Evaluation of self-contained breathing apparatus (SCBA) weight on firefighter stamina, comfort, and postural stability.

Firefighters wear personal protective equipment to protect them from the thermal and chemical environment in which they operate. The self-contained breathing apparatus (SCBA) provides isolation of the airway from the hazardous fireground. National standards limit SCBA weight, however, integration of additional features could result in an SCBA exceeding the current limit. The purpose of this study was to examine the effects of increased SCBA weight on firefighters' physiological responses, work output, dynamic stability, and comfort. Completion of simulated firefighting activities induced a strong physiological response. Peak oxygen consumption was higher with the lightest SCBA than the heaviest SCBA. Few other physiological differences were noted as SCBA weight increased. Importantly, increased SCBA weight resulted in significantly more negative perceptions by the firefighters and a trend towards significance for the duration of work time prior to reaching volitional fatigue. These results should be considered when assessing changes to existing SCBA weight limits.

Increased SCBA weight above existing national standards resulted in negative perceptions by the firefighters, but not significant physiological changes after two simulated bouts of firefighting activity. SCBA weight had a nearly significant impact on the time firefighters worked before reaching volitional fatigue, with heavier SCBA trending towards decreased working time.

Dietary patterns and carotenoid intake: Comparisons of MIND, Mediterranean, DASH, and Healthy Eating Index.

The Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND) dietary pattern is associated with reduced cognitive decline and dementia risk. However, the nutrient features that distinguish the MIND from other patterns are unknown. We investigated the relationship between accordance to the MIND pattern and carotenoid intake (phytonutrients hypothesized to confer neuroprotection) relative to the Mediterranean, DASH, and Healthy Eating Index (HEI-2020). We hypothesized that MIND diet accordance would be a stronger predictor of carotenoid intake relative to other diet indices. A total of 396 adults (aged 19-82 years) completed the Dietary History Questionnaire to assess carotenoid intake and adherence to each diet index. Stepwise regressions with adjustment for covariates followed by the Meng's Z-test were used to compare correlation strength between each diet pattern and carotenoid. All diet patterns were positively associated with lutein and zeaxanthin, ß-carotene, α-carotene, and ß-cryptoxanthin (all ßs ≥0.38, Ps <.01). Effect size comparisons revealed that MIND accordance predicted a greater proportion of variance in lutein and zeaxanthin (all Zs ≥ 3.3, Ps < .001) and ß-carotene (all Zs ≥ 2.6, Ps < .01) relative to the Mediterranean, DASH, and HEI-2020. MIND accordance explained a greater proportion of variance in α-carotene (Z = 3.8, P < .001) and ß-cryptoxanthin (Z = 3.6, P < .001) relative to the HEI-2020. MIND diet accordance was disproportionately related to carotenoid intake, indicating the MIND index places greater emphasis on carotenoid-rich foods, particularly those containing lutein, zeaxanthin, and ß-carotene, relative to other diet indices. Future research is needed to define the role of these carotenoids in nutritional interventions for cognitive health.

Acute Microbial Protease Supplementation Increases Net Postprandial Plasma Amino Acid Concentrations After Pea Protein Ingestion in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled Trial.

BACKGROUND: Digestibility is a primary factor in determining the quality of dietary protein. Microbial protease supplementation may be a strategy for improving protein digestion and subsequent postprandial plasma amino acid availability. OBJECTIVES: To assess the effect of co-ingesting a microbial protease mixture with pea protein on postprandial plasma amino acid concentrations. DESIGN: A mixture of 3 microbial protease preparations (P3) was tested for proteolytic efficacy in an in vitro static simulation of gastrointestinal digestion. Subsequently, in a randomized, double-blind, placebo-controlled crossover trial, 24 healthy adults (27 ± 4 y; 12 females, 12 males) ingested 25 g pea protein isolate (20 g protein, 2.2 g fat) with either P3 or maltodextrin placebo (PLA). Blood samples were collected at baseline and throughout a 0‒5 h postprandial period and both the early (0-2 h) iAUC and total (0-5 h) iAUC were examined. RESULTS: Plasma glucose concentrations decreased in both conditions (P < 0.001), with higher concentrations after P3 ingestion compared with PLA (P < 0.001). Plasma insulin concentrations increased for both conditions (P < 0.001) with no difference between conditions (P = 0.331). Plasma total amino acid (TAA) concentrations increased over time (P < 0.001) with higher concentrations observed for P3 compared with PLA (P = 0.010) during the 0‒5 h period. There was a trend for elevated essential amino acid (EAA) concentrations for P3 compared with PLA (P = 0.099) during the 0‒5 h postprandial period but not for leucine (P = 0.282) or branched-chain amino acids (BCAA, P = 0.410). The early net exposure (0‒2 h iAUC) to amino acids (leucine, BCAA, EAA, and TAA) was higher for P3 compared with PLA (all, P < 0.05). CONCLUSIONS: Microbial protease co-ingestion increases plasma TAA concentrations (0-5 h) and leucine, BCAA, EAA, and TAA availability in the early postprandial period (0‒2 h) compared with ingesting pea protein with placebo in healthy adults.

