal-Wallis Test of independent variables and χ2 tests. RESULTS: Among 100 female athletes, 53% were at-risk for LEA, and 70% (N.=67) had poor nutrition knowledge. Athletes who were "at-risk" for LEA and those who were "not at-risk" for LEA did not differ statistically in terms of age (P=0.350) or BMI (P=0.576). Of those "not at risk" 54% had an A-NSK score between 50 and 60% (i.e., average knowledge), whereas 54% of the athletes who were "at risk" for LEA had poor nutrition knowledge. There was no statistical difference between the groups (P=0.273). CONCLUSIONS: The poor nutrition knowledge and the high rates of those "at risk" of LEA among team sports athletes indicates the need for more nutrition education in this population.

Dietary energy intake across the menstrual cycle: a narrative review.

Females are often underrepresented in the scientific literature, but awareness of the need for female-specific research is increasing. Review articles have been published on the effects of the menstrual cycle on aspects of exercise performance and physiology, yet to date no research has reviewed the effect of menstrual cycle phase on dietary energy intake. Fluctuations in endogenous sex hormones across the menstrual cycle influence a range of physiological processes, including those involved in nutritional status. Observational research typically quantifies female athletes' nutritional intakes at a single time point; however, this may provide inaccurate information if dietary intake fluctuates across the menstrual cycle. Similarly, this may have implications for interventional research, where dietary intake is often poorly controlled or monitored. This review aimed to synthesize the published literature on dietary energy intakes of naturally menstruating females in various phases of the menstrual cycle. The review critiques the relevant literature in light of recent publications on good practice for female research, explores the impact of the menstrual cycle on energy intake, identifies gaps within the evidence base, and informs future research. Overall, energy intake appears to be lower in the follicular phase compared with the luteal phase, with a particular decrease in the days leading up to and including ovulation. The magnitude of these fluctuations is not yet clearly quantifiable and most likely varies, both between individuals, and from cycle to cycle. This review notes the lack of high-quality research investigating the energy intakes of females across the menstrual cycle, and the very limited data available for female athletes and others who undertake large amounts of physical activity. It also highlights the need for researchers to take into consideration anovulatory cycles and the potential effects of premenstrual disorders on dietary intake.

The development and validation of a questionnaire to assess relative energy deficiency in sport (RED-S) knowledge.

OBJECTIVES: The aim of this study was to develop and validate a questionnaire assessing knowledge of signs and symptoms of relative energy deficiency in sport among healthcareprofessionals and physically active individuals. DESIGN: Cross-sectional study. METHODS: The questionnaire was created in two phases: 1)Item development was established through a literature review, expert review (n = 4), and pre-testing among healthcare professionals, dietetic students, and the general population (n = 35). 2) Validity (item analysis, construct validity) and internal reliability were assessed by administrating the questionnaire to healthcare professionals (n = 97) and physically active individuals who engaged in moderate to intense physical activity (n=77). The questionnaire was re-administered in a subset of the same groups (n = 88) for test-retest reliability. RESULTS: The expert responses showed >80% acceptability and pretesting through interviews indicated good content and face validity. Item response analysis resulted in removal of 6 items due to low discrimination ability. Significantly higher knowledge scores in health professionals compared with non-health professionals (mean difference (95% CI) = 2.8 (1.9, 3.7)) confirmed construct validity. Internal consistency, assessed using Cronbach's alpha (α = 0.79), and test-retest reliability using intra-class correlation coefficients (intra-class correlation coefficients = 0.80; Spearman's correlation = 0.84, p < 0.001) were good. The final questionnaire had 18 items assessing knowledge of signs and symptoms of Relative Energy Deficiency in Sport. CONCLUSIONS: The questionnaire provides a valid and reliable tool to assess knowledge of signs and symptoms of Relative Energy Deficiency in Sport among health professionals and physically active individuals, which could guide future education requirements by assessing current knowledge.

