The effect of contact/collision sport participation without concussion on neurometabolites: A systematic review and meta-analysis of magnetic resonance spectroscopy studies.

The aim of this study was to systematically review prior research investigating the effects of contact/collision sport participation on neurometabolite levels in the absence of concussion. Four online databases were searched to identify studies that measured neurometabolite levels in contact/collision sport athletes (without concussion) using proton (1 H) or phosphorus (31 P) magnetic resonance spectroscopy (MRS). All study designs were acceptable for inclusion. Meta-analytic procedures were used to quantify the effect of contact/collision sport participation on neurometabolite levels and explore the impact of specific moderating factors (where sufficient data were available). Narrative synthesis was used to describe outcomes that could not be meta-analysed. Nine observational studies involving 300 contact/collision sport athletes were identified. Six studies (providing 112 effect estimates) employed longitudinal (cohort) designs and three (that could not be meta-analysed) employed case-control designs. N-acetylaspartate (NAA; g = -0.331, p = 0.013) and total creatine (tCr; creatine + phosphocreatine; g = -0.524, p = 0.029), but not glutamate-glutamine (Glx), myo-inositol (mI) or total choline (tCho; choline-containing compounds; p's > 0.05), decreased between the pre-season and mid-/post-season period. Several moderators were statistically significant, including: sex (Glx: 6 female/23 male, g = -0.549, p = 0.013), sport played (Glx: 22 American football/4 association football [soccer], g = 0.724, p = 0.031), brain region (mI: 2 corpus callosum/9 motor cortex, g = -0.804, p = 0.015), and the MRS quantification approach (mI: 18 absolute/3 tCr-referenced, g = 0.619, p = 0.003; and tCho: 18 absolute/3 tCr-referenced, g = 0.554, p = 0.005). In case-control studies, contact/collision sport athletes had higher levels of mI, but not NAA or tCr compared to non-contact sport athletes and non-athlete controls. Overall, this review suggests that contact/collision sport participation has the potential to alter neurometabolites measured via 1 H MRS in the absence of concussion. However, further research employing more rigorous and consistent methodologies (e.g. interventional studies with consistent 1 H MRS pulse sequences and quantifications) is required to confirm and better understand the clinical relevance of observed effects.

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

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.

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

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.

Assessment of an integrated knowledge translation intervention to improve nutrition intakes among patients undergoing elective bowel surgery: a mixed-method process evaluation.

BACKGROUND: A large evidence-practice gap exists regarding provision of nutrition to patients following surgery. The aim of this study was to evaluate the processes supporting the implementation of an intervention designed to improve the timing and adequacy of nutrition following bowel surgery. METHODS: A mixed-method pilot study, using an integrated knowledge translation (iKT) approach, was undertaken at a tertiary teaching hospital in Australia. A tailored, multifaceted intervention including ten strategies targeted at staff or patients were co-developed with knowledge users at the hospital and implemented in practice. Process evaluation outcomes included reach, intervention delivery and staffs' responses to the intervention. Quantitative data, including patient demographics and surgical characteristics, intervention reach, and intervention delivery were collected via chart review and direct observation. Qualitative data (responses to the intervention) were sequentially collected from staff during one-on-one, semi-structured interviews. Quantitative data were summarized using median (IQR), mean (SD) or frequency(%), while qualitative data were analysed using content analysis. RESULTS: The intervention reached 34 patients. Eighty-four percent of nursing staff received an awareness and education session, while 0% of medical staff received a formal orientation or awareness and education session, despite the original intention to deliver these sessions. Several strategies targeted at patients had high fidelity, including delivery of nutrition education (92%); and prescription of oral nutrition supplements (100%) and free fluids immediately post-surgery (79%). Prescription of a high energy high protein diet on postoperative day one (0%) and oral nutrition supplements on postoperative day zero (62%); and delivery of preoperative nutrition handout (74%) and meal ordering education (50%) were not as well implemented. Interview data indicated that staff regard nutrition-related messages as important, however, their acceptance, awareness and perceptions of the intervention were mixed. CONCLUSIONS: Approximately half the patient-related strategies were implemented well, which is likely attributed to the medical and nursing staff involved in intervention design championing these strategies. However, some strategies had low delivery, which was likely due to the varied awareness and acceptance of the intervention among staff on the ward. These findings suggest the importance of having buy-in from all staff when using an iKT approach to design and implement interventions.