Postabsorptive and postprandial myofibrillar protein synthesis rates at rest and after resistance exercise in women with postmenopause.

Feeding and resistance exercise stimulate myofibrillar protein synthesis (MPS) rates in healthy adults. This anabolic characterization of "healthy adults" has been namely focused on males. Therefore, the purpose of this study was to examine the temporal responses of MPS and anabolic signaling to resistance exercise alone or combined with the ingestion of protein in postmenopausal females and compare postabsorptive rates with young females. Sixteen females [60 ± 7 yr; body mass index (BMI) = 26 ± 12 kg·m-2] completed an acute bout of unilateral resistance exercise before consuming either: a fortified whey protein supplement (WHEY) or water. Participants received primed continuous infusions of L-[ring-13C6]phenylalanine with bilateral muscle biopsies before and after treatment ingestion at 2 h and 4 h in nonexercised and exercised legs. Resistance exercise transiently increased MPS above baseline at 0-2 h in the water condition (P = 0.007). Feeding after resistance exercise resulted in a late phase (2-4 h) increase in MPS in the WHEY condition (P = 0.005). In both conditions, resistance exercise did not enhance the cumulative (0-4 h) MPS response. In the nonexercised leg, MPS did not differ at 0-2 h, 2-4 h, or 0-4 h of the measurement periods (all, P > 0.05). Likewise, there were no changes in the phosphorylation of p70S6K, AMPKα, or total and phosphorylated yes-associated protein on Ser127. Finally, postabsorptive MPS was lower in premenopausal versus postmenopausal females (P = 0.023). Our results demonstrate that resistance exercise-induced changes in MPS are temporally regulated, but do not result in greater cumulative (0-4 h) MPS in postmenopausal women.NEW & NOTEWORTHY An adequate quality and quantity of skeletal muscle is relevant to support physical performance and metabolic health. Muscle protein synthesis (MPS) is an established remodeling marker, which can be hypertrophic or nonhypertrophic. Importantly, protein ingestion and resistance exercise are two strategies that support healthy muscle by stimulating MPS. Our study shows postmenopause modulates baseline MPS that may diminish the MPS response to the fundamental anabolic stimuli of protein ingestion and resistance exercise in older females.

International Society of Sports Nutrition Position Stand: Effects of essential amino acid supplementation on exercise and performance.

Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of literature surrounding the effects of essential amino acid (EAA) supplementation on skeletal muscle maintenance and performance. This position stand is intended to provide a scientific foundation to athletes, dietitians, trainers, and other practitioners as to the benefits of supplemental EAA in both healthy and resistant (aging/clinical) populations. EAAs are crucial components of protein intake in humans, as the body cannot synthesize them. The daily recommended intake (DRI) for protein was established to prevent deficiencies due to inadequate EAA consumption. The following conclusions represent the official position of the Society: 1. Initial studies on EAAs' effects on skeletal muscle highlight their primary role in stimulating muscle protein synthesis (MPS) and turnover. Protein turnover is critical for replacing degraded or damaged muscle proteins, laying the metabolic foundation for enhanced functional performance. Consequently, research has shifted to examine the effects of EAA supplementation - with and without the benefits of exercise - on skeletal muscle maintenance and performance. 2. Supplementation with free-form EAAs leads to a quick rise in peripheral EAA concentrations, which in turn stimulates MPS. 3. The safe upper limit of EAA intake (amount), without inborn metabolic disease, can easily accommodate additional supplementation. 4. At rest, stimulation of MPS occurs at relatively small dosages (1.5-3.0 g) and seems to plateau at around 15-18 g. 5. The MPS stimulation by EAAs does not require non-essential amino acids. 6. Free-form EAA ingestion stimulates MPS more than an equivalent amount of intact protein. 7. Repeated EAA-induced MPS stimulation throughout the day does not diminish the anabolic effect of meal intake. 8. Although direct comparisons of various formulas have yet to be investigated, aging requires a greater proportion of leucine to overcome the reduced muscle sensitivity known as "anabolic resistance." 9. Without exercise, EAA supplementation can enhance functional outcomes in anabolic-resistant populations. 10. EAA requirements rise in the face of caloric deficits. During caloric deficit, it's essential to meet whole-body EAA requirements to preserve anabolic sensitivity in skeletal muscle.

