Showing papers by "Ben Desbrow published in 2014"

Acute Exercise and Hormones Related to Appetite Regulation: A Meta-Analysis

Abstract: Understanding of the impact of an acute bout of exercise on hormones involved in appetite regulation may provide insight into some of the mechanisms that regulate energy balance. In resting conditions, acylated ghrelin is known to stimulate food intake, while hormones such as peptide YY (PYY), pancreatic polypeptide (PP) and glucagon-like peptide 1 (GLP-1) are known to suppress food intake. The objective of this review was to determine the magnitude of exercise effects on levels of gastrointestinal hormones related to appetite, using systematic review and meta-analysis. Additionally, factors such as the exercise intensity, duration and mode, in addition to participant characteristics, were examined to determine their influence on these hormones. Major databases (PubMed, Scopus, Google Scholar, Science Direct, Academic Search Premier and EBSCOHost) were searched, through February 2013, for original studies, abstracts, theses and dissertations that examined responses of appetite hormones to acute exercise. Studies were included if they evaluated appetite hormone responses during and in the hours after an acute bout of exercise and reported area under the concentration–time curve (AUC) values for more than three datapoints. Studies reporting mean or pre/post-values only were excluded. Initially, 75 studies were identified. After evaluation of study quality and validity, using the Physiotherapy Evidence Database scale, data from 20 studies (28 trials) involving 241 participants (77.6 % men) had their data extracted for inclusion in the meta-analyses. A random-effects meta-analysis was conducted for acylated ghrelin (n = 18 studies, 25 trials) and PYY (n = 8 studies, 14 trials), with sub-group analyses and meta-regressions being conducted for moderator variables. Because the number of studies was limited, fixed-effects meta-analyses were performed on PP data (n = 4 studies, 5 trials) and GLP-1 data (n = 5 studies, 8 trials). The results of the meta-analyses indicated that exercise had small to moderate effects on appetite hormone levels, suppressing acylated ghrelin (effect size [ES] Cohen’s d value −0.20, 95 % confidence interval [CI] −0.373 to −0.027; median decrease 16.5 %) and increasing PYY (ES 0.24, 95 % CI 0.007 to 0.475; median increase 8.9 %), GLP-1 (ES 0.275, 95 % CI −0.031 to 0.581; median increase 13 %), and PP (ES 0.50, 95 % CI 0.11 to 0.89; median increase 15 %). No significant heterogeneity was detected in any meta-analysis (using Cochrane’s Q and I 2); however, publication biases were detected for all analyses. No moderator variables were observed to moderate the variability among the studies assessing acylated ghrelin and PYY. The majority of the present literature is acute in nature; therefore, longer-term alterations in appetite hormone concentrations and their influence on food and beverage intake are unknown. Furthermore, our review was limited to English-language studies and studies reporting AUC data. An acute bout of exercise may influence appetite by suppressing levels of acylated ghrelin while simultaneously increasing levels of PYY, GLP-1 and PP, which may contribute to alterations in food and drink intake after acute exercise. Further longitudinal studies and exploration into mechanisms of action are required in order to determine the precise role these hormones play in long-term appetite responses to an exercise intervention.

Sports Dietitians Australia Position Statement: Sports Nutrition for the Adolescent Athlete

Abstract: It is the position of Sports Dietitians Australia (SDA) that adolescent athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the demands of growth and development. As such, SDA established an expert multidisciplinary panel to undertake an independent review of the relevant scientific evidence and consulted with its professional members to develop sports nutrition recommendations for active and competitive adolescent athletes. The position of SDA is that dietary education and recommendations for these adolescent athletes should reinforce eating for long term health. More specifically, the adolescent athlete should be encouraged to moderate eating patterns to reflect daily exercise demands and provide a regular spread of high quality carbohydrate and protein sources over the day, especially in the period immediately after training. SDA recommends that consideration also be given to the dietary calcium, Vitamin D and iron intake of adolescent athletes due to the elevated risk of deficiency of these nutrients. To maintain optimal hydration, adolescent athletes should have access to fluids that are clean, cool and supplied in sufficient quantities before, during and after participation in sport. Finally, it is the position of SDA that nutrient needs should be met by core foods rather than supplements, as the recommendation of dietary supplements to developing athletes over-emphasizes their ability to manipulate performance in comparison with other training and dietary strategies.

Single and combined effects of beetroot juice and caffeine supplementation on cycling time trial performance.

Abstract: Both caffeine and beetroot juice have ergogenic effects on endurance cycling performance. We investigated whether there is an additive effect of these supplements on the performance of a cycling ti...

Time-course dependent changes in the transcriptome of human skeletal muscle during recovery from endurance exercise: from inflammation to adaptive remodeling

Abstract: Reprogramming of gene expression is fundamental for skeletal muscle adaptations in response to endurance exercise. This study investigated the time course-dependent changes in the muscular transcriptome after an endurance exercise trial consisting of 1 h of intense cycling immediately followed by 1 h of intense running. Skeletal muscle samples were taken at baseline, 3 h, 48 h, and 96 h postexercise from eight healthy, endurance-trained men. RNA was extracted from muscle. Differential gene expression was evaluated using Illumina microarrays and validated with qPCR. Gene set enrichment analysis identified enriched molecular signatures chosen from the Molecular Signatures Database. Three hours postexercise, 102 gene sets were upregulated [family wise error rate (FWER), P < 0.05], including groups of genes related with leukocyte migration, immune and chaperone activation, and cyclic AMP responsive element binding protein (CREB) 1 signaling. Forty-eight hours postexercise, among 19 enriched gene sets (FWER, P < 0.05), two gene sets related to actin cytoskeleton remodeling were upregulated. Ninety-six hours postexercise, 83 gene sets were enriched (FWER, P < 0.05), 80 of which were upregulated, including gene groups related to chemokine signaling, cell stress management, and extracellular matrix remodeling. These data provide comprehensive insights into the molecular pathways involved in acute stress, recovery, and adaptive muscular responses to endurance exercise. The novel 96 h postexercise transcriptome indicates substantial transcriptional activity potentially associated with the prolonged presence of leukocytes in the muscles. This suggests that muscular recovery, from a transcriptional perspective, is incomplete 96 h after endurance exercise involving muscle damage.

An exploration of individuals' preferences for nutrition care from Australian primary care health professionals

Abstract: This qualitative study explored individuals' preferences regarding the provision of nutrition care from Australian health professionals and the factors influencing their preferences. Thirty-eight individuals aged 53±8 years, living with a lifestyle-related chronic disease or risk factor for lifestyle-related chronic disease, participated in a semi-structured telephone interview. Participants were asked questions regarding their perceptions of which Australian health professionals provide nutrition care, their preferences for this care and the factors influencing their preferences. Interviews were transcribed verbatim and analysed thematically using a constant-comparison approach. General practitioners were the most recognised health professional that provided nutrition care to patients, followed by dietitians. General practitioners were regarded by most participants as the preferred provider of nutrition care because they were perceived to provide trustworthy and personalised nutrition care. Participants reported confusion regarding the professional differences between dietitians and nutritionists, and appealed for more information to be available to individuals that are considering consulting an Australian health professional for nutrition care. The findings of this study suggest that general practitioners are the preferred providers of nutrition care for many individuals living with a lifestyle-related chronic disease. Considering the increasing presentation of patients with lifestyle-related chronic disease in general practice, it is anticipated that the demand on general practitioners to provide nutrition care to patients will increase in the future.

Time course-dependent changes in the transcriptome of human skeletal muscle during recovery from endurance exercise: From inflammation to adaptive remodeling

Abstract: Re-programming of gene expression is fundamental for skeletal muscle adaptations in response to endurance exercise. This study investigated the time-course dependent changes in the muscular transcriptome following an endurance exercise trial consisting of 1 h of intense cycling immediately followed by 1 h of intense running. Skeletal muscle samples were taken at baseline, 3 h, 48 h, and 96 h post-exercise from eight healthy, endurance-trained, male individuals. RNA was extracted from muscle. Differential gene expression was evaluated using Illumina microarrays and validated with qPCR. Gene set enrichment analysis identified enriched molecular signatures chosen from the Molecular Signatures Database. Three h post-exercise, 102 gene sets were up-regulated [family wise error rate (FWER), P < 0.05]; including groups of genes related with leukocyte migration, immune and chaperone activation, and cyclic AMP responsive element binding protein (CREB) 1-signaling. Forty-eight h post-exercise, among 19 enriched gene sets (FWER, P < 0.05), two gene sets related to actin cytoskeleton remodeling were up-regulated. Ninety-six h post-exercise, 83 gene sets were enriched (FWER, P < 0.05), 80 of which were up-regulated; including gene groups related to chemokine signaling, cell stress management, and extracellular matrix remodeling. These data provide comprehensive insights into the molecular pathways involved in acute stress, recovery, and adaptive muscular responses to endurance exercise. The novel 96 h post-exercise transcriptome indicates substantial transcriptional activity, potentially associated with the prolonged presence of leukocytes in the muscles. This suggests that muscular recovery, from a transcriptional perspective, is incomplete 96 h after endurance exercise involving muscle damage.

The effect of a caffeinated mouth-rinse on endurance cycling time-trial performance.

Abstract: The purpose of this study was to investigate if acute caffeine exposure via mouth-rinse improved endurance cycling time-trial performance in well-trained cyclists. It was hypothesized that caffeine exposure at the mouth would enhance endurance cycling time-trial performance. Ten well-trained male cyclists (mean ± SD: 32.9 ± 7.5 years, 74.7 ± 5.3 kg, 176.8 ± 5.1cm, VO₂peak = 59.8 ± 3.5 ml·kg⁻¹·min⁻¹) completed two experimental time-trials following 24 hr of dietary and exercise standardization. A randomized, double-blind, placebo-controlled, cross-over design was employed whereby cyclists completed a time-trial in the fastest time possible, which was equivalent work to cycling at 75% of peak aerobic power output for 60 min. Cyclists were administered 25 ml mouth-rinses for 10 s containing either placebo or 35 mg of anhydrous caffeine eight times throughout the time-trial. Perceptual and physiological variables were recorded throughout. No significant improvement in time-trial performance was observed with caffeine (3918 ± 243 s) compared with placebo mouth-rinse (3940 ± 227 s). No elevation in plasma caffeine was detected due to the mouth-rinse conditions. Caffeine mouth-rinse had no significant effect on rating of perceived exertion, heart rate, rate of oxygen consumption or blood lactate concentration. Eight exposures of a 35 mg dose of caffeine at the buccal cavity for 10s does not significantly enhance endurance cycling time-trial performance, nor does it elevate plasma caffeine concentration.

Comparing the rehydration potential of different milk based drinks to a carbohydrate-electrolyte beverage

Abstract: The aim of this study was to compare the rehydration potential of a carbohydrate–electrolyte beverage with several varieties of milk following exercise-induced fluid losses. Fifteen male participan...

Caffeine consumption around an exercise bout: effects on energy expenditure, energy intake, and exercise enjoyment

Abstract: Combining an exercise and nutritional intervention is arguably the optimal method of creating energy imbalance for weight loss. This study sought to determine whether combining exercise and caffein...

The self-perceived knowledge, skills and attitudes of Australian practice nurses in providing nutrition care to patients with chronic disease

Abstract: Background. Nutrition is important for the management of chronic diseases. While practice nurses have numerous roles in primary care, the expectations on practice nurses to provide nutrition care for chronic disease management are increasing. The self-perceived knowledge, skills and attitudes of practice nurses in providing nutrition care has not been widely investigated. Objectives. The aim of the present study was to investigate the perceptions of Australian practice nurses on the provision of nutrition care for chronic disease management, including specific nutrition-related activities. Methods. A cross-sectional online survey was completed by 181 Australian practice nurses in 2013. Descriptive analyses were conducted on each survey item. The survey sample was tested for representation of the Australian practice nurse workforce, and associations between respondents’ demographic characteristics and responses to survey items were explored. Results. Almost all practice nurses (89%) felt it was important to address diet whenever they cared for a patient. Over half of practice nurses (61%) were unsure if their practices were effective in increasing patients’ compliance with nutritional recommendations. Nearly all practice nurses (98%) perceived further education on nutrition would assist them in their role. Conclusion. Practice nurses perceive they have an important role and favourable attitudes towards providing nutrition care; however, further training and education to enhance their selfperceived effectiveness is warranted. Future research should clarify whether an increase in nutrition-focused training results in improved effectiveness of nutrition care provided by practice nurses in terms of patient health outcomes.