Endothelial-Specific Loss of Sphingosine-1-Phosphate Receptor 1 Increases Vascular Permeability and Exacerbates Bleomycin-induced Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease which leads to significant morbidity and mortality from respiratory failure. The two drugs currently approved for clinical use slow the rate of decline in lung function but have not been shown to halt disease progression or reverse established fibrosis. Thus, new therapeutic targets are needed. Endothelial injury and the resultant vascular permeability are critical components in the response to tissue injury and are present in patients with IPF. However, it remains unclear how vascular permeability affects lung repair and fibrosis following injury. Lipid mediators such as sphingosine-1-phosphate (S1P) are known to regulate multiple homeostatic processes in the lung including vascular permeability. We demonstrate that endothelial cell-(EC) specific deletion of the S1P receptor 1 (S1PR1) in mice (EC-S1pr1-/-) results in increased lung vascular permeability at baseline. Following a low-dose intratracheal bleomycin challenge, EC-S1pr1-/- mice had increased and persistent vascular permeability compared with wild-type mice, which was strongly correlated with the amount and localization of resulting pulmonary fibrosis. EC-S1pr1-/- mice also had increased immune cell infiltration and activation of the coagulation cascade within the lung. However, increased circulating S1P ligand in ApoM-overexpressing mice was insufficient to protect against bleomycin-induced pulmonary fibrosis. Overall, these data demonstrate that endothelial cell S1PR1 controls vascular permeability in the lung, is associated with changes in immune cell infiltration and extravascular coagulation, and modulates the fibrotic response to lung injury.

Relationships between Dietary Patterns and Indices of Arterial Stiffness and Central Arterial Wave Reflection in 9-11-Year-Old Children.

Arterial stiffness is an important marker of vascular damage and a strong predictor of cardiovascular diseases (CVD). Given that pathophysiological processes leading to an increased arterial stiffness begin during childhood, the aim of this clustered observational study was to determine the relationship between modifiable factors including dietary patterns and indices of aortic arterial stiffness and wave reflection in 9-11-year-old children. Data collection was conducted between April and December 2015 in 17 primary schools in Dunedin, New Zealand. Dietary data were collected using a previously validated food frequency questionnaire and identified using principal component analysis method. Arterial stiffness (carotid-femoral pulse wave velocity, PWV) and central arterial wave reflection (augmentation index, AIx) were measured using the SphygmoCor XCEL system (Atcor Medical, Sydney, Australia). Complete data for PWV and AIx analyses were available for 389 and 337 children, respectively. The mean age of children was 9.7 ± 0.7 years, 49.0% were girls and 76.0% were classified as "normal weight". The two identified dietary patterns were "Snacks" and "Fruit and Vegetables". Mean PWV and AIx were 5.8 ± 0.8 m/s and -2.1 ± 14.1%, respectively. There were no clinically meaningful relationships between the identified dietary pattern scores and either PWV or AIx in 9-11-year-old children.

Hepcidin and iron: novel findings for elite female rugby Sevens players.

BACKGROUND: Iron deficiency is a common deficiency disease worldwide with athletes at increased risk. METHODS: A proposed new mechanism of exercise-induced iron deficiency in athletes involves the iron-regulatory hormone hepcidin, however, there is limited information on this amongst elite athletes. This study describes iron status in elite female rugby Sevens players. RESULTS: Blood samples were collected at the start and mid-season and analyzed for serum iron, serum ferritin (SF), soluble transferring receptor (sTfR), high sensitivity C-reactive Protein (hsCRP) and hepcidin. Of the 17 players 18% were iron deficient (SF<30 µg/L) with 29-35% of players with sub-optimal iron stores at some point during the study (SF<45 µg/L). Serum hepcidin was strongly correlated with SF (r=0.61, P=0.0001). CONCLUSIONS: Some elite female rugby Sevens players have sub-optimal iron stores over the course of a season.

Dietary Intakes Differ by Body Composition Goals: An Observational Study of Professional Rugby Union Players in New Zealand.

Preseason in rugby union is a period of intensive training where players undergo conditioning to prepare for the competitive season. In some cases, this includes modifying body composition through weight gain or fat loss. This study aimed to describe the macronutrient intakes of professional rugby union players during pre-season training. It was hypothesized that players required to gain weight would have a higher energy, carbohydrate and protein intake compared to those needing to lose weight. Twenty-three professional rugby players completed 3 days of dietary assessment and their sum of eight skinfolds were assessed. Players were divided into three groups by the team coaches and medical staff: weight gain, weight maintain and weight loss. Mean energy intakes were 3,875 ± 907 kcal·d-1 (15,965 ± 3,737 kJ·d-1) (weight gain 4,532 ± 804 kcal·d-1; weight maintain 3,825 ± 803 kcal·d-1; weight loss 3,066 ± 407 kcal·d-1) and carbohydrate intakes were 3.7 ± 1.2 g·kg-1·d-1 (weight gain 4.8 ± 0.9 g.kg-1·d-1; weight maintain 2.8 ± 0.7 g·kg-1·d-1; weight loss 2. 6 ± 0.7 g·kg-1·d-1). The energy and carbohydrate intakes are similar to published intakes among rugby union players. There were significant differences in energy intake and the percent of energy from protein between the weight gain and the weight loss group.

Hepcidin as a Prospective Individualized Biomarker for Individuals at Risk of Low Energy Availability.

Hepcidin, a peptide hormone with an acknowledged evolutionary function in iron homeostasis, was discovered at the turn of the 21st century. Since then, the implications of increased hepcidin activity have been investigated as a potential advocate for the increased risk of iron deficiency in various health settings. Such implications are particularly relevant in the sporting community where peaks in hepcidin postexercise (∼3-6 hr) are suggested to reduce iron absorption and recycling, and contribute to the development of exercise-induced iron deficiency in athletes. Over the last decade, hepcidin research in sport has focused on acute and chronic hepcidin activity following single and repeated training blocks. This research has led to investigations examining possible methods to attenuate postexercise hepcidin expression through dietary interventions. The majority of macronutrient dietary interventions have focused on manipulating the carbohydrate content of the diet in an attempt to determine the health of athletes adopting the low-carbohydrate or ketogenic diets, a practice that is a growing trend among endurance athletes. During the process of these macronutrient dietary intervention studies, an observable coincidence of increased cumulative hepcidin activity to low energy availability has emerged. Therefore, this review aims to summarize the existing literature on nutritional interventions on hepcidin activity, thus, highlighting the link of hepcidin to energy availability, while also making a case for the use of hepcidin as an individualized biomarker for low energy availability in males and females.

Dietary Patterns, Cardiorespiratory and Muscular Fitness in 9⁻11-Year-Old Children from Dunedin, New Zealand.

Research shows that cardiorespiratory (CRF) and muscular fitness in childhood are associated with a healthier cardiovascular profile in adulthood. Identifying factors associated with measures of fitness in childhood could allow for strategies to optimize cardiovascular health throughout the lifecourse. The aim of this study was to examine the association between dietary patterns and both CRF and muscular fitness in 9⁻11-year-olds. In this study of 398 children, CRF and muscular fitness were assessed using a 20-m shuttle run test and digital hand dynamometer, respectively. Dietary patterns were derived using principal component analysis. Mixed effects linear regression models were used to assess associations between dietary patterns and CRF and muscular fitness. Most children had healthy CRF (99%, FITNESSGRAM) and mean ± SD muscular fitness was 15.2 ± 3.3 kg. Two dietary patterns were identified; “Snacks” and “Fruit and Vegetables”. There were no significant associations between either of the dietary patterns and CRF. Statistically significant but not clinically meaningful associations were seen between dietary patterns and muscular fitness. In an almost exclusively fit cohort, food choice is not meaningfully related to measures of fitness. Further research to investigate diet-fitness relationships in children with lower fitness levels can identify key populations for potential investments in health-promoting behaviors.

Physiological responses to a five-day adventure race: Continuous blood glucose, hemodynamics and metabolites the 2012 GODZone field-study.

BACKGROUND/OBJECTIVE: Adventure racing is an ultra-endurance activity that imposes a unique multifaceted stress on the human body. The purpose of this field study was to examine the physiological responses to a 5-day adventure race. METHODS: Eight competitors, two teams (1 female each) in the 2012 GODZone adventure race volunteered. Competitors trekked, cycled and paddled ∼326 km in ∼116 hours. Continuous glucose was measured the day before and throughout. Body mass, urinary solutes, and blood pressure and heart rate during resting, standing, and repeated squat-stand conditions, were assessed pre and post. RESULTS: Despite no changes in mean blood glucose levels, there was increased glycemic variability (Standard deviation glucose; Pre: 0.5 ±â€¯0.1 vs Race: 1.0 ±â€¯0.2 mmol/L, p = 0.02) and periods of hypoglycemia (i.e., Min glucose Pre: 4.1 ±â€¯0.3 vs Race: 3.6 ±â€¯0.5 mmol/L, p = 0.05) during the race. After the race, the blood pressure during resting, standing and squat-stand conditions was significantly lower, by 14 ±â€¯14 mmHg, 16 ±â€¯15 mmHg and 18 ±â€¯15 mmHg (all p < 0.05), respectively, with no change in heart rate. During five-days of adventure racing there is increased glycemic variability and more frequent periods of low blood glucose levels. Additionally, following the race pronounced hypotension is observed in competitors. CONCLUSION: We observed more frequent glucose fluctuations, lower glucose levels and significant perturbations in blood pressure control. Further research is warranted to examine the long-term impact of adventure racing on metabolic and cardiovascular function.

ß-Hydroxy ß-Methylbutyrate (HMB) Supplementation Effects on Body Mass and Performance in Elite Male Rugby Union Players.

McIntosh, ND, Love, TD, Haszard, J, Osborne, H, and Black, KE. ß-hydroxy ß-methylbutyrate (HMB) supplementation effects on body mass and performance in elite male rugby union players. J Strength Cond Res 32(1): 19-26, 2018-Preseason is characterized by high training volumes with short recovery periods ß-hydroxy ß-methylbutyrate (HMB) has been postulated to assist with recovery. ß-hydroxy ß-methylbutyrate has been shown to improve strength and body composition among untrained groups; the benefits of HMB among trained populations are unclear because of the methodologies employed. This randomized control trail determined the effects of 11 weeks HMB supplementation on body mass and performance measures in 27 elite rugby players. ß-hydroxy ß-methylbutyrate group (n = 13), mean ± SD age 20.3 ± 1.2 years, body mass 99.6 ± 9.1 kg; placebo group (n = 14), age 21.9 ± 2.8 years body mass 99.4 ± 13.9 kg for placebo. During the supplementation period, body mass increased with HMB 0.57 ± 2.60 kg but decreased with placebo 1.39 ± 2.02 kg (p = 0.029). There were no significant differences in any of the 4 strength variables (p > 0.05). However, on the yo-yo intermittent recovery test (YoYo IR-1), the placebo group improved 4.0 ± 2.8 levels but HMB decreased 2.0 ± 3.0 levels (p = 0.003). The results of this study suggest that HMB could be beneficial for gaining or maintaining body mass during periods of increased training load. However, it appears that HMB may be detrimental to intermittent running ability in this group although further research is required before firm conclusions can be made. Only 6 participants on HMB managed to complete both YoYo IR-1 tests because of injury, a larger sample size is required to fully investigate this potentially negative effect. Further, the mechanisms behind this decrement in performance cannot be fully explained and requires further biochemical and psychological investigation.

Sleep timing is associated with diet and physical activity levels in 9-11-year-old children from Dunedin, New Zealand: the PEDALS study.

It is well documented that short sleep duration is associated with excess body weight and poor food intake in children. It has been suggested that sleep timing behaviour may also be an important predictor of weight and other related behaviours, independent of sleep duration; however, there is a lack of research investigating these relationships. The present study investigated sleep timing in association with diet and physical activity levels in 439 children aged 9-11 years old from New Zealand. Sleep and physical activity data were collected using accelerometry, and food choice using a short food-frequency questionnaire. Participants were classified into one of four sleep timing behaviour categories using the median split for sleep-onset and -offset times. Differences between sleep timing groups for weekly consumption frequency of selected food groups, dietary pattern scores and minutes of moderate-to-vigorous physical activity were examined. Children in the late sleep/late wake category had a lower 'Fruit & Vegetables' pattern score [mean difference (95% CI): -0.3 (-0.5, -0.1)], a lower consumption frequency of fruit and vegetables [mean weekly difference (95% CI): -2.9 (-4.9, -0.9)] and a higher consumption frequency of sweetened beverages [mean weekly difference (95% CI): 1.8 (0.2, 3.3)] compared with those in the early sleep/early wake category. Additionally, children in the late sleep/late wake category accumulated fewer minutes of moderate-to-vigorous physical activity per day compared with those in the early sleep/early wake category [mean difference (95% CI): -9.4 (-15.3, -3.5)]. These findings indicate that sleep timing, even after controlling for sleep duration, was associated with both food consumption and physical activity.

Cardiorespiratory fitness is positively associated with a healthy dietary pattern in New Zealand adolescents.

OBJECTIVE: To examine the association between cardiorespiratory fitness and dietary patterns in adolescents. DESIGN: Food choice was assessed using the validated New Zealand Adolescent FFQ. Principal components analysis was used to determine dietary patterns. Trained research assistants measured participants' height and body mass. Cardiorespiratory fitness was assessed in a subset of participants using the multistage 20 m shuttle run. The level and stage were recorded, and the corresponding VO2max was calculated. Differences in mean VO2max according to sex and BMI were assessed using t tests, while associations between cardiorespiratory fitness and dietary patterns were examined using linear regression analyses adjusted for age, sex, school attended, socio-economic deprivation and BMI. SETTING: Secondary schools in Otago, New Zealand. SUBJECTS: Students (n 279) aged 14-18 years who completed an online lifestyle survey during a class period. RESULTS: Principal components analysis produced three dietary patterns: 'Treat Foods', 'Fruits and Vegetables' and 'Basic Foods'. The 279 participants who provided questionnaire data and completed cardiorespiratory fitness testing had a mean age of 15·7 (sd 0·9) years. Mean VO2max was 45·8 (sd 6·9) ml/kg per min. The 'Fruits and Vegetables' pattern was positively associated with VO2max in the total sample (ß=0·04; 95%CI 0·02, 0·07), girls (ß=0·06; 95% CI 0·03, 0·10) and boys (ß=0·03; 95% CI 0·01, 0·05). CONCLUSIONS: These results indicate that increase in cardiorespiratory fitness was associated with a healthier dietary pattern, suggesting both should be targeted as part of a global lifestyle approach. Longitudinal studies are needed to confirm this association in relation to health outcomes in New Zealand adolescents.

Diet quality is associated with measures of body fat in adolescents from Otago, New Zealand.

OBJECTIVE: To examine the potential associations between diet quality and multiple measures of body composition in a sample of New Zealand adolescents aged 14-18 years. DESIGN: Cross-sectional survey of eleven high schools in Otago, New Zealand. Each participant completed an online FFQ and a New Zealand Diet Quality Index for Adolescents (NZDQI-A) score was calculated based on variety and adequacy of intake for five major food groups. Besides height and waist circumference measurements, body composition was assessed using segmental bio-impedance analysis. Generalized estimating equations were used to examine associations between diet quality and body composition in models adjusted for sex, age, ethnicity and socio-economic status. SETTING: High schools in Otago, New Zealand. SUBJECTS: High-school students (n 681, 56 % male, mean age 16·1 (sd 1·5) years) participating in the Otago School Students Lifestyle Survey Two. RESULTS: Higher NZDQI-A scores were significantly associated with lower body fat percentage (ß=-0·19; 95 % CI -0·35, -0·04; P=0·014), fat-to-lean mass ratio (ß=-0·26; 95 % CI -0·46, -0·05; P=0·016) and lower fat mass index (ß=-0·23; 95 % CI -0·45, -0·004; P=0·046) after multivariate adjustment. No association was found between NZDQI-A and BMI, waist circumference or waist-to-height ratio. CONCLUSIONS: Diet quality, as measured by NZDQI-A, was associated only with measures of body fat, not measures of overall body size. Measures specific to body fat should be used for more accurate ascertainment of body composition in examining the diet-body composition associations in this age group.

Is the food environment surrounding schools associated with the diet quality of adolescents in Otago, New Zealand?

Using a sample of adolescents from schools in Otago, New Zealand, associations between food outlets around schools and dietary quality were investigated. Food outlet environment data were derived using GIS data. Multivariate regression analysis results showed that outlet density, in an 800m buffer around schools, of cafes and restaurants, supermarkets and takeaways was associated with higher Diet Quality Index scores in boys, and distance to nearest outlet for convenience stores, cafes and restaurants and supermarkets with lower scores for girls. Effect sizes were small, suggesting that the food environment around schools plays a minor role in adolescent diet quality.

Fluid and electrolyte balance during two different preseason training sessions in elite rugby union players.