Postabsorptive muscle protein synthesis is higher in outpatients as compared to inpatients.

Several factors affect muscle protein synthesis (MPS) in the postabsorptive state. Extreme physical inactivity (e.g., bedrest) may reduce basal MPS, whereas walking may augment basal MPS. We hypothesized that outpatients would have a higher postabsorptive MPS than inpatients. To test this hypothesis, we conducted a retrospective analysis. We compared 152 outpatient participants who arrived at the research site the morning of the MPS assessment with 350 Inpatient participants who had an overnight stay in the hospital unit before the MPS assessment the following morning. We used stable isotopic methods and collected vastus lateralis biopsies ∼2 to 3 h apart to assess mixed MPS. MPS was ∼12% higher (P < 0.05) for outpatients than inpatients. Within a subset of participants, we discovered that after instruction to limit activity, outpatients (n = 13) took 800 to 900 steps in the morning to arrive at the unit, seven times more steps than inpatients (n = 12). We concluded that an overnight stay in the hospital as an inpatient is characterized by reduced morning activity and causes a slight but significant reduction in MPS compared with participants studied as outpatients. Researchers should be aware of physical activity status when designing and interpreting MPS results.NEW & NOTEWORTHY The postabsorptive muscle protein synthesis rate is lower in the morning after an overnight inpatient hospital stay compared with an outpatient visit. Although only a minimal amount of steps was conducted by outpatients (∼900), this was enough to increase postabsorptive muscle protein synthesis rate.

MIND dietary pattern adherence is inversely associated with visceral adiposity and features of metabolic syndrome.

The effects of following the Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay (MIND) diet on metabolic health remains understudied. This cross-sectional analysis of 163 adults investigated associations between adherence to the MIND, Mediterranean, DASH, and Healthy Eating Index (HEI-2015) diets and metabolic syndrome (MetS) features and visceral adiposity. We hypothesized that the MIND diet would show the most beneficial associations with MetS risk factors. Diet adherence was assessed using the Dietary History Questionnaire II. Visceral adipose was assessed using dual-energy X-ray absorptiometry. Waist circumference and systolic and diastolic blood pressures were obtained. Fasting blood triglycerides, high-density lipoprotein cholesterol, and glucose concentrations were determined. Stepwise regression analyses were applied. Waist circumference was inversely associated with DASH (ß = -0.21, P < .01), HEI-2015 (ß = -0.18, P = .01), and MIND (ß = -0.19, P < .01). Triglycerides were inversely associated with DASH (ß = -0.19, P = .01), HEI-2015 (ß = -0.18, P = .02), and MIND (ß = -0.23, P < .01). High-density lipoprotein cholesterol was positively associated with Mediterranean (ß = 0.18, P = .02) and MIND (ß = 0.21, P < .01). Systolic blood pressure was inversely associated with Mediterranean (ß = -0.18, P = .02), DASH (ß = -0.30, P < .01), HEI-2015 (ß = -0.24, P < .01), and MIND (ß = -0.25, P < .01). Diastolic blood pressure was inversely associated with Mediterranean (ß = -0.26, P < .01), DASH (ß = -0.34, P < .01), HEI-2015 (ß = -0.24, P < .01), and MIND (ß = -0.31, P < .01). Fasting glucose was inversely associated with MIND (ß = -0.19, P = .02). Visceral adiposity was inversely associated with Mediterranean (ß = -0.19, P < .01), DASH (ß = -0.22, P < .01), HEI-2015 (ß = -0.22, P < .01), and MIND (ß = -0.28, P < .01). Although each diet exhibited potential benefits for metabolic outcomes, only greater MIND diet adherence was associated with lower visceral adiposity and each MetS feature in adults.

Underpinning the Food Matrix Regulation of Postexercise Myofibrillar Protein Synthesis by Comparing Salmon Ingestion With the Sum of Its Isolated Nutrients in Healthy Young Adults.

BACKGROUND: Protein is most commonly consumed as whole foods as opposed to single nutrients. However, the food matrix regulation of the postprandial muscle protein synthetic response has received little attention. OBJECTIVES: The purpose of this study was to assess the effects of eating salmