Publications by authors named "Christopher Irwin"

78 Publications

The Relationship Between Diet and Sleep in Older Adults: a Narrative Review.

Curr Nutr Rep 2021 Jun 14. Epub 2021 Jun 14.

Physical Activity Research Group, Central Queensland University, 160 Ann St, Brisbane, QLD, 4000, Australia.

Purpose Of Review: Older adults more frequently experience reduced sleep quality and quantity compared to younger adults. Diet is one modifiable lifestyle factor that may influence sleep outcomes in older adults. The purpose of this review is to synthesise the current literature investigating the impact of diet, including foods and nutrients, on the sleep quality and quantity of older adults.

Recent Findings: Overall, the observational and intervention studies suggest that following a Mediterranean diet, and the consumption of certain food items (e.g. milk), and nutrients (e.g. vitamin D and vitamin E) may influence (improve or reduce) sleep quality and quantity. This review describes the potential efficacy for dietary factors to improve sleep outcomes in older adults. However, given the heterogeneity of included studies in this review (i.e. aims, methodologies, and outcomes assessed), it is difficult to consolidate the available evidence to make specific recommendations. More targeted research exploring the relationship between diet and sleep in older adults is needed to strengthen the current evidence base.
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http://dx.doi.org/10.1007/s13668-021-00362-4DOI Listing
June 2021

Associations between health behaviors and mental health in Australian nursing students.

Nurse Educ Pract 2021 May 16;53:103084. Epub 2021 May 16.

Physical Activity Research Group, Appleton Institute, School of Health Medical and Applied Sciences, CQUniversity, Rockhampton, Australia. Electronic address:

Aim: Nursing students experience high levels of stress, anxiety and depression. This study examined associations between health behaviors and stress, anxiety and depression in Australian nursing students.

Design: this was a cross-sectional study.

Methods: Participants completed an online survey providing demographic information and responses to the 21-item Depression Anxiety Stress Scale, Fagerström Test for Nicotine Dependence, short Food Frequency Questionnaire, Alcohol Use Disorders Identification Test, International Physical Activity Questionnaire and Workforce Sitting Questionnaire. Associations were evaluated using multivariate linear regression.

Results: Mild to extremely severe stress (46.6%), anxiety (52.8%) and depression (42.2%) were prevalent. Intake of snack-foods was associated with higher depression (β = 8.66, p < 0.05) and stress (β = 3.92, p = 0.055) scores. More time spent sitting was associated with higher depression (β = 0.48, p < 0.001) and stress (β = 0.28, p < 0.05) scores. Skipping meals correlated with higher stress, anxiety and depression scores.

Conclusion: More support must be provided to nursing students to manage psychological distress and mental health during university study.
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http://dx.doi.org/10.1016/j.nepr.2021.103084DOI Listing
May 2021

The influence of exercise training volume alterations on the gut microbiome in highly-trained middle-distance runners.

Eur J Sport Sci 2021 Jun 13:1-9. Epub 2021 Jun 13.

Menzies Health Institute Queensland, Griffith University, Queensland, Australia.

The aim of this study was to determine the influence of training volume alterations on diversity and composition of the gut microbiome in a free-living cohort of middle-distance runners. Fourteen highly-trained middle-distance runners ( = 8 men; [Formula: see text]O = 70.1 ± 4.3 ml·kg·min;  = 6 women, [Formula: see text]O: 59.0 ± 3.2 ml·kg·min) completed three weeks of normal training (NormTr), three weeks of high-volume training (HVolTr; a 10, 20 and 30% increase in training volume during each successive week from NormTr), and a one-week taper (TaperTr; 55% exponential reduction in training volume from HVolTr week three). Faecal samples were collected before and immediately after each training phase to quantify alpha-diversity and composition of the gut microbiome. A three-day diet record was collected during each training phase and a maximal incremental running test was completed after each training phase. Results showed no significant changes in nutritional intake, alpha-diversity, or global microbial composition following HVolTr or TaperTr compared to NormTr ('s > 0.05). Following HVolTr, there was a significant decrease in Pasterellaceae ( = 0.03), ( = 0.02) ( = 0.03) ( = 0.02) and ( = 0.03), while ( = 0.03) significantly increased. These changes did not return to NormTr levels following TaperTr. This study shows that the alpha-diversity and global composition of the gut microbiome were unaffected by changes in training volume. However, an increase in training volume led to several changes at the lower taxonomy levels that did not return to pre-HVolTr levels following a taper period.
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http://dx.doi.org/10.1080/17461391.2021.1933199DOI Listing
June 2021

The Impact of Post-Prandial Delay Periods on Consumption of a Laboratory Breakfast Meal.

Appl Physiol Nutr Metab 2021 May 13. Epub 2021 May 13.

Griffith University, School of Allied Health Sciences and Griffith Health Institute, Gold Coast, Queensland, Australia, Gold Coast, Queensland, Australia, 4222.

This study examined the impact of varying the holding time following an ad libitum laboratory breakfast on acute dietary behaviour and subsequent intake. 24 participants (20 females (age: 23.4±6.3 y; BMI: 23.9±3.9 kg·m-2, mean±SD)) completed three trials following a quasi-randomized, crossover design. Each trial (seven day separation) incorporated a defined post-prandial delay (DPD) period of either zero (no delay), one or three hours following a buffet breakfast consumed over 30-minutes. Dietary intake outcomes included energy, macronutrient and core food group intakes. On completion of the DPD period, participants left the laboratory and recorded all food/beverages consumed for the remainder of the day. One-way repeated-measures ANOVA assessed all outcomes, with post hoc analysis conducted on significant main effects. Energy and carbohydrate intakes were significantly lower on no delay vs one hour (p = 0.014) and three hour (p = 0.06) DPD trials (EI: 1853±814 kJ vs. 2250±1345 kJ vs. 1948±1289 kJ; CHO: 68±34 g vs. 77±44 vs. 69±43 g; respectively). DPD periods did not influence the time to consume next meal or energy, macronutrient and core food group intakes for the remainder of the day. Delaying participants from leaving a laboratory alters dietary intake at an ad libitum test meal. The post-meal holding period is an important methodological consideration when planning laboratory studies to assess appetite. Novelty Bullets: 1. Delaying participants from leaving a laboratory alters dietary intake at ad libitum breakfast meals. 2. The length of the delay period did not affect dietary intake at ad libitum breakfast meals.
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http://dx.doi.org/10.1139/apnm-2020-0801DOI Listing
May 2021

Belief in caffeine's ergogenic effect on cognitive function and endurance performance: A sham dose-response study.

Hum Psychopharmacol 2021 May 3:e2792. Epub 2021 May 3.

School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia.

This study aimed to determine if belief in caffeine's ergogenic potential influences choice reaction time (CRT) and/or running performance. Twenty-nine healthy individuals (23.7 ± 5 years, 16 males) completed two trials (one week apart). Before the trials, participants indicated their "belief" in caffeine's ergogenic effects and previous "experience" using caffeine for performance. On arrival, participants randomly received either sham "Low (100mg; LD)" or "High (300mg; HD)" dose caffeine capsules 30-min before commencing the CRT test, followed by a 10km run. Paired samples t-tests determined differences between trials for CRT latency (Ex-Gaussian analysis; μ-, σ- and τ-) and running performance using the entire cohort and sub-groups exhibiting strong "beliefs"+/-"experience". Sham caffeine dose did not influence CRT (μ-, σ- and τ-respectively, LD: 400 ± 53ms vs. HD: 388 ± 41ms; LD: 35 ± 18ms vs. HD: 34 ± 17ms; LD: 50 ± 24ms vs. HD: 52 ± 19ms, all p's > 0.05). Neither belief (n = 6), nor belief + experience (n = 4), influenced this effect. Furthermore, caffeine dose did not influence run time (LD: 49.05 ± 3.75min vs. HD: 49.06 ± 3.85min, p = 0.979). Belief (n = 9) (LD: 48.93 ± 3.71min vs. HD: 48.9 ± 3.52min, p = 0.976), and belief + experience (n = 6) (LD: 48.68 ± 1.87min vs. HD: 49.55 ± 1.75min, p = 0.386) didn't influence this effect. A dose-response to sham caffeine ingestion was not evident on cognitive or endurance performance in healthy individuals, regardless of their convictions about caffeine's ergogenicity.
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http://dx.doi.org/10.1002/hup.2792DOI Listing
May 2021

Associations between health-related quality of life and health behaviors in Australian nursing students.

Nurs Health Sci 2021 Jun 15;23(2):477-489. Epub 2021 Apr 15.

Physical Activity Research Group, Appleton Institute, School of Health Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia.

Health-related quality of life (HRQoL) is being increasingly studied as an indicator of wellbeing. This study evaluated the HRQoL of nursing students and relationships between lifestyle behaviors including smoking, diet, alcohol intake and physical activity. A cross-sectional study was conducted in 2018 using the Short-Form 12V2 to measure the HRQoL of 475 students from both regional and metropolitan universities in Queensland, Australia. z-scores were aggregated into a Physical Composite Score (PCS) and a Mental Composite Score (MCS). Multivariate linear regression was used to explore the associations. Nursing students (94.5% female) had lower HRQoL scores relative to the general Australian population. Students enrolled at the regional university, with higher income; higher intakes of vitamin A, calcium, and iodine; and more physical activity had a higher Mental Composite Score, but those with health conditions and high intakes of meat, fat, carbohydrates, and sugar reported lower Physical Composite Score compared to their counterparts. Skipping breakfast, physical inactivity, and alcohol score were inversely associated with HRQoL. This study highlights the need for strategies to address the poor lifestyle and HRQoL in nursing students to support their physical and mental health.
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http://dx.doi.org/10.1111/nhs.12832DOI Listing
June 2021

Analysis of dietary intake, diet cost and food group expenditure from a 24-hour food record collected in a sample of Australian university students.

Nutr Diet 2021 04 2;78(2):174-182. Epub 2021 Feb 2.

School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia.

Aim: University students often cite increased monetary cost as a major barrier to improved eating behaviours. Here, we examine food expenditure behaviours in a sample of Australian university students.

Methods: Students (n = 147) collected and analysed a 24-hour food record to determine their food group and nutrient intakes, then costed the food and non-tap water beverages consumed in the amounts recorded. Diet cost and food group expenditure (absolute and relative to total diet cost) were calculated and compared across socio-demographic characteristics. Spearman's Rho correlations and partial correlations (controlling for energy intake) were also used to identify associations between diet cost and intake.

Results: The median (IQR) 24-hour diet cost was $12.42 ($7.06). However, students who worked ≥20 h·wk had a higher diet cost than those who worked <20 h·wk (P = .002) or were unemployed (P = .002). Relative food group expenditure also differed by sex, employment status and whether special dietary requirements were reported (P's < .05). For instance, males reported spending a smaller relative amount on the fruit and vegetables food groups and a larger relative amount on discretionary choices than females (P's < 0.05). Higher diet costs were also associated with greater intakes of the fruit, vegetables and lean meat and alternatives food groups, protein, alcohol, water and calcium, and lower intakes of the grain foods food group and carbohydrate (P's < .05).

Conclusions: These findings provide insight into university students' food expenditure behaviours and may assist health professionals to develop targeted strategies and tailored advice aimed at improving their dietary behaviours.
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http://dx.doi.org/10.1111/1747-0080.12662DOI Listing
April 2021

The Effect of Consuming Carbohydrate With and Without Protein on the Rate of Muscle Glycogen Re-synthesis During Short-Term Post-exercise Recovery: a Systematic Review and Meta-analysis.

Sports Med Open 2021 Jan 28;7(1). Epub 2021 Jan 28.

School of Allied Health Sciences, Griffith University, Southport, 4222, Queensland, Australia.

Background: Rapid restoration of muscle glycogen stores is imperative for athletes undertaking consecutive strenuous exercise sessions with limited recovery time (e.g. ≤ 8 h). Strategies to optimise muscle glycogen re-synthesis in this situation are essential. This two-part systematic review and meta-analysis investigated the effect of consuming carbohydrate (CHO) with and without protein (PRO) on the rate of muscle glycogen re-synthesis during short-term post-exercise recovery (≤ 8 h).

Methods: Studies were identified via the online databases Web of Science and Scopus. Investigations that measured muscle glycogen via needle biopsy during recovery (with the first measurement taken ≤ 30 min post-exercise and at least one additional measure taken ≤ 8 h post-exercise) following a standardised exercise bout (any type) under the following control vs. intervention conditions were included in the meta-analysis: part 1, water (or non-nutrient beverage) vs. CHO, and part 2, CHO vs. CHO+PRO. Publications were examined for methodological quality using the Rosendal scale. Random-effects meta-analyses and meta-regression analyses were conducted to evaluate intervention efficacy.

Results: Overall, 29 trials (n = 246 participants) derived from 21 publications were included in this review. The quality assessment yielded a Rosendal score of 61 ± 8% (mean ± standard deviation). Part 1: 10 trials (n = 86) were reviewed. Ingesting CHO during recovery (1.02 ± 0.4 g·kg body mass (BM) h) improved the rate of muscle glycogen re-synthesis compared with water; change in muscle glycogen (MG) re-synthesis rate = 23.5 mmol·kg dm h, 95% CI 19.0-27.9, p < 0.001; I = 66.8%. A significant positive correlation (R = 0.44, p = 0.027) was observed between interval of CHO administration (≤ hourly vs. > hourly) and the mean difference in rate of re-synthesis between treatments. Part 2: 19 trials (n = 160) were reviewed. Ingesting CHO+PRO (CHO: 0.86 ± 0.2 g·kg BM h; PRO: 0.27 ± 0.1 g·kg BM h) did not improve the rate of muscle glycogen re-synthesis compared to CHO alone (0.95 ± 0.3 g·kg BM h); MG re-synthesis rate = 0.4 mmol·kg  dm h, 95% CI -2.7 to 3.4, p = 0.805; I = 56.4%.

Conclusions: Athletes with limited time for recovery between consecutive exercise sessions should prioritise regular intake of CHO, while co-ingesting PRO with CHO appears unlikely to enhance (or impede) the rate of muscle glycogen re-synthesis.

Trial Registration: Registered at the International Prospective Register of Systematic Reviews (PROSPERO) (identification code CRD42020156841 ).
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http://dx.doi.org/10.1186/s40798-020-00297-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7843684PMC
January 2021

Determining the magnitude and duration of acute Δ-tetrahydrocannabinol (Δ-THC)-induced driving and cognitive impairment: A systematic and meta-analytic review.

Neurosci Biobehav Rev 2021 07 23;126:175-193. Epub 2021 Jan 23.

The University of Sydney, Lambert Initiative for Cannabinoid Therapeutics, Sydney, New South Wales, Australia; The University of Sydney, Brain and Mind Centre, Sydney, New South Wales, Australia; The University of Sydney, Faculty of Science, School of Psychology, Sydney, New South Wales, Australia.

The increasing legal availability of cannabis has important implications for road safety. This systematic review characterised the acute effects of Δ-THC on driving performance and driving-related cognitive skills, with a particular focus on the duration of Δ-THC-induced impairment. Eighty publications and 1534 outcomes were reviewed. Several measures of driving performance and driving-related cognitive skills (e.g. lateral control, tracking, divided attention) demonstrated impairment in meta-analyses of "peak" Δ-THC effects (p's<0.05). Multiple meta-regression analyses further found that regular cannabis users experianced less impairment than 'other' (mostly occasional) cannabis users (p = 0.003) and that the magnitude of oral (n = 243 effect estimates [EE]) and inhaled (n = 481 EEs) Δ-THC-induced impairment depended on various factors (dose, post-treatment time interval, the performance domain (skill) assessed) in other cannabis users (p's<0.05). The latter model predicted that most driving-related cognitive skills would 'recover' (Hedges' g=-0.25) within ∼5-hs (and almost all within ∼7-hs) of inhaling 20 mg of Δ-THC; oral Δ-THC-induced impairment may take longer to subside. These results suggest individuals should wait at least 5 -hs following inhaled cannabis use before performing safety-sensitive tasks.
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http://dx.doi.org/10.1016/j.neubiorev.2021.01.003DOI Listing
July 2021

Consistency of hangover experiences after a night of drinking: A controlled laboratory study.

Hum Psychopharmacol 2021 May 1;36(3):e2771. Epub 2020 Dec 1.

School of Allied Health Sciences, Griffith University, Gold Coast, Australia.

Objective: Research into cognitive performance during a hangover has produced equivocal findings. This study investigated the reliability of inducing hangover symptoms and effects on cognitive performance (including applied tasks) under standardised conditions.

Method: Twenty-one participants (13 M; 24 ± 3 years) completed two identical trials, involving alcohol consumption and an overnight laboratory stay. Outcome measures included: hangover severity (a single-item 'Hangover' rating, and a sum of hangover symptoms [Overall Symptoms Score (OSS)]), cognitive function (trail making test), simulated driving (standard deviation of lateral position; lane crossings), and typing performance. Spearman's correlations were used to assess reliability between trials for all participants, and when ratings of 'Hangover' were consistent.

Results: Participants demonstrated reliable 'Hangover' rating change from baseline (Trial A: 2.0 [2.0]; Trial B: 2.0 [2.0], rho = 0.680, p = 0.001), but not for OSS (Trial A: 8.0 [12.0]; Trial B: 5.0 [9.0], rho = 0.309, p = 0.173). Performance in cognitive/applied tasks (range rho = 0.447-0771) was consistent, except simulated driving (range rho = 0.035-0.272), however the impairment was trivial. The subgroup analysis did not reveal substantial changes in reliability.

Conclusion: A single 'Hangover' rating was a reliable way of determining 'mild' to 'moderate' hangover severity. The present data could be used to assist the methodological design of future hangover research.
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http://dx.doi.org/10.1002/hup.2771DOI Listing
May 2021

Natural Antimicrobials in the Dental Pulp.

J Endod 2020 Sep;46(9S):S2-S9

Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, Northern Ireland.

Introduction: Like many tissues, the dental pulp is equipped with innate and adaptive immune responses, designed to defend against infection and limit its spread. The pulp's innate immune response includes the synthesis and release of antimicrobial peptides by several dental pulp cell types. These naturally-occurring antimicrobial peptides have broad spectrum activity against bacteria, fungi and viruses. There is a resurgence of interest in the bioactivities of naturally-occurring antimicrobial peptides, largely driven by the need to develop alternatives to antibiotics.

Methods: This narrative review focused on the general properties of antimicrobial peptides, providing an overview of their sources and actions within the dental pulp.

Results: We summarized the relevance of antimicrobial peptides in defending the dental pulp, highlighting the potential for many of these antimicrobials to be modified or mimicked for prospective therapeutic use.

Conclusion: Antimicrobial peptides and novel peptide-based therapeutics are particularly attractive as emerging treatments for polymicrobial infections, such as endodontic infections, because of their broad activity against a range of pathogens.
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http://dx.doi.org/10.1016/j.joen.2020.06.021DOI Listing
September 2020

Cognitive effects of acute aerobic exercise: Exploring the influence of exercise duration, exhaustion, task complexity and expectancies in endurance-trained individuals.

J Sports Sci 2021 Jan 21;39(2):183-191. Epub 2020 Aug 21.

School of Allied Health Sciences, Griffith University , Gold Coast, Australia.

The cognitive effects of acute aerobic exercise were investigated in endurance-trained individuals. On two occasions, 21 cyclists; 11 male (VO: 57 ± 9 mL·kg·min) and 10 female (VO: 51 ± 9 mL·kg·min), completed 45 min of fixed, moderate-intensity (discontinuous) cycling followed by an incremental ride to exhaustion. Cognitive function was assessed at Baseline, after 15 and 45 min of exercise (15EX and 45EX) and at Exhaustion using a 4-Choice Reaction Time (CRT) test and the Stroop test (Incongruent and Congruent Reaction Time [RT]). A sham capsule was administered on one occasion to determine whether the cognitive response to exercise was robust to the influence of a placebo. CRT, Congruent RT and Incongruent RT decreased (improved) at 15EX, 45EX and Exhaustion compared to Baseline ('s<0.005). While CRT and Congruent RT were faster at 45EX than 15EX ('s<0.020), Incongruent RT was not (= 1.000). The sham treatment did not affect cognition. When performed at a moderate-intensity, longer duration exercise (up to 45 min) may improve cognition to a greater extent than shorter duration exercise; however, the magnitude of improvement appears to decrease with increasing task complexity. HI/EE performed following a sustained bout of dehydrating activity may not impair cognition.
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http://dx.doi.org/10.1080/02640414.2020.1809976DOI Listing
January 2021

The effect of cannabidiol on simulated car driving performance: A randomised, double-blind, placebo-controlled, crossover, dose-ranging clinical trial protocol.

Hum Psychopharmacol 2020 09 29;35(5):e2749. Epub 2020 Jul 29.

Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, New South Wales, Australia.

Objective: Interest in the use of cannabidiol (CBD) is increasing worldwide as its therapeutic effects are established and legal restrictions moderated. Unlike Δ -tetrahydrocannabinol (Δ -THC), CBD does not appear to cause cognitive or psychomotor impairment. However, further assessment of its effects on cognitively demanding day-to-day activities, such as driving, is warranted. Here, we describe a study investigating the effects of CBD on simulated driving and cognitive performance.

Methods: Thirty healthy individuals will be recruited to participate in this randomised, double-blind, placebo-controlled crossover trial. Participants will complete four research sessions each involving two 30-min simulated driving performance tests completed 45 and 210 min following oral ingestion of placebo or 15, 300, or 1,500 mg CBD. Cognitive function and subjective drug effects will be measured, and blood and oral fluid sampled, at regular intervals. Oral fluid drug testing will be performed using the Securetec DrugWipe® 5S and Dräger DrugTest® 5000 devices to determine whether CBD increases the risk of "false-positive" roadside tests to Δ -THC. Noninferiority analyses will test the hypothesis that CBD is no more impairing than placebo.

Conclusion: This study will clarify the risks involved in driving following CBD use and assist in ensuring the safe use of CBD by drivers.
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http://dx.doi.org/10.1002/hup.2749DOI Listing
September 2020

Cannabidiol and Sports Performance: a Narrative Review of Relevant Evidence and Recommendations for Future Research.

Sports Med Open 2020 Jul 6;6(1):27. Epub 2020 Jul 6.

The University of Sydney, Faculty of Science, School of Psychology, Sydney, New South Wales, 2050, Australia.

Cannabidiol (CBD) is a non-intoxicating cannabinoid derived from Cannabis sativa. CBD initially drew scientific interest due to its anticonvulsant properties but increasing evidence of other therapeutic effects has attracted the attention of additional clinical and non-clinical populations, including athletes. Unlike the intoxicating cannabinoid, Δ-tetrahydrocannabinol (Δ-THC), CBD is no longer prohibited by the World Anti-Doping Agency and appears to be safe and well-tolerated in humans. It has also become readily available in many countries with the introduction of over-the-counter "nutraceutical" products. The aim of this narrative review was to explore various physiological and psychological effects of CBD that may be relevant to the sport and/or exercise context and to identify key areas for future research. As direct studies of CBD and sports performance are is currently lacking, evidence for this narrative review was sourced from preclinical studies and a limited number of clinical trials in non-athlete populations. Preclinical studies have observed robust anti-inflammatory, neuroprotective and analgesic effects of CBD in animal models. Preliminary preclinical evidence also suggests that CBD may protect against gastrointestinal damage associated with inflammation and promote healing of traumatic skeletal injuries. However, further research is required to confirm these observations. Early stage clinical studies suggest that CBD may be anxiolytic in "stress-inducing" situations and in individuals with anxiety disorders. While some case reports indicate that CBD improves sleep, robust evidence is currently lacking. Cognitive function and thermoregulation appear to be unaffected by CBD while effects on food intake, metabolic function, cardiovascular function, and infection require further study. CBD may exert a number of physiological, biochemical, and psychological effects with the potential to benefit athletes. However, well controlled, studies in athlete populations are required before definitive conclusions can be reached regarding the utility of CBD in supporting athletic performance.
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http://dx.doi.org/10.1186/s40798-020-00251-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7338332PMC
July 2020

Effects of probiotics and paraprobiotics on subjective and objective sleep metrics: a systematic review and meta-analysis.

Eur J Clin Nutr 2020 11 20;74(11):1536-1549. Epub 2020 May 20.

Physical Activity Research Group, Appleton Institute & School of Health Medical and Applied Sciences, Central Queensland University, Brisbane, QLD, Australia.

Inadequate sleep (i.e., duration and/or quality) is becoming increasingly recognized as a global public health issue. Interaction via the gut-brain axis suggests that modification of the gut microbial environment via supplementation with live microorganisms (probiotics) or nonviable microorganisms/microbial cell fractions (paraprobiotics) may improve sleep health. This systematic review and meta-analysis aimed to clarify the effect of consuming probiotics/paraprobiotics on subjective and objective sleep metrics. Online databases were searched from 1980 to October 2019 for studies involving adults who consumed probiotics or paraprobiotics in controlled trials, during which, changes in subjective and/or objective sleep parameters were examined. A total of 14 studies (20 trials) were included in meta-analysis. Random effects meta-analyses indicated that probiotics/paraprobiotics supplementation significantly reduced Pittsburgh Sleep Quality Index (PSQI) score (i.e., improved sleep quality) relative to baseline (-0.78-points, 95% confidence interval: 0.395-1.166; p < 0.001). No significant effect was found for changes on other subjective sleep scales, nor objective parameters of sleep (efficiency/latency) measured using polysomnography or actigraphy. Subgroup analysis for PSQI data suggested that the magnitude of the effect was greater (although not statistically) in healthy participants than those with a medical condition, when treatment contained a single (rather than multiple) strain of probiotic bacteria, and when the duration of treatment was ≥8 weeks. Probiotics/paraprobiotics supplementation may have some efficacy in improving perceived sleep health, measured using the PSQI. While current evidence does not support a benefit of consuming probiotics/paraprobiotics when measured by other subjective sleep scales, nor objective measures of sleep; more studies using well-controlled, within-subject experimental designs are needed.
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http://dx.doi.org/10.1038/s41430-020-0656-xDOI Listing
November 2020

Consumption of a smoothie or cereal-based breakfast: impact on thirst, hunger, appetite and subsequent dietary intake.

Int J Food Sci Nutr 2021 Feb 18;72(1):123-133. Epub 2020 May 18.

School of Allied Health Sciences and Menzies Health Institute Queensland, Griffith University, Gold Coast, Australia.

