Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme最新文献

Poor glucose regulation associated with gradual insulin resistance is a significant risk factor in several age-related chronic diseases. An eating plan that promotes a lower carbohydrate intake may have a beneficial effect on glucose metabolism. This study aimed to evaluate how a diet reduced in carbohydrate by 32% (RCHO) over a 2 month period would influence the metabolic profile of older individuals (N = 24) living in a retirement home (RH). A continuous glucose monitor was used to measure blood glucose during four periods: the standard diet before (baseline) and after (washout) the intervention, during the 4 initial days of the RCHO diet (RCHO-early), and the final days of the 2 month intervention (RCHO-end). The blood metabolic profile was also measured (glucose, ketones, insulin, triglycerides, and cholesterol). RCHO intake decreased average blood glucose compared to the standard diet in hyperglycemic participants: RCHO-early 7.8 ± 1.0 vs 7.5 ± 1.1 mM (p = 0.012) and RCHO-end 7.8 ± 1.0 vs 7.0 ± 0.9 mM (p = 0.050). In the hyperglycemic participants, the percentage of time spent in hyperglycemia (>10.0 mM) decreased by 50% during the RCHO-early (p = 0.012) and by 66% at RCHO-end (p  = 0.021) compared to baseline. Glycated hemoglobin was significantly lower at RCHO-end in both hyperglycemic and normoglycemic participants compared to baseline (p < 0.008). Plasma ketones increased threefold in hyperglycemic participants at RCHO-end compared to baseline (p < 0.028). This study shows that an RCHO diet has metabolic health benefits in an older population and confirms its safety, tolerability, and acceptability in an RH (NCT06022094).

High consumption of ultra-processed foods and drinks (UPF) has been linked to poor diet quality and an increased risk of non-communicable diseases. To inform public policies and interventions aimed at reducing UPF intake in Canada, updated information on UPF intake among different sociodemographic groups is needed. This study, using data from 5872 adults aged 18 years and older from the International Food Policy Study (2018-2019), aims to estimate the dietary energy contribution of UPF and assess its variation among sociodemographic subgroups. All foods and drinks reported in a single 24 h dietary recall were classified using the Nova system. We estimated the mean proportion of total daily energy from UPF and subcategories of UPF in the overall sample and among sociodemographic subgroups. Multivariable linear regression models evaluated the association between sociodemographic characteristics with the proportion of total daily energy from UPF. On average, adults consumed 45.2% of their total daily energy from UPF. UPF consumption was slightly higher among males than females (49.4% vs. 47.6%, p = 0.039) and younger adults aged 19-30 years compared with older adults aged 51-64 years (50.0% vs. 47.2%, p = 0.029), adjusting for a range of sociodemographic factors. Overall, UPF consumption was relatively high among adults in all sociodemographic subgroups, highlighting the need for policies to decrease UPF consumption in the entire population.

This randomized, placebo-controlled, double-blind, parallel trial investigated whether generally healthy adult, nonelite runners would have a greater time-to-exhaustion during submaximal treadmill running with probiotic versus placebo supplementation. It was hypothesized that the probiotic would impact training progression by reducing gastrointestinal (GI) and cold/flu symptoms. Participants who typically ran ≥24 km/week, ran or cross-trained 3-5 days per week, and had a maximal oxygen intake (V̇O₂ max) in the 60-85th percentile were enrolled. V̇O₂ max was used to establish individualized workload settings (85% of V̇O₂ max) for the submaximal endurance tests at baseline and following 6 weeks of supplementation with a probiotic (Lactobacillus helveticus Lafti L10, 5×10⁹ CFU/capsule/day) or placebo. Participants self-reported GI and cold/flu symptoms and physical activity via daily and weekly questionnaires. Outcomes were tested using a linear model to determine if mean response values adjusted for baseline differed between groups. Twenty-eight participants (n = 14/group), aged 25 ± 5 years (mean ± SD) with a body mass index of 23 ± 3 kg/m², completed the study. At the final visit the probiotic group had a lower time-to-exhaustion versus the placebo group (P = 0.01) due to an increase in time-to-exhaustion with the placebo (1344 ± 188 to 1565 ± 219 s, P = 0.01) with no change with the probiotic (1655 ± 230 to 1547 ± 215 s, P = 0.23). During the intervention, the probiotic group completed fewer aerobic training sessions per week (P = 0.02) and trained at a lower intensity (P = 0.007) versus the placebo group. Few GI and cold/flu symptoms were reported with no differences between groups. Time-to-exhaustion increased in the placebo group, possibly due to differences in training habits.

We recently explored the cardiopulmonary interactions during partial unloading of the respiratory muscles during exercise. Expanding upon this work, we present a noteworthy case study whereby we eliminated the influence of respiration on cardiac function in a conscious but mechanically ventilated human during exercise. This human was a young healthy endurance-trained male who was mechanically ventilated during semi-recumbent cycle exercise at 75 Watts (W) (∼30% W_max). During mechanically ventilated exercise, esophageal pressure was reduced to levels indistinguishable from the cardiac artefact which led to a 94% reduction in the power of breathing. The reduction in respiratory pressures and respiratory muscle work led to a decrease in cardiac output (-6%), which was due to a reduction in stroke volume (-13%), left ventricular end-diastolic volume (-15%), and left-ventricular end-systolic volume (-17%) that was not compensated for by heart rate. Our case highlights the influence of extreme mechanical ventilation on cardiac function while noting the possible presence of a maximal physiological limit to which respiration (and its associated pressures) impacts cardiac function when the power of breathing is maximally reduced.

Disordered eating refers to a range of eating behaviours and attitudes towards weight and food that can negatively influence physical and psychosocial well-being. The menopausal transition could be a vulnerable period for disordered eating due to major hormonal fluctuations, menopausal symptoms, common body composition shifts, and an increased risk of psychological challenges. This systematic review aimed to summarize evidence on the associations between the menopausal transition and disordered eating. Records published before October 2023 were identified through MEDLINE, PsycINFO, Scopus, Embase, and CINAHL. Studies investigating associations between menopausal status, menopausal symptoms, or reproductive hormone levels, and disordered eating during the menopausal transition were sought. A total of 1301 non-duplicate records were screened, with 10 studies deemed eligible for inclusion. Most included studies used a cross-sectional design (n = 9). Findings include potentially higher levels of binge eating during the perimenopausal stage, whereas restrictive eating behaviours appeared more common during postmenopause compared to premenopause. Both studies investigating menopausal symptoms found strong positive associations with disordered eating. Nonetheless, findings are equivocal with contrasting results and limited methodological quality across studies. Further research is needed to verify these findings and better assist health professionals in supporting healthy eating behaviours in menopausal women during this complex transition. (PROSPERO ID: CRD42021290736).

Snacking is nearly universal among children but there is growing concern around snacking patterns and energy contribution. This study aimed to characterize temporal snacking patterns among Canadian children and adolescents. A cross-sectional analysis drew on data from 5209 respondents aged 4-18 years from the 2015 Canadian Community Health Survey Nutrition, using one 24 h dietary recall. Descriptive statistics estimated proportions of morning, afternoon, and evening snackers, the mean caloric contribution of each snacking period to total daily energy intake, and the top food categories consumed as snacks (kcal per capita). Snacking was nearly universal and accounted for one of every four calories consumed. Morning snacks were more popular among children vs. adolescents and contributed significantly less energy than afternoon or evening snacking periods for both age groups (P < 0.001). The top food groups consumed as snacks were the same for children and adolescents, although the ranking order varied. Fruits were the leading food group in terms of per capita energy for children and second for adolescents. Aside from fruits and milks, all other top per capita energy contributors were generally more energy-dense, nutrient-poor foods such as cookies, biscuits and cereal bars, and other breads. Among children, morning snacks were higher in desirable nutrients compared with afternoon snacks. Not all snacking periods are equal in terms of energy and nutrients. A better understanding of how time of day may influence the quality of snack foods can inform meal-based guidance and help children achieve the recommended daily amounts of foods and nutrients.

This paper provides an overview of topics discussed by clinicians and researchers invited to speak at the Canadian Nutrition Society's Thematic Conference 2023, which was centered on advances in research and practice in the assessment and treatment of disordered eating and eating disorders. Presenters emphasized the importance of understanding how systemic factors such as racism, weight stigma, and COVID-19 affect the assessment and treatment of eating disorders, and proposed strategies for addressing these inequities. In this paper, we provide actionable recommendations for clinicians working with individuals with eating disorders; professional development, cultural competence, and equitable assessment and treatment practices are discussed.