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

The cognitive effects of acute aerobic exercise were investigated in endurance-trained individuals. On two occasions, 21 cyclists; 11 male (VO2max: 57 ± 9 mL·kg-1·min-1) and 10 female (VO2max: 51 ± 9 mL·kg-1·min-1), 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 (p's<0.005). While CRT and Congruent RT were faster at 45EX than 15EX (p's<0.020), Incongruent RT was not (p= 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.

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

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 ad libitum 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), p = 0.099), time to intake of next food/fluid (meal latency) (CM = 146(97) vs. FS = 180(100) min, p = 0.127), and subjective hunger, desire to eat, fullness and thirst ratings were similar between conditions (p's > 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.

Engaging hospitalised patients in their nutrition care using technology: development of the NUTRI-TEC intervention.

BACKGROUND: Nutrition is vital for health and recovery during hospitalisation, however most patients fail to meet minimum dietary requirements and up to 50% of patients are malnourished in hospital. When patients participate in nutrition care, their dietary intakes are improved. Advances in health information technology (HIT) have broadened the ways by which patients can participate in care. Our team has developed an innovative, HIT-based intervention (called NUTRI-TEC; engaging patients in their nutrition care using technology), facilitating patient participation in their nutrition care in hospital. This paper aims to describe the systematic and iterative process by which the intervention was developed. METHODS: NUTRI-TEC development was informed by the Medical Research Council guidance for developing complex interventions and underpinned by theoretical frameworks and concepts (i.e. integrated knowledge translation and patient participation in care), existing evidence and a rigorous program of research. The intervention was co-developed by the multidisciplinary research team and stakeholders, including health consumers (patients), health professionals and industry partners. We used an iterative development and evaluation cycle and regularly tested the intervention with hospital patients and clinicians. RESULTS: The NUTRI-TEC intervention involves active patient participation in their nutrition care during hospitalisation. It has two components: 1) Patient education and training; and 2) Guided nutrition goal setting and patient-generated dietary intake tracking. The first component includes brief education on the importance of meeting energy/protein requirements in hospital; and training on how to use the hospital's electronic foodservice system, accessed via bedside computer screens. The second component involves patients recording their food intake after each meal on their bedside computer and tracking their intakes relative to their goals. This is supported with brief, daily goal-setting sessions with a health care professional. CONCLUSIONS: NUTRI-TEC is a HIT intervention designed to enable patient participation in their nutrition care in hospital. As research on HIT interventions to engage patients in health care in the hospital setting is in its infancy, and as gaps and inconsistencies in the development of such interventions exist, this paper will inform future development of HIT-based interventions in the hospital setting.

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

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.

Sports Dietitians Australia Position Statement: Nutrition for Exercise in Hot Environments.

It is the position of Sports Dietitians Australia (SDA) that exercise in hot and/or humid environments, or with significant clothing and/or equipment that prevents body heat loss (i.e., exertional heat stress), provides significant challenges to an athlete's nutritional status, health, and performance. Exertional heat stress, especially when prolonged, can perturb thermoregulatory, cardiovascular, and gastrointestinal systems. Heat acclimation or acclimatization provides beneficial adaptations and should be undertaken where possible. Athletes should aim to begin exercise euhydrated. Furthermore, preexercise hyperhydration may be desirable in some scenarios and can be achieved through acute sodium or glycerol loading protocols. The assessment of fluid balance during exercise, together with gastrointestinal tolerance to fluid intake, and the appropriateness of thirst responses provide valuable information to inform fluid replacement strategies that should be integrated with event fuel requirements. Such strategies should also consider fluid availability and opportunities to drink, to prevent significant under- or overconsumption during exercise. Postexercise beverage choices can be influenced by the required timeframe for return to euhydration and co-ingestion of meals and snacks. Ingested beverage temperature can influence core temperature, with cold/icy beverages of potential use before and during exertional heat stress, while use of menthol can alter thermal sensation. Practical challenges in supporting athletes in teams and traveling for competition require careful planning. Finally, specific athletic population groups have unique nutritional needs in the context of exertional heat stress (i.e., youth, endurance/ultra-endurance athletes, and para-sport athletes), and specific adjustments to nutrition strategies should be made for these population groups.

A qualitative exploration of factors influencing medical staffs' decision-making around nutrition prescription after colorectal surgery.

BACKGROUND: Enhanced Recovery After Surgery (ERAS) guidelines recommend early oral feeding with nutritionally adequate diets after surgery. However, studies have demonstrated variations in practice and poor adherence to these recommendations among patients who have undergone colorectal surgery. Given doctors are responsible for prescribing patients' diets after surgery, this study explored factors which influenced medical staffs' decision-making regarding postoperative nutrition prescription to identify potential behaviour change interventions. METHODS: This qualitative study involved one-on-one, semi-structured interviews with medical staff involved in prescribing nutrition for patients following colorectal surgery across two tertiary teaching hospitals. Purposive sampling was used to recruit participants with varying years of clinical experience. The Theoretical Domains Framework (TDF) underpinned the development of a semi-structured interview guide. Interviews were audio recorded, with data transcribed verbatim before being thematically analysed. Emergent themes and sub-themes were discussed by all investigators to ensure consensus of interpretation. RESULTS: Twenty-one medical staff were interviewed, including nine consultants, three fellows, four surgical trainees and five junior medical doctors. Three overarching themes emerged from the data: (i) Prescription preferences are influenced by perceptions, experience and training; (ii) Modifying prescription practices to align with patient-related factors; and (iii) Peers influence prescription behaviours and attitudes towards nutrition. CONCLUSIONS: Individual beliefs, patient-related factors and the social influence of peers (particularly seniors) appeared to strongly influence medical staffs' decision-making regarding postoperative nutrition prescription. As such, a multi-faceted approach to behaviour change is required to target individual and organisational barriers to enacting evidence-based feeding recommendations.

Nutrition for Special Populations: Young, Female, and Masters Athletes.

Adolescent, female, and masters athletes have unique nutritional requirements as a consequence of undertaking daily training and competition in addition to the specific demands of age- and gender-related physiological changes. Dietary education and recommendations for these special population athletes require a focus on eating for long-term health, with special consideration given to "at-risk" dietary patterns and nutrients (e.g., sustained restricted eating, low calcium, vitamin D and/or iron intakes relative to requirements). Recent research highlighting strategies to address age-related changes in protein metabolism and the development of tools to assist in the management of Relative Energy Deficiency in Sport are of particular relevance to special population athletes. Whenever possible, special population athletes should be encouraged to meet their nutrient needs by the consumption of whole foods rather than supplements. The recommendation of dietary supplements (particularly to young athletes) overemphasizes their ability to manipulate performance in comparison with other training/dietary strategies.

Calorie-Containing Recovery Drinks Increase Recreational Runners' Voluntary Energy and Carbohydrate Intake, with Minimal Impact on Fluid Recovery.

This study assessed voluntary dietary intake when different beverages were provided within a recovery area following recreational exercise. Participants completed two 10-km runs 1 week apart. Immediately after the first run, "beer drinkers" (n = 54; mean ± SD: age = 23.9 ± 5.8 years, body mass [BM] = 76 ± 13 kg) randomly received low-alcohol beer (Hahn Ultra® [Lion Co.], 0.9% alcohol by volume) or sports drink (SD; Gatorade® [PepsiCo]), whereas "nonbeer drinkers" (n = 78; age = 21.8 ± 2.2 years, BM = 71 ± 13 kg) received water or SD. Participants remained in a recovery area for 30-60 min with fluid consumption monitored. The following week, participants received the alternate beverage. Participants recorded all food/fluid consumed for the remainder of both trial days (diary and photographs). Fluid balance was assessed via BM change and urine specific gravity. Paired t tests were used to assess differences in hydration and dietary variables. No differences were observed in preexercise urine specific gravity (∼1.01) or BM loss (∼2%) between intervention groups (ps > .05). Water versus SD: No difference in acute fluid intake was noted (water = 751 ± 259 ml, SD = 805 ± 308 ml, p = .157). SD availability influenced total energy and carbohydrate intakes (water = 5.7 ± 2.5 MJ and 151 ± 77 g, SD = 6.5 ± 2.7 MJ and 187 ± 87 g, energy p = .002, carbohydrate p < .001). SD versus beer: SD availability resulted in greater acute fluid intake (SD = 1,047 ± 393 ml, beer = 850 ± 630 ml; p = .004), which remained evident at the end of trial days (SD = 3,337 ± 1,100 ml, beer = 2,982 ± 1,191 ml; p < .01). No differences in dietary variables were observed. Next day, urine specific gravity values were not different between water versus SD. However, a small difference was detected between SD versus beer (SD = 1.021 ± 0.009, beer = 1.016 ± 0.008, p = .002). Consuming calorie-containing drinks postexercise appears to increase daily energy and carbohydrate intake but has minimal impact on next-day hydration.

International Association of Athletics Federations Consensus Statement 2019: Nutrition for Athletics.

The International Association of Athletics Federations recognizes the importance of nutritional practices in optimizing an Athlete's well-being and performance. Although Athletics encompasses a diverse range of track-and-field events with different performance determinants, there are common goals around nutritional support for adaptation to training, optimal performance for key events, and reducing the risk of injury and illness. Periodized guidelines can be provided for the appropriate type, amount, and timing of intake of food and fluids to promote optimal health and performance across different scenarios of training and competition. Some Athletes are at risk of relative energy deficiency in sport arising from a mismatch between energy intake and exercise energy expenditure. Competition nutrition strategies may involve pre-event, within-event, and between-event eating to address requirements for carbohydrate and fluid replacement. Although a "food first" policy should underpin an Athlete's nutrition plan, there may be occasions for the judicious use of medical supplements to address nutrient deficiencies or sports foods that help the athlete to meet nutritional goals when it is impractical to eat food. Evidence-based supplements include caffeine, bicarbonate, beta-alanine, nitrate, and creatine; however, their value is specific to the characteristics of the event. Special considerations are needed for travel, challenging environments (e.g., heat and altitude); special populations (e.g., females, young and masters athletes); and restricted dietary choice (e.g., vegetarian). Ideally, each Athlete should develop a personalized, periodized, and practical nutrition plan via collaboration with their coach and accredited sports nutrition experts, to optimize their performance.

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

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 -2, 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-1 of maltodextrin (3019 ± 335 kJ). Mean 3-day EI was similar on CM and FS (7894 ± 547 vs. 7570 ± 463 kJ, p > .05), but elevated on HE (8861 ± 726 kJ, p = .012). Thus, individuals who substitute CM for a FS breakfast should be mindful that energy-dense beverages may result in increased daily EI.

Caffeine content of Nespresso® pod coffee.

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-1; p = 0.537, sleeveA = 63 ± 11, sleeveB = 59 ± 9 mg·serve-1; p = 0.134). Less caffeine was delivered in S (51 ± 7 mg·serve-1) compared to larger sizes (M = 66 ± 7 and L = 66 ± 10 mg·serve-1). 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-1, 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.

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

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 (n = 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.

Effect of 8-weeks prebiotics/probiotics supplementation on alcohol metabolism and blood biomarkers of healthy adults: a pilot study.