Smoothies are a popular breakfast option. However, liquids may evoke weaker satiation than nutritionally comparable semi-solid and solid foods. This study examined consumption of cereal and milk (CM) or a nutritionally comparable fruit smoothie (FS) for breakfast on subsequent dietary behaviours, in a controlled laboratory setting. Twenty-five participants (age 25 ± 6 y) completed three trials, receiving either CM or FS for breakfast. Afterwards, participants remained isolated for 4 h with access to foods/beverages. A repeat trial (CM or FS) allowed exploration of normal variability. Post-breakfast energy intake (EI) (CM = 1465(2436) vs. FS = 1787(3190) kJ, Median (IQR),  = 0.099), time to intake of next food/fluid (meal latency) (CM = 146(97) vs. FS = 180(100) min,  = 0.127), and subjective hunger, desire to eat, fullness and thirst ratings were similar between conditions ( > 0.05). The mean coefficient of variation for EI and meal latency were 41% and 21%, respectively. Consumption of a FS does not negatively impact acute EI and meal latency.
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http://dx.doi.org/10.1080/09637486.2020.1767041DOI Listing
February 2021

Effects of Diet on Sleep: A Narrative Review.

Nutrients 2020 Mar 27;12(4). Epub 2020 Mar 27.

Central Queensland University, School of Health, Medical and Applied Sciences and Appleton Institute, Brisbane 4000, Queensland, Australia.

Many processes are involved in sleep regulation, including the ingestion of nutrients, suggesting a link between diet and sleep. Aside from studies investigating the effects of tryptophan, previous research on sleep and diet has primarily focused on the effects of sleep deprivation or sleep restriction on diet. Furthermore, previous reviews have included subjects with clinically diagnosed sleep-related disorders. The current narrative review aimed to clarify findings on sleep-promoting foods and outline the effects of diet on sleep in otherwise healthy adults. A search was undertaken in August 2019 from the Cochrane, MEDLINE (PubMed), and CINAHL databases using the population, intervention, control, outcome (PICO) method. Eligible studies were classified based on emerging themes and reviewed using narrative synthesis. Four themes emerged: tryptophan consumption and tryptophan depletion, dietary supplements, food items, and macronutrients. High carbohydrate diets, and foods containing tryptophan, melatonin, and phytonutrients (e.g., cherries), were linked to improved sleep outcomes. The authors posit that these effects may be due in part to dietary influences on serotonin and melatonin activity.
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http://dx.doi.org/10.3390/nu12040936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230229PMC
March 2020

Effects of acute caffeine consumption following sleep loss on cognitive, physical, occupational and driving performance: A systematic review and meta-analysis.

Neurosci Biobehav Rev 2020 01 16;108:877-888. Epub 2019 Dec 16.

School of Allied Health Sciences, Griffith University, Gold Coast, Australia.

Caffeine is widely used to counteract the effects of sleep loss. This systematic review and meta-analysis examined the impact of acute caffeine consumption on cognitive, physical, occupational and driving performance in sleep deprived/restricted individuals. 45 publications providing 327 effect estimates (EEs) were included in the review. Caffeine improved response time (44 EEs; g = 0.86; 95 % CI: 0.53-0.83) and accuracy (27 EEs; g = 0.68; 95 % CI: 0.48-0.88) on attention tests, improved executive function (38 EEs; g = 0.35; 95 % CI: 0.15-0.55), improved reaction time (12 EEs; g = 1.11; 95 % CI: 0.75-1.47), improved response time (20 EEs; g = 1.95; 95 % CI: 1.39-2.52) and accuracy (34 EEs; g = 0.43; 95 % CI: 0.30-0.55) on information processing tasks, and enhanced lateral (29 EEs; g = 1.67; 95 % CI: 1.32-2.02) and longitudinal (12 EEs; g = 1.60; 95 % CI: 1.16-2.03) measures of vehicular control on driving tests. Studies also typically indicated benefit of caffeine on memory (25 EEs), crystallized intelligence (11 EEs), physical (39 EEs) and occupational (36 EEs) performance. Ingestion of caffeine is an effective counter-measure to the cognitive and physical impairments associated with sleep loss.
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http://dx.doi.org/10.1016/j.neubiorev.2019.12.008DOI Listing
January 2020

Effect of Drinking Rate on the Retention of Water or Milk Following Exercise-Induced Dehydration.

Int J Sport Nutr Exerc Metab 2019 Dec 4:1-11. Epub 2019 Dec 4.

Griffith University.

This study investigated the effect of drinking rate on fluid retention of milk and water following exercise-induced dehydration. In Part A, 12 male participants lost 1.9% ± 0.3% body mass through cycle exercise on four occasions. Following exercise, plain water or low-fat milk equal to the volume of sweat lost during exercise was provided. Beverages were ingested over 30 or 90 min, resulting in four beverage treatments: water 30 min, water 90 min, milk 30 min, and milk 90 min. In Part B, 12 participants (nine males and three females) lost 2.0% ± 0.3% body mass through cycle exercise on four occasions. Following exercise, plain water equal to the volume of sweat lost during exercise was provided. Water was ingested over 15 min (DR15), 45 min (DR45), or 90 min (DR90), with either DR15 or DR45 repeated. In both trials, nude body mass, urine volume, urine specific gravity and osmolality, plasma osmolality, and subjective ratings of gastrointestinal symptoms were obtained preexercise and every hour for 3 hr after the onset of drinking. In Part A, no effect of drinking rate was observed on the proportion of fluid retained, but milk retention was greater (p < .01) than water (water 30 min: 57% ± 16%, water 90 min: 60% ± 20%, milk 30 min: 83% ± 6%, and milk 90 min: 85% ± 7%). In Part B, fluid retention was greater in DR90 (57% ± 13%) than DR15 (50% ± 11%, p < .05), but this was within test-retest variation determined from the repeated trials (coefficient of variation: 17%). Within the range of drinking rates investigated the nutrient composition of a beverage has a more pronounced impact on fluid retention than the ingestion rate.
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http://dx.doi.org/10.1123/ijsnem.2019-0176DOI Listing
December 2019

Effects of alcohol intoxication goggles (fatal vision goggles) with a concurrent cognitive task on simulated driving performance.

Traffic Inj Prev 2019 14;20(8):777-782. Epub 2019 Nov 14.

School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia.

Fatal vision goggles (FVGs) are image-distorting equipment used to simulate alcohol impairment in driver education programs. Unlike alcohol, which disrupts cognitive processes, FVG only induces visual impairment. Performing concurrent cognitive tasks while wearing FVG may reduce the wearer's attentional resources and provide a better simulation of alcohol intoxication. This study examined the impact of wearing FVG with/without administration of a concurrent cognitive task on simulated driving. Twenty-one males (23 ± 3 y, mean ± SD) participated in this randomized, repeated-measures study involving two experimental trials. In each trial, participants completed a baseline drive then an experimental drive under one of two conditions: (1) FVG and (2) FVG with additional cognitive demand (FVG + CD). The driving test included 3 separate scenarios (Task 1, 2, 3) lasting ∼5min each. Lateral (standard deviation of lane position [SDLP]; number of lane crossings [LCs]) and longitudinal control parameters (average speed; standard deviation of speed [SDSP]; distance headway; minimum distance headway) were monitored in Tasks 1 and 2. Latency to two different stimuli (choice reaction time [CRT]) was examined in Task 3. In Task 1, SDLP and LC were unaffected by either condition. However, SDSP increased significantly from baseline with FVG, irrespective of cognitive demand. In Task 2, distance headway decreased significantly from baseline with FVG, but increased significantly with FVG + CD. Minimum distance headway was significantly decreased, while SDLP increased significantly and LC increased (although not statistically significant) in both conditions relative to baseline. In Task 3, a significant increase in CRT occurred with FVG + CD, but not with FVG alone. Wearing FVG negatively impacted simulated driving performance. However, effects were isolated to specific performance outcomes and were dependent on complexity of the driving task. Addition of a secondary cognitive task exacerbates the effects of FVG on select driving outcomes (i.e. lane position, SDSP), influences the effect direction on other measures (i.e. distance headway), and has a detrimental effect on reaction time to stimuli embedded in the scenario, that is not observed with FVG alone. Future studies using FVG as a surrogate means to alcohol intoxication should consider these results, informing methodological decisions to reduce potential for confounding effects.
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http://dx.doi.org/10.1080/15389588.2019.1669023DOI Listing
July 2020

Sensitive and Reliable Measures of Driver Performance in Simulated Motor-Racing.

Int J Exerc Sci 2019 1;12(6):971-978. Epub 2019 Aug 1.

School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, AUSTRALIA.

Motor racing is a physically and mentally demanding sport, associated with a high degree of risk for drivers. Hence, driving simulation provides a safe alternative to explore the impact acute physiological perturbations (e.g. heat stress or dehydration) on a driver's performance. This study aimed to determine sensitive and reliable simulated driving performance parameters that could be employed in future driving performance studies. Thirty-six healthy males (age: 26.5 ± 8.1 y, body mass: 75.6 ± 12.2 kg, mean ± SD) completed a single experimental trial involving four simulated motor-racing drives (2 initial drives and 2 repeat drives) separated by a 1 h period. Drives were conducted under two conditions, with one condition (wearing Fatal Vision Goggles (FVG)) designed to impair driving performance by distorting vision. Sensitivity was assessed by comparing Normal vs FVG outcomes and reliability was determined by comparing initial vs repeat drives for the same condition. Measures of driving performance included lap time (LT), sector-time (ST) for one section of the track, position displacement to a marker on the first track corner (PD), and vehicle Speed at PD. Results indicated that LT and ST were reliable and sensitive performance measures to a visual disturbance. However, PD was neither sensitive nor reliable and Speed at PD was not sensitive as driving performance measures to the study conditions. Overall, this study demonstrates two sensitive and reliable performance measures (LT and ST) that can be used to assess simulated motor-racing performance in future investigations.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6719813PMC
August 2019

No Impact of Heat Stress and Dehydration on Short Duration Simulated Motor-Racing Performance.

Int J Exerc Sci 2019 1;12(6):960-970. Epub 2019 Aug 1.

School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, AUSTRALIA.

Motor-racing drivers are often exposed to hot environments and may be susceptible to fluid loss and hydration issues, which could influence driving performance. This study assessed the effect of dehydration and heat stress on performance during a short, simulated motor-racing task. Nine healthy males (age: 26.6 ± 7.5 y, body mass: 78.8 ± 12.5 kg, mean ± SD) completed two passive dehydration (sauna) procedures (targeting -1% and -3% body mass loss (BML)) on separate occasions. Driving performance was assessed pre-dehydration (Baseline), immediately post-dehydration (Hot) and following a cooling period (Cool). Measures of driving performance included lap time and sector-time for one section of the track. Subjective ratings of mood, thermal stress and comfort were also collected during trials. Mean lap times were not different between Baseline, Hot, Cool conditions for both 1% (68.44 ± 1.43 s, 68.06 ± 1.17 s, 68.23 ± 1.25 s) and 3% (68.33 ± 1.68 s, 68.01 ± 1.15 s, 68.06 ± 1.26 s) trials respectively. In addition, mean sector times were not different between Baseline, Hot, Cool conditions for both 1% (11.61 ± 0.28 s, 11.55 ± 0.45 s, 11.59 ± 0.35 s) and 3% (11.49 ± 0.33 s, 11.56 ± 0.33 s, 11.63 ± 0.71 s) trials respectively. Changes in participants' subjective ratings (i.e. decreased alertness, concentration and comfort; increased tiredness and light-headedness) were observed at both levels of dehydration (1% and 3% BML), irrespective of heat stress. Thus, fluid loss and heat stress are unlikely to affect driver's motor-racing performance during short duration events. However, the impact of dehydration and heat stress on tasks of longer duration that accurately represent the demands associated with motor-racing requires further consideration.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6719815PMC
August 2019

Association between dietary patterns and sociodemographics: A cross-sectional study of Australian nursing students.

Nurs Health Sci 2020 Mar 30;22(1):38-48. Epub 2019 Aug 30.

Appleton Institute, School of Health Medical and Applied Sciences, Brisbane, Queensland, Australia.

Lack of time, financial issues, and stressful clinical and educational environments in nursing studies promote higher intakes of convenience and fast foods loaded with fat and sugar, which are linked to reduced mental and physical health. In this study, we examined the dietary patterns of nursing students and their associated sociodemographic factors to inform the development of future health-promotion interventions. A total of 548 Bachelor of Nursing students were invited to complete a survey. Associations were explored using χ and logistic regression. Three dietary patterns were identified: healthy (fruit, vegetables, and legumes), Western (loaded with fat, sugar, and salt), and unbalanced. Only 21% of participants were classified as following a healthy dietary pattern, and more likely to be older (>35 years old) and have a personal annual income between $AUD20 000-$59 999 and $60 000-$99 999. Students with one to two and three or more children were more likely to follow a Western dietary pattern. There is a need to develop interventions to improve the dietary behaviors of nursing students by health-promoting activities and the provision of online health resources.
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http://dx.doi.org/10.1111/nhs.12643DOI Listing
March 2020

Tattoos do not affect exercise-induced localised sweat rate or sodium concentration.

J Sci Med Sport 2019 Nov 19;22(11):1249-1253. Epub 2019 Jun 19.

School of Allied Health Sciences, Griffith University, Australia. Electronic address:

Objectives: Skin tattoos have been shown to reduce localised sweat rate and increase sweat sodium concentration ([Na]) when sweating is artificially stimulated. This study investigated whether similar responses are observed with exercise-induced sweating.

Design: Unblinded, within-participant control, single trial.

Methods: Twenty-two healthy individuals (25.1±4.8 y (Mean±SD), 14 males) with a unilateral tattoo ≥11.4cm in size, ≥2 months in age, and shaded ≥50% participated in this investigation. Participants undertook 20min of intermittent cycling (4×5min intervals) on a stationary ergometer in a controlled environment (24.6±1.1°C; 64±6% RH). Resultant sweat was collected into absorbent patches applied at two pairs of contralateral skin sites (pair 1: Tattoo vs. Non-Tattoo; pair 2: Control 1 vs. Control 2 (both non-tattooed)), for determination of sweat rate and sweat [Na]. Paired samples t-tests were used to determine differences between contralateral sites.

Results: Tattoo vs. Non-Tattoo: Neither sweat rate (Mean±SD: 0.92±0.37 vs. 0.94±0.43mg·cm·min, respectively; p=0.693) nor sweat [Na] (Median(IQR): 37(32-52) vs. 37(31-45) mM·L, respectively; p=0.827) differed. Control 1 vs. Control 2: Neither sweat rate (Mean±SD: 1.19±0.53 vs. 1.19±0.53mg·cm·min, respectively; p=0.917) nor sweat [Na] (Median(IQR): 29(26-41) vs. 31(25-43)mM·L, respectively; p=0.147) differed. The non-significant differences for sweat rate and [Na] between Tattoo vs. Non-Tattoo were inside the range of the within participant variability (sweat rate CVi=5.4%; sweat [Na] CVi=4.4%).

Conclusions: Skin tattoos do not appear to alter the rate or [Na] of exercise-induced sweating. The influence of skin tattoos on localised sweat responses may have previously been over-estimated.
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http://dx.doi.org/10.1016/j.jsams.2019.06.004DOI Listing
November 2019

Cannabidiol (CBD) content in vaporized cannabis does not prevent tetrahydrocannabinol (THC)-induced impairment of driving and cognition.

Psychopharmacology (Berl) 2019 Sep 1;236(9):2713-2724. Epub 2019 May 1.

Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Sydney, New South Wales, Australia.

Background: The main psychoactive component of cannabis, delta-9-tetrahydrocannabinol (THC), can impair driving performance. Cannabidiol (CBD), a non-intoxicating cannabis component, is thought to mitigate certain adverse effects of THC. It is possible then that cannabis containing equivalent CBD and THC will differentially affect driving and cognition relative to THC-dominant cannabis.

Aims: The present study investigated and compared the effects of THC-dominant and THC/CBD equivalent cannabis on simulated driving and cognitive performance.

Methods: In a randomized, double-blind, within-subjects crossover design, healthy volunteers (n = 14) with a history of light cannabis use attended three outpatient experimental test sessions in which simulated driving and cognitive performance were assessed at two timepoints (20-60 min and 200-240 min) following vaporization of 125 mg THC-dominant (11% THC; < 1% CBD), THC/CBD equivalent (11% THC, 11% CBD), or placebo (< 1% THC/CBD) cannabis.

Results/outcomes: Both active cannabis types increased lane weaving during a car-following task but had little effect on other driving performance measures. Active cannabis types impaired performance on the Digit Symbol Substitution Task (DSST), Divided Attention Task (DAT) and Paced Auditory Serial Addition Task (PASAT) with impairment on the latter two tasks worse with THC/CBD equivalent cannabis. Subjective drug effects (e.g., "stoned") and confidence in driving ability did not vary with CBD content. Peak plasma THC concentrations were higher following THC/CBD equivalent cannabis relative to THC-dominant cannabis, suggesting a possible pharmacokinetic interaction.

Conclusions/interpretation: Cannabis containing equivalent concentrations of CBD and THC appears no less impairing than THC-dominant cannabis, and in some circumstances, CBD may actually exacerbate THC-induced impairment.
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http://dx.doi.org/10.1007/s00213-019-05246-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6695367PMC
September 2019

Challenges following a personalised diet adhering to dietary guidelines in a sample of Australian university students.

Nutr Health 2019 Sep 11;25(3):185-194. Epub 2019 Apr 11.

School of Allied Health Sciences, Griffith University, Gold Coast, Australia.

Background: Food-based dietary guidelines are designed to support populations to adopt a healthy diet. University students studying nutrition related courses are typically en-route to professional roles that involve advocating a healthy diet.

Aim: The present study compared the dietary intake of university students enrolled in a foundation nutrition course against the Australian Dietary Guidelines (ADGs) and Nutrient Reference Values (NRVs), and explored students' experiences of following a 3-day self-determined diet plan adhering to the ADGs/NRVs.

Methods: Students ( = 115) initially collected, and subsequently analysed a 3-day prospective diet record to determine food group/nutrient intake. Individuals then modified their diet to comply with recommendations (ADGs/NRVs) and attempted to implement the diet plan. Challenges associated with meeting the ADGs/NRVs were described in an online survey form.

Results: Baseline food group and nutrient intakes deviated from the guidelines, with 'lean meats & alternatives' the only group consumed in recommended quantities. Students demonstrated the capacity to plan a modified personal diet adhering to the ADGs food group recommendations. However, when following this, several key challenges to dietary adherence were identified. Challenges were categorised as personal/behavioural factors (e.g. the quantity/type of food) and societal factors (e.g. time, cost, social factors).

Conclusion: Overall, this study highlights challenges influencing adherence to dietary guidelines in a sample of undergraduate university students. Understanding these factors may help tailor advice to facilitate improved dietary patterns in this population group.
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http://dx.doi.org/10.1177/0260106019841247DOI Listing
September 2019

The influence of a fruit smoothie or cereal and milk breakfast on subsequent dietary intake: a pilot study.

Int J Food Sci Nutr 2019 Aug 2;70(5):612-622. Epub 2019 Jan 2.

a School of Allied Health Sciences , Griffith University , Southport , Australia.

Smoothies are popular breakfast foods. This study examined the effect of consuming Cereal & Milk (CM) or a nutritionally-comparable Fruit Smoothie (FS) for breakfast on daily energy intake (EI) in free-living adults and the extent to which individuals compensated for calories ingested in a High Energy Fruit Smoothie (HE). Ten participants (28.4 ± 2.2y; 23.3 ± 1.0 kg·m , Mean ± SEM) attended the laboratory on 3 consecutive days per week for 3 weeks. Each week, they received a CM, FS or HE breakfast, then recorded all food/beverages consumed across the remainder of the day. The CM and FS were energy-matched to participants' usual breakfast (1675 ± 283 kJ), while the HE contained an additional 100 kJ·kg of maltodextrin (3019 ± 335 kJ). Mean 3-day EI was similar on CM and FS (7894 ± 547 vs. 7570 ± 463 kJ,  > .05), but elevated on HE (8861 ± 726 kJ,  =  .012). Thus, individuals who substitute CM for a FS breakfast should be mindful that energy-dense beverages may result in increased daily EI.
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http://dx.doi.org/10.1080/09637486.2018.1547690DOI Listing
August 2019

The effect of different post-exercise beverages with food on ad libitum fluid recovery, nutrient provision, and subsequent athletic performance.