Evaluation of a curriculum initiative designed to enhance the research training of dietetics graduates

Abstract: Aim: To qualitatively evaluate a learning and teaching intervention for developing research and evaluation competencies, structured around the experience of having to conduct a significant research project. Methods: A qualitative study utilising semi-structured interviews among a sample of 25 recent graduates from Griffith University's Master of Nutrition and Dietetics Program. Interviews explored student motivations for doing the research major, the student's experience of the full-time semester long research project, and the actual and perceived outcomes of this experience. Interviews were audiotaped, transcribed verbatim, and thematically analysed via open coding and triangular analysis by three of the authors. Results: All of the graduates interviewed had conducted research projects across a range of practice settings. Motivations for electing to do the research major varied from disinterest in other options to an opportunity to 'taste-test' research, to develop research competencies and secure pathways to later research studies. The student learning experience was described as intense, stressful but rewarding and a steep learning curve. Graduates reported that they learned much more than research competencies during this process and many converted this research activity into a research output (journal article or conference abstract). Students reflected on the strong sense of achievement associated with research outputs and the competitive advantage it had provided on seeking graduate employment. Conclusions: It is possible to develop graduate dietitians' research and evaluation competencies using curriculum initiatives that exploit experiential learning. Exposing students to the research practice cycle culminating in peer-reviewed publication builds research self-efficacy and positions students for good employment outcomes.

Attendance, weight and waist circumference outcomes of patients with type 2 diabetes receiving Medicare-subsidised dietetic services

Abstract: The aim of the present study was to investigate the participation and weight and waist circumference outcomes of patients with type 2 diabetes (T2D) receiving Medicare-subsidised dietetic services. A prospective observational study was conducted between January and September 2011 involving three private practice dietitians who provided services at 11 medical centres in south-east Queensland. All patients with T2D who were referred by their general practitioner (GP) to one of the dietitians as part of their team care arrangements were asked to participate. Participants’ attendance at consultations was recorded for the study duration. The dietitian collected weight and waist circumference measures at each consultation. In all, 129 participants (mean age 58.9 ± 15.7 years; mean body mass index 32.2 ± 5.6 kg m–2) were included in the study. The most frequent number of consultations allocated to a dietitian was two. Small, but significant reductions in bodyweight (1.9 ± 2.9 kg; P ≤ 0.05) and waist circumference (2.0 ± 4.8 cm; P ≤ 0.05) were observed from the initial to final consultation. Participants who attended more than two consultations lost significantly more weight than those who attended two consultations only (3.7 ± 4.2 vs 1.1 ± 1.6 kg, respectively; P ≤ 0.05). Almost one-third of participants (n = 38; 29%) did not complete the allocated number of consultations available through their referral. Modest weight and waist circumference reductions are achievable for patients with T2D receiving Medicare-subsidised dietetic services. The clinical significance of these reductions requires further investigation. Patients who attend more consultations with a dietitian may experience further improvements in weight and waist circumference outcomes. However, many patients do not complete the number of consultations allocated. Further research is required to explore the determinants of attendance at consultations in order to maximise potential improvements in health outcomes for patients receiving Medicare-subsidised dietetic services.

Direct observation of the nutrition care practices of Australian general practitioners

Abstract: INTRODUCTION: Nutrition care refers to nutrition-related advice or counselling provided by health professionals in an attempt to improve the nutrition behaviour of patients. AIM: The aim of this study was to describe the practices of a sample of Australian general practitioners (GPs) when providing nutrition care to adult patients. METHODS: Eighteen GPs (13 male, 5 female) were observed by fourth-year medical students during their general practice rotation. Each GP was observed for five consultations that included nutrition care, totalling 90 observed consultations. In each consultation, students completed a 31-item nutrition care checklist of nutrition care practices that could feasibly occur in a standard consultation. Each practice was marked with either a ‘yes’ (completed), ‘no’ (did not complete) or ‘completed by practice nurse prior to or after the consultation’. RESULTS: Twenty-eight nutrition care practices were observed at least once. The most frequently observed practices were measuring and discussing blood pressure (76.7%; n=69), followed by general questions about current diet (74.4%; n=67). Approximately half of the consultations included a statement of a nutrition-related problem (52.2%; n=47), and the provision of nutrition advice that focused on a nutrient (45.6%; n=41) or food group (52.2%; n=47). Consultations with male GPs, as well as GPs with more than 25 years of experience, were associated with an increased number of nutrition care practices per consultation. DISCUSSION: The GPs performed nutrition care practices in varying frequencies. Further research is required to identify the most effective GP nutrition care practices to improve the nutrition behaviour of patients.

Patient perceptions of the role of nutrition for pressure ulcer prevention in hospital: an interpretive study.

Abstract: PURPOSE: The aims of this study were to explore (a) patients' perceptions of the role of nutrition in pressure ulcer prevention; and (b) patients' experiences with dieticians in the hospital setting. DESIGN: Interpretive qualitative study. SUBJECTS AND SETTING: The sample comprised 13 females and 7 males. Their mean age was 61.3 +/- 12.6 years (mean +/- SD), and their average hospital length of stay was 7.4 +/- 13.0 days. The research setting was a public health hospital in Australia. METHODS: In this interpretive study, adult medical patients at risk of pressure ulcers due to restricted mobility participated in a 20 to 30 minute interview using a semi-structured interview guide. Interview questions were grouped into 2 domains; perceptions on the role of nutrition for pressure ulcer prevention; and experiences with dieticians. Recorded interviews were transcribed and analyzed using content analysis. RESULTS: Within the first domain, 'patient knowledge of nutrition in pressure ulcer prevention,' there were varying patient understandings of the role of nutrition for prevention of pressure ulcers. This is reflected in 5 themes: (1) recognizing the role of diet in pressure ulcer prevention; (2) promoting skin health with good nutrition; (3) understanding the relationship between nutrition and health; (4) lacking insight into the role of nutrition in pressure ulcer prevention; and (5) acknowledging other risk factors for pressure ulcers. Within the second domain, patients described their experiences with and perceptions on dieticians. Two themes emerged, which expressed differing opinions around the role and reputation of dieticians; they were receptive of dietician input; and displaying ambivalence towards dieticians' advice. CONCLUSIONS: Hospital patients at risk for pressure ulcer development have variable knowledge of the preventive role of nutrition. Patients had differing perceptions of the importance and value of information provided by dieticians.

Comparing the Effects of Alcohol Mixed with Artificially-Sweetened and Carbohydrate Containing Beverages on Breath Alcohol Concentration

Abstract: This study investigated the impact of alcohol mixed with artificially sweetened or carbohydrate containing beverages on breath alcohol concentration s (BrAC) under various levels of hydration status. Two groups of males participated in 3 experimental trials where alcohol was consumed under three different levels of hydration status. One group received alcohol mixed with an artificially sweetened beverage and the other group received alcohol mixed with a CHO-containing mixer in each trial. Significantly higher peak BrACs were observed when alcohol was consumed with an artificially sweetened beverage compared to a CHO-containing beverage under all levels of hydration status. Subjective ratings of intoxication and impairment were not different between the two groups under any of the hydration conditions. Mixing alcohol with an artificially sweetened drink results in higher BrACs, but no detectable differences in feelings of intoxication. These findings may have legal consequences for individuals who consume alcohol without co-ingestion of CHO and intend to operate a motor vehicle. Language: en

Acute Exercise and Hormones Related Appetite Regulation: Comparison of Meta-analytical Methods

Abstract: We thank you for the opportunity to discuss our recent paper [1] and the concerns brought forward by Professor Atkinson and colleagues [2]. We also thank Professors Atkinson and Stensel and Ms. Douglas for bringing these issues to our attention. These comments highlight potential issues in meta-analyses of crossover trials that may often be overlooked [3]. We acknowledge that we did not initially account for the crossover nature of the studies in our analysis. Thus, as Atkinson and colleagues have suggested, our results may have yielded a more conservative outcome in comparison to other methods because we treated the data as independent samples. Given the volatile nature and the relatively small levels of these hormones in the circulation, we felt it necessary to exercise caution [4]. However, in deference to these concerns, we re-performed the analysis using acylated ghrelin (AG) as an example with paired comparisons via three methods. First, correlation coefficients were calculated as per Elbourne and colleagues [3] from the reported means and standard deviations. The second method was performed similarly, except that a paired t statistic was calculated for each study. If an exact p value was reported, the inverse of the t distribution (TINV) function in Microsoft Excel was used to calculate the t statistic from the p value and degrees of freedom. If no exact p value was reported, the t statistic was calculated as follows: (difference in means)/[(standard deviation of the difference)/(H(n)]. This t statistic was then applied to the formula (t)/[(t) ? (n 1)] to estimate R [5]. Finally, the square root of R was taken to yield the correlation coefficient r. These estimates were then compared with the standardised mean differences we had reported previously. The median correlation coefficients for the first two methods were 0.68 (range 0.11–0.94) and 0.60 (range 0.11–0.92), respectively. The third method used the estimated paired t statistic, means, and sample sizes to estimate the effect sizes (ESs) and standard error. Results of the meta-analyses for AG are shown in Table 1 below. As seen in Table 1, the methods using the estimated correlation coefficients yielded estimates very similar to our original model, albeit with a tighter confidence interval. More individual studies had ESs that significantly differed from zero (n = 8 for each). When using the estimated t statistic, the ES estimate and confidence interval became comparatively inflated. However, we admit that because we only had access to means and summary data, the derived r and t statistic values are only estimates. For the meta-regression analyses, the only metaregression significant in all three new models was exercise intensity. An inverse relationship was observed, such that as intensity increased, the ES was more negative (i.e. more potent exercise-induced suppression of AG). This supports the findings of recent studies that have directly compared the magnitude of the post-exercise AG response after M. M. Schubert (&) B. Desbrow School of Public Health, Research Centre for Health Practice Innovation, Griffith Health Institute, Griffith University, Southport, QLD, Australia e-mail: m.schubert@griffith.edu.au

immune response to physiological stress exercise reveals novel signaling mechanisms in the Transcriptome analysis of neutrophils after endurance

Abstract: You might find this additional info useful...This article cites 57 articles, 29 of which can be accessed free at:/content/114/12/1677.full.html#ref-list-1 This article has been cited by 1 other HighWire hosted articles€[Abstract] [Full Text] [PDF] J Appl Physiol, February 1, 2014; 116 (3): 274-287.and Andrew C. BulmerRoss Lazarus, Barbara Wessner, David Cameron-Smith, Karl-Heinz Wagner, Luke J. Haseler Oliver Neubauer, Surendran Sabapathy, Kevin J. Ashton, Ben Desbrow, Jonathan M. Peake,recovery from endurance exercise: from inflammation to adaptive remodelingTime course-dependent changes in the transcriptome of human skeletal muscle duringUpdated information and services including high resolution figures, can be found at:/content/114/12/1677.full.html Additional material and information about Journal of Applied Physiology can be found at:http://www.the-aps.org/publications/japplThis information is current as of June 26, 2014.€

Supplement use in masters athletes

Abstract: Age-related changes influence all physiological systems, including those used during exercise and sport. Highlighting masters athletes—older adults who train and compete in organized sports—Nutrition and Performance in Masters Athletes examines the extent to which regular physical training can impact these changes. This book bridges the gap between theory and practice, addressing nutritional, exercise and sport sciences, and the actual performance of masters athletes and older exercisers. It reviews in detail many age-related changes that occur in the physiological systems, provides implications of these changes for masters athletes, coaches and clinicians, explores scientifically-based methods to maximize sprint, strength and power, team sport players, endurance and ultra-endurance performance, and focuses on the unique nutritional needs of master athletes. [Book Synopsis]