PURPOSE: Modulating gut bacteria via regular prebiotics/probiotics consumption may improve the metabolism of acute alcohol ingestion. This study investigated the impact of 8-weeks prebiotics/probiotics supplementation on microbiome changes and responses to acute alcohol consumption. METHODS: 38 participants (21 females, 23.6 ± 3.4 kg m-2, mean ± SD) attended the laboratory on two occasions separated by an 8-week intervention period. On each of these visits, a dose of alcohol (0.40 ± 0.04 g kg-1, Vodka + Soda-Water) was consumed over 10 min. Breath alcohol concentration was sampled over 5 h and alcohol pharmacokinetics was analysed using WinNonlin non-compartmental modelling (C max, t max, AUClast). For the intervention, participants were randomised to receive Placebo + Placebo (PLA), Placebo + Prebiotics (PRE), Probiotics + Placebo (PRO), or Probiotics + Prebiotics (SYN) in a double-blinded manner. Probiotics were a commercially available source of Lactobacillus acidophilus (NCFM®) and Bifidobacterium lactis (Bi-07). Prebiotics were a commercially available source of Larch Gum (from Larix occidentalis). Placebo was microcrystalline cellulose. Each visit, participants provided a stool sample, which was analysed to determine the presence of L. acidophilus and B. lactis. Differences between trials were analysed using paired samples t tests. RESULTS: Increased counts for at least one bacterial strain (L. acidophilus or B. lactis) were observed for all participants on SYN (n = 10) and PRO (n = 10) trials. No difference in C max or t max was observed between trials when analysed by treatment condition or microbiome outcome. A significant decrease in AUClast was observed between trials for PLA (p = 0.039) and PRE (p = 0.030) treatments, and when increases in at least one bacterial strain (p = 0.003) and no microbiome changes (p = 0.016) were observed. CONCLUSION: Consumption of probiotics appears to alter faecal counts of supplemental bacterial strains in otherwise healthy individuals. However, translation to any possible beneficial impact on alcohol metabolism remains to be elucidated.

Effects of acute exercise, dehydration and rehydration on cognitive function in well-trained athletes.

This study investigated the effects of aerobic exercise, fluid loss and rehydration on cognitive performance in well-trained athletes. Ten endurance-trained males (25 ± 5 years; 175 ± 5 cm; 70.35 ± 5.46 kg; VO2max, 62.95 ± 7.20 ml · kg.min-1) lost ~2.5 ± 0.6% body mass via continuous cycling exercise at ~65% peak sustainable power output (60 min duration) before consuming different beverages (Water = W1 and W2, Sustagen Sport = SS, Powerade = PD) and food ad libitum on four separate occasions. Cognitive function using a four-choice reaction time task (CRT), body mass, fluid consumption volumes, urine samples and subjective ratings (alertness, concentration, energy) were obtained before and after exercise, and hourly during recovery (for 4 h). CRT latency was significantly reduced immediately after exercise compared to pre-exercise measures for all trials (W1 = -16 ± 18 ms, W2 = -22 ± 21 ms, PD = -22 ± 22 ms, SS = -19 ± 26 ms). However, this effect was short-lived with subsequent measures not different from pre-exercise values. No difference in CRT accuracy was observed at any time across all trials. Subjective ratings were not different at any time across all trials. Aerobic exercise, hypohydration or an interaction between these two may provide a small cognitive performance benefit. However, these effects are temporary and confined to the immediate post-exercise period.

Tear osmolarity is sensitive to exercise-induced fluid loss but is not associated with common hydration measures in a field setting.

This investigation (i) examined changes in tear osmolarity in response to fluid loss that occurs with exercise in a field setting, and (ii) compared tear osmolarity with common field and laboratory hydration measures.  Sixty-three participants [age 27.8 ± 8.4 years, body mass 72.15 ± 10.61 kg] completed a self-paced 10 km run outside on a predetermined course. Body mass, tear fluid, venous blood and urine samples were collected immediately before and after exercise.  Significant (p < 0.001) reductions in body mass (1.71 ± 0.44%) and increases in tear osmolarity (8 ± 15 mOsm.L-1), plasma osmolality (7 ± 8 mOsm.kg-1), and urine specific gravity (0.0014 ± 0.0042 g.mL-1; p = 0.008) were observed following exercise. Pre- to post-exercise change in tear osmolarity was not significantly correlated (all p > 0.05) with plasma osmolality (rs = 0.24), urine osmolality (rs = 0.14), urine specific gravity (rs = 0.13) or relative body mass loss (r = 0.20).  Tear osmolarity is responsive to exercise-induced fluid loss but does not correlate with the changes observed using other common measures of hydration status in the field setting. Practitioners shouldn't directly compare or replace other common hydration measures with tear osmolarity in the field. ABBREVIATIONS: BML: Body Mass Loss; CV: Coefficient of Variation; Posm: Plasma osmolality; SD: Standard Deviation; Tosm: Tear Osmolarity; Uosm: Urine Osmolality; USG: Urine Specific Gravity; WBGT: Wet bulb globe thermometer.

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

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.