Physiol Behav 2019 03 13;201:22-30. Epub 2018 Dec 13.

School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia.

This study investigated the effect of consuming either water or a carbohydrate (CHO)-electrolyte sports beverage ('Sports Drink') ad libitum with food during a 4 h post-exercise recovery period on fluid restoration, nutrient provision and subsequent endurance cycling performance. On two occasions, 16 endurance-trained cyclists; 8 male [M] (age: 31 ± 9 y; VO: 54 ± 6 mL·kg·min) and 8 female [F] (age: 33 ± 8 y; VO: 50 ± 7 mL·kg·min); lost 2.3 ± 0.3% and 1.6 ± 0.3% of their body mass (BM), respectively during 1 h of fixed-intensity cycling. Participants then had ad libitum access to either Water or Sports Drink and food for the first 195 min of a 4 h recovery period. At the conclusion of the recovery period, participants completed a cycling performance test consisting of a 45 min fixed-intensity pre-load and an incremental test to volitional exhaustion (peak power output, PPO). Beverage intake; total water/nutrient intake; and indicators of fluid recovery (BM, urine output, plasma osmolality [P]) were assessed periodically throughout trials. Participants returned to a similar state of net positive fluid balance prior to recommencing exercise, regardless of the beverage provided (Water: +0.4 ± 0.5 L; Sports Drink: +0.3 ± 0.3 L, p = 0.529). While Sports Drink increased post-exercise energy (M: +1.8 ± 1.0 MJ; F: +1.3 ± 0.5 MJ) and CHO (M: +114 ± 31 g; F: +84 ± 25 g) intake (i.e. total from food and beverage) (p's < 0.001), this did not improve subsequent endurance cycling performance (Water: 337 ± 40 W [M] and 252 ± 50 W [F]; Sports Drink: 340 ± 40 W [M] and 258 ± 47 W [F], p = 0.242). Recovery beverage recommendations should consider the post-exercise environment (i.e. the availability of food), an individual's tolerance for food and fluid pre-/post-exercise, the immediate requirements for refuelling (i.e. CHO demands of the activity) and the athlete's overall dietary goals.
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http://dx.doi.org/10.1016/j.physbeh.2018.12.013DOI Listing
March 2019

Caffeine content of Nespresso® pod coffee.

Nutr Health 2019 Mar 5;25(1):3-7. Epub 2018 Nov 5.

1 School of Allied Health Sciences, Griffith University, Australia.

Background:: Little independent information on the caffeine content of the popular Nespresso coffee pod range exists.

Aim:: To quantify the caffeine content of Nespresso pod coffees.

Methods:: Initially, three serves (ristretto (S), espresso (M), lungo (L)) of two pod varieties (Livanto and Roma) were prepared on three different Nespresso machines (2 × U-Delonghi (1 × 5 years since purchase (old), 1 × recently purchased (new)), 1 × new Lattissima Pro (alternate)) using two different batches (sleeves). Caffeine content was then determined via triplicate samples using high-performance liquid chromatography. Differences in content (i.e. serve size, machine or sleeve) were determined via an analysis of variance or paired sample t-tests.

Results:: Coffees prepared on different machines or pods from different sleeves did not influence the caffeine content (old = 63 ± 13, new = 60 ± 8, alternate = 60 ± 10 mg·serve; p = 0.537, sleeveA = 63 ± 11, sleeveB = 59 ± 9 mg·serve; p = 0.134). Less caffeine was delivered in S (51 ± 7 mg·serve) compared to larger sizes (M = 66 ± 7 and L = 66 ± 10 mg·serve). Subsequently, the caffeine content from two serve sizes (S and L) from 17 other varieties within the Nespresso range was determined and compared to the manufacturer's values. Caffeine content (all pods) ranged from 19 to 147 mg·serve, and represented 51-162% of manufacturer's values.

Conclusion:: Nespresso consumers are exposed to variable amounts of caffeine, which often differ from the manufacturer's reports.
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http://dx.doi.org/10.1177/0260106018810941DOI Listing
March 2019

Fluid, energy, and nutrient recovery via ad libitum intake of different commercial beverages and food in female athletes.

Appl Physiol Nutr Metab 2019 Jan 28;44(1):37-46. Epub 2018 Jun 28.

a School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, 4215, Australia.

This study investigated the effect of consuming different commercial beverages with food ad libitum after exercise on fluid, energy, and nutrient recovery in trained females. On 4 separate occasions, 8 females (body mass (BM): 61.8 ± 10.7 kg; maximal oxygen uptake: 46.3 ± 7.5 mL·kg·min) lost 2.0% ± 0.3% BM cycling at ∼75% maximal oxygen uptake before completing a 4-h recovery period with ad libitum access to 1 of 4 beverages: Water, Powerade (Sports Drink), Up & Go Reduced Sugar (Lower Sugar (LS)-MILK) or Up & Go Energize (Higher Protein (HP)-MILK). Participants also had two 15-min opportunities to access food within the first 2 h of the recovery period. Beverage intake, total water/nutrient intake, and indicators of fluid recovery (BM, urine output, plasma osmolality), gastrointestinal tolerance and palatability were assessed periodically. While total water intake (from food and beverage) (Water: 1918 ± 580 g; Sports Drink: 1809 ± 338 g; LS-MILK: 1458 ± 431 g; HP-MILK: 1523 ± 472 g; p = 0.010) and total urine output (Water: 566 ± 314 g; Sports Drink: 459 ± 290 g; LS-MILK: 220 ± 53 g; HP-MILK: 230 ± 117 g; p = 0.009) differed significantly by beverage, the quantity of ingested water retained was similar across treatments (Water: 1352 ± 462 g; Sports Drink: 1349 ± 407 g; LS-MILK: 1238 ± 400 g; HP-MILK: 1293 ± 453 g; p = 0.691). Total energy intake (from food and beverage) increased in proportion to the energy density of the beverage (Water: 4129 ± 1080 kJ; Sports Drink: 5167 ± 643 kJ; LS-MILK: 6019 ± 1925 kJ; HP-MILK: 7096 ± 2058 kJ; p = 0.014). When consumed voluntarily and with food, different beverages promote similar levels of fluid recovery, but alter energy/nutrient intakes. Providing access to food and understanding the longer-term dietary goals of female athletes are important considerations when recommending a recovery beverage.
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http://dx.doi.org/10.1139/apnm-2018-0176DOI Listing
January 2019