This study investigated the impact of a multiday heatwave on nocturnal physiology, behavior, and sleep under controlled conditions with comprehensive monitoring of environmental factors and participant activities. Seven young healthy males were confined for 10 days in controlled conditions that ranged between hot-to-warm (day: 35.4 °C, night: 26.3 °C) during nights 4-6 and temperate (day: 25.4 °C, night: 22.3 °C) before (nights 1-3) and after (nights 7-10) the heatwave. Measurements included core and skin temperatures, heart rate, sympathovagal balance, vasomotion indicators, urine samples, blanket coverage, subjective sleep assessments, and partial polysomnography. The average nocturnal core temperature was 0.2 °C higher during and after the heatwave compared to the pre-heatwave period, with this difference being more pronounced (+0.3 °C) in the first 2 h of sleep (p < 0.001). For every 0.1 °C rise in overnight core temperature, the total sleep time decreased by 14 min (pseudo-R² = 0.26, p = 0.01). The elevated core temperatures occurred despite the participants exhibiting evident thermoregulatory behavior, as they covered 30% less body surface during the heatwave compared to pre- and post-heatwave periods (p < 0.001). During the heatwave, mean skin temperature at bedtime was 1.3 °C higher than pre-heatwave and 0.8 °C higher than post-heatwave periods (p < 0.001). No differences in other responses, including heart rate and vasomotion indicators, were observed. The paper details a 20-min sleepwalking episode that was coupled with marked changes in sleepwalker's thermophysiological responses. In conclusion, the simulated heatwave resulted in higher overnight core temperature which was associated with reduced total sleep time. Behavioral thermoregulation during sleep may serve as a defense against these effects, though more research is needed.

We investigated the influence of anaerobic speed reserve (ASR) on post-activation performance enhancement (PAPE). Twenty-two endurance runners and triathletes were evaluated for maximum sprinting speed (MSS) and countermovement jump (CMJ) before (non-fatigued) and after (fatigued) an incremental running test. They were allocated in LASR (low-ASR) and HASR (high-ASR) groups for comparisons between conditions. HASR showed greater CMJ and MSS (both p ≤ 0.005) performances, with enhanced CMJ in fatigued condition (p ≤ 0.008). Significant correlations were found between ASR, CMJ, and MSS in both conditions (p ≤ 0.01) for the entire sample, and between ∆CMJ and ∆MSS (p ≤ 0.001) in LASR. Our results show that ASR profile influences PAPE.

Reference equations for fat-free mass (FFM) and lean soft tissue mass (LM) measures obtained from dual-energy X-ray absorptiometry (DEXA) are important for the interpretation of body composition. This study developed and validated reference equations for FFM and LM using DEXA from the Canadian Longitudinal Study on Aging. Reference equations were developed using data from a random population-based sample of ostensibly healthy and functionally independent adults aged 45-85 years. Reference equations for absolute (accounting for age, sex, height, and body mass) and height-adjusted aka index (accounting for age, sex, and body mass index) measures of FFM and LM were developed using quantile regression. Reference equations were respectively developed and validated in derivation (80%) and validation cohorts (20%). Reference equations were applied to symptomatic adults with self-reported chronic obstructive pulmonary disease (COPD) or heart disease to assess discriminant validity; and compared with other published equations to assess performance. Bland-Altman analyses and Lin's concordance correlation coefficients were utilised to assess agreement. Reference equations for 5th, 10th, 50th, 90th, and 95th percentiles were developed for DEXA-derived estimates of FFM and LM based on 1881 healthy participants (57% male) aged 55 [IQR: 50-61] years. Reference equations performed comparably in the validation cohort and discriminated reference values between ostensibly healthy adults and people with symptomatic COPD or heart disease. Previously published reference equations tended to over- or under-predict estimates of LM compared with the current reference equations. This study provides a comprehensive and validated set of reference equations for estimating and interpreting FFM and LM from DEXA in Canadian adults aged 45-85 years, although additional validation may be required for those >75 years.