Showing papers by "Ben Desbrow published in 2017"

Caffeine, coffee, and appetite control: a review.

Abstract: Coffee and caffeine consumption has global popularity. However, evidence for the potential of these dietary constituents to influence energy intake, gut physiology, and appetite perceptions remains unclear. The purpose of this review was to examine the evidence regarding coffee and caffeine's influence on energy intake and appetite control. The literature was examined for studies that assessed the effects of caffeine and coffee on energy intake, gastric emptying, appetite-related hormones, and perceptual measures of appetite. The literature review indicated that coffee administered 3-4.5 h before a meal had minimal influence on food and macronutrient intake, while caffeine ingested 0.5-4 h before a meal may suppress acute energy intake. Evidence regarding the influence of caffeine and coffee on gastric emptying, appetite hormones, and appetite perceptions was equivocal. The influence of covariates such as genetics of caffeine metabolism and bitter taste phenotype remain unknown; longer controlled studies are needed.

The Effect of Fluid Intake Following Dehydration on Subsequent Athletic and Cognitive Performance: a Systematic Review and Meta-analysis.

Abstract: The deleterious effects of dehydration on athletic and cognitive performance have been well documented. As such, dehydrated individuals are advised to consume fluid in volumes equivalent to 1.25 to 1.5 L kg−1 body mass (BM) lost to restore body water content. However, individuals undertaking subsequent activity may have limited time to consume fluid. Within this context, the impact of fluid intake practices is unclear. This systematic review investigated the effect of fluid consumption following a period of dehydration on subsequent athletic and cognitive performance. PubMed (MEDLINE), Web of Science (via Thomas Reuters) and Scopus databases were searched for articles reporting on athletic (categorized as: continuous, intermittent, resistance, sport-specific and balance exercise) or cognitive performance following dehydration of participants under control (no fluid) and intervention (fluid intake) conditions. Meta-analytic procedures determined intervention efficacy for continuous exercise performance. Sixty-four trials (n = 643 participants) derived from 42 publications were reviewed. Dehydration decreased BM by 1.3–4.2%, and fluid intake was equivalent to 0.4–1.55 L kg−1 BM lost. Fluid intake significantly improved continuous exercise performance (22 trials), Hedges’ g = 0.46, 95% CI 0.32, 0.61. Improvement was greatest when exercise was performed in hotter environments and over longer durations. The volume or timing of fluid consumption did not influence the magnitude of this effect. Evidence indicating a benefit of fluid intake on intermittent (10 trials), resistance (9 trials), sport-specific (6 trials) and balance (2 trials) exercise and on cognitive performance (15 trials) was less apparent and requires further elucidation. Fluid consumption following dehydration may improve continuous exercise performance under heat stress conditions, even when the body water deficit is modest and fluid intake is inadequate for complete rehydration.

Personal Trainer Perceptions of Providing Nutrition Care to Clients: A Qualitative Exploration

Abstract: Personal trainers are well placed to provide basic nutrition care in line with national dietary guidelines. However, many personal trainers provide nutrition care beyond their scope of practice and this has been identified as a major industry risk due to a perceived lack of competence in nutrition. This paper explores the context in which personal trainers provide nutrition care, by understanding personal trainers' perceptions of nutrition care in relation to their role and scope of practice. Semistructured telephone interviews were conducted with 15 personal trainers working within Australia. Thematic analysis was used to identify key themes. All personal trainers reported to provide nutrition care and reported that nutrition care was an important component of their role. Despite this, many were unaware or uncertain of the scope of practice for personal trainers. Some personal trainers reported a gap between the nutrition knowledge they received in their formal education, and the knowledge they needed to optimally support their clients to adopt healthy dietary behaviors. Overall, the personal training context is likely to be conducive to providing nutrition care. Despite concerns about competence personal trainers have not modified their nutrition care practices. To ensure personal trainers provide nutrition care in a safe and effective manner, greater enforcement of the scope of practice is required as well as clear nutrition competencies or standards to be developed during training.

Modulation of chemotherapy-induced cytotoxicity in SH-SY5Y neuroblastoma cells by caffeine and chlorogenic acid.

Abstract: Chemotherapy is an important treatment modality for malignancy but is limited by significant toxicity and it susceptibility to numerous drug interactions. While the interacting effects with medications are well known, there is limited evidence on the interaction with commonly consumed food and natural products. The aim of this study was to evaluate the bioactive constituents of coffee (caffeine and chlorogenic acid) on the cytotoxicity of doxorubicin, gemcitabine, and paclitaxel in vitro. Pretreatment with caffeine (100 nM and 10 μM) sensitized SH-SY5Y cells to doxorubicin-induced toxicity and increased apoptosis and sensitized PC3 cells to gemcitabine-induced toxicity. Pretreatment with 10 μM caffeine decreased total cell reactive oxygen species (ROS) production but increased mitochondrial ROS production. In contrast, caffeine (10 nM and 10 μM) protected cells against gemcitabine-induced toxicity and apoptosis. Similarly, 1 μM and 10 μM caffeine protected cells against paclitaxel-induced toxicity and mitochondrial ROS production. Chlorogenic acid had no effect on chemotherapy-induced toxicity in SH-SY5Y cells. In conclusion, this study provides preliminary evidence that caffeine, not chlorogenic acid, modulates the cytotoxicity of doxorubicin, gemcitabine, and paclitaxel in SH-SY5Y cells via different mechanisms.

Test-Retest Reliability of Simulated Driving Performance: A Pilot Study

Abstract: Twenty-seven volunteers completed three simulated driving tests to determine test-retest reliability of performance on a low-cost, fixed-base computerized driving simulator. One retest was completed a few hours after the initial drive, and the final retest was completed 7 days following the initial test drive. Driving performance was compared using measures of vehicle control, speed, and reaction time to critical events. A measure of participants’ ability to inhibit a pre-potent response was also assessed using an inhibition task during each drive, with the number of incorrect inhibition responses recorded. Practice effects were evident for measures of vehicle control (deviation of lane position and number of line crossings) and participants’ ability to withhold responses to inhibition tasks. Good test-retest reliability was observed for measures of vehicle control, speed, reaction time, and variability measures. Poor test-retest reliability was observed for the number of stopping failures observed during driving. The findings from this study suggest that the driving scenario used provides reliable assessment tasks that could be used to track the effects of pharmacological treatments on driving performance. However, an additional familiarization drive should be included as part of future study protocols employing this driving scenario to reduce learning effects during trials. Care should also be taken when interpreting results from tasks with low test-retest reliability.

Inaccuracies in caffeine intake quantification and other important limitations in recent publication by Gonçalves et al.

Abstract: to the editor: It was with great interest that we read the recent article by Goncalves et al. ([2][1]). Given the Journal of Applied Physiology ’s reputation for quality and the forthright title, we anticipated a significant advance in our understanding. Indeed, the study displays high standards

An International Comparison of Nutrition Education Standards, Occupational Standards and Scopes of Practice for Personal Trainers

Abstract: Personal trainers are well placed to provide nutrition care in line with their recommended scope of practice. However, providing nutrition care beyond their recommended scope of practice has been identified as an industry risk. The International Confederation of Registers for Exercise Professionals (ICREPs) have international standards for nutrition knowledge and skills that are recommended for all fitness professionals, including personal trainers. This study investigates whether the ICREPs standards align with i) national nutrition education standards and ii) national nutrition occupational standards and scopes of practice for personal trainers within ICREPs affiliated countries. Content analysis of each standard and/or scope of practice was undertaken to extract nutrition statements. Extracted statements were matched with nutrition components of the ICREPs standards to result in a score based on the number of aligned ICREPs knowledge and skills criteria. Ten countries, with 16 organizations, were identified as being involved in the development of national education standards, occupational standards, or scopes of practice for personal trainers. The educational and occupational standards varied widely among countries and had minimal alignment with the ICREPs standards. As such, the expected role of personal trainers in providing nutrition care appeared to differ between countries. Further work is required to support personal trainers to develop a level of knowledge and skills that enables the provision of safe, consistent, and effective nutrition care.

A Nutrition Recovery Station Following Recreational Exercise Improves Fruit Consumption but Does Not Influence Fluid Recovery

Abstract: Immediate postexercise access to fruit/fluid via a recovery "station" is a common feature of mass participation sporting events. Yet little evidence exists examining their impact on subsequent dietary intake. The aim of this study was to determine if access to fruit/water/sports drinks within a recovery station significantly alters dietary and fluid intakes in the immediate postexercise period and influences hydration status the next morning. 127 (79 males) healthy participants (M ± SD, age = 22.5 ± 3.5y, body mass (BM) = 73 ± 13kg) completed two self-paced morning 10km runs separated by 1 week. Immediately following the first run, participants were randomly assigned to enter (or not) the recovery station for 30min. All participants completed the alternate recovery option the following week. Participants recorded BM before and after exercise and measured Urine Specific Gravity (USG) before running and again the following morning. For both trial days, participants also completed 24h food and fluid records via a food diary that included photographs. Paired-sample t tests were used to assess differences in hydration and dietary outcome variables (Recovery vs. No Recovery). No difference in preexercise USG or BM change from exercise were observed between treatments (p's > .05). Attending the recovery zone resulted in a greater total daily fluid (Recovery = 3.37 ± 1.46L, No Recovery = 3.16 ± 1.32L, p = .009) and fruit intake (Recovery = 2.37 ± 1.76 servings, No Recovery = 1.55 ± 1.61 servings, p > .001), but had no influence on daily total energy (Recovery = 10.15 ± 4.2MJ, No Recovery = 10.15 ± 3.9MJ), or macronutrient intakes (p > .05). Next morning USG values were not different between treatments (Recovery = 1.018 ± 0.007, No Recovery = 1.019 ± 0.009, p > .05). Recovery stations provide an opportunity to modify dietary intake which promote positive lifestyle behaviors in recreational athletes.

The Influence of Mixers Containing Artificial Sweetener or Different Doses of Carbohydrate on Breath Alcohol Responses in Females

Abstract: Background: Breath alcohol responses may be affected by the presence of carbohydrate (CHO) in a beverage. This study investigated the impact of consuming alcohol with mixers containing various doses of CHO or an artificial sweetener on breath alcohol concentration (BrAC), ratings of intoxication and impairment, and cognitive performance in females. Methods: Twenty-six females (age 25.1 ± 0.7 years, mean ± standard deviation) completed a crossover study involving 4 trials. A dose of alcohol was consumed in each trial mixed with water (W), artificial sweetener (150 ± 1 mg aspartame [AS]), or CHO (15 g sucrose [15CHO] and 50 g sucrose [50CHO]). BrAC was sampled for 210 minutes following beverage ingestion and analyzed for peak BrAC and other parameters using WinNonlin noncompartmental pharmacokinetic modeling (cmax, tmax, area under the curve to the last measured time point [AUClast]). An objective measure of cognitive performance was assessed using a 4-choice reaction time (CRT) task. Estimation of BrAC, self-reported ratings of intoxication, and willingness to drive were recorded. Results: Mean peak BrAC was reduced in a dose–response manner when alcohol was consumed with CHO compared to both W and AS treatments (W: 0.054 ± 0.015%, AS: 0.052 ± 0.011%, 15CHO: 0.049 ± 0.008%, 50CHO: 0.038 ± 0.007%). No difference in peak BrAC was observed between W and AS treatments. WinNonlin parameters revealed significant differences in cmax and AUClast (W: 4.80 ± 1.12 g/dl/h, AS: 4.61 ± 0.92 g/dl/h, 15CHO: 4.10 ± 0.86 g/dl/h, 50CHO: 3.11 ± 0.58 g/dL/h) when CHO-containing beverages were consumed compared to W and AS treatments. No difference in tmax or CRT was observed between treatments. Participants were able to detect subtle differences in peak BrAC and reported greater ability to drive after consuming 50CHO compared to W. However, participant's willingness to drive and CRT did not differ between treatments. Conclusions: Consuming alcohol with CHO-containing mixers attenuates peak BrAC and reduces total alcohol exposure in a dose–response manner compared to drinks containing artificial sweetener or no additives. The effect of adding CHO to alcoholic beverages may translate to reduced risk of alcohol-related harms.