The purpose of this study was to compare fluid balance between a resistance and an aerobic training sessions, in elite rugby players. It is hypothesized that resistance exercise will result in a higher prevalence of overdrinking, whereas during the aerobic session, underdrinking will be more prevalent. As with previous fluid balance studies, this was an observational study. Twenty-six players completed the resistance training session, and 20 players completed the aerobic training session. All players were members of an elite rugby union squad competing in the southern hemisphere's premier competition. For both sessions, players provided a preexercise urine sample to determine hydration status, pre- and postexercise measures of body mass, and blood sodium concentration were taken, and the weight of drink bottles were recorded to calculate sweat rates and fluid intake rates. Sweat patches were positioned on the shoulder of the players, and these remained in place throughout each training session and were later analyzed for sodium concentration. The percentage of sweat loss replaced was higher in the resistance (196 ± 130%) than the aerobic training session (56 ± 17%; p = 0.002). Despite this, no cases of hyponatremia were detected. The results also indicated that more than 80% of players started training in a hypohydrated state. Fluid intake seems to differ depending on the nature of the exercise session. In this group of athletes, players did not match their fluid intakes with their sweat loss, resulting in overdrinking during resistance training and underdrinking in aerobic training. Therefore, hydration strategies and education need to be tailored to the exercise session. Furthermore, given the large number of players arriving at training hypohydrated, improved hydration strategies away from the training venue are required.

Probiotic supplementation reduces the duration and incidence of infections but not severity in elite rugby union players.

OBJECTIVES: The attenuation of the number and severity of infections is of importance to athletes. Probiotics use has increased over recent years with beneficial effects believed to include improvements in immune function. Research has focused on their effectiveness for reducing the number, duration and severity of infections amongst endurance athletes. At present no research has been undertaken with team sport athletes. This randomised controlled trial aimed to determine the effectiveness of probiotics on the number, duration and severity of infections amongst elite union rugby players. DESIGN: Randomised control trial with two arms; placebo and probiotic. METHODS: Thirty elite rugby union players were allocated in random order to receive a probiotics supplement or a placebo for four weeks each. Supplements were consumed on a daily basis. There was a four week washout period between treatments. Participants completed a daily diary to identify and rate the severity of any infectious symptoms. RESULTS: During the probiotic treatment 14/30 participants never experienced a single upper respiratory tract illness (URTI) or gastrointestinal (GI) episode, compared to 6/30 on the placebo supplementation (p=0.033). The mean±standard deviation for the number of days of illness tended to be higher for the placebo, (5.8±6.6 days) than probiotic (3.4±4.6 days), (p=0.054). There was no significant difference in the severity of the symptoms between the two treatment groups (p=0.110). CONCLUSIONS: These positive effects of probiotic supplements provide evidence for the beneficial effects of daily supplementation with these probiotic strains in highly trained rugby union players.

Sleep duration and adiposity in older adolescents from Otago, New Zealand: relationships differ between boys and girls and are independent of food choice.

BACKGROUND: While relationships between sleep and BMI have been extensively studied in younger children the effect of sleep duration on adiposity in adolescents, who are undergoing rapid growth periods, is less well known. There is also a lack of consistent evidence on the role of sleep on other measures of adolescent body composition which may be more reflective of health than BMI in this age group. Previous research investigating whether these relationships differ between sexes is also inconsistent. Therefore the objective of this study was to investigate relationships between sleep duration and multiple body composition measures in older adolescents and to investigate if these relationships differ between boys and girls. METHODS: A web-based cross-sectional survey and anthropometric measurement of 685 adolescents (mean age 15.8 years) from 11 schools in Otago, New Zealand. Height and weight were measured by trained researchers and fat mass and fat-free mass were estimated using bio-impedance. Generalised estimating equations were used to examine associations between sleep duration and the following body composition measures: BMI, waist circumference (WC), waist-to-height ratio (WHtR), fat mass index (FMI), and fat-free mass index (FFMI). Analyses were adjusted for ethnicity, deprivation, the number of screens in the bedroom and fruit and vegetable consumption. RESULTS: When data from all participants were analysed together, no significant relationships were seen between sleep duration and any body composition measure but significant sex interactions were seen. An hour increase in average nightly sleep duration in boys only was associated with decreases of 1.2% for WC, 0.9% for WHtR, 4.5% for FMI and 1.4% for FFMI in multivariate models. Similar results were seen for weekday and weekend night sleep duration. CONCLUSIONS: Sex specific factors may play a role in relationships between sleep and body composition in older adolescents. The results in boys were most pronounced for FMI, a measure of total adiposity, which suggests that insufficient sleep in adolescent boys may affect fat mass more than lean mass and that the use of measures such as BMI may result in an under-estimation of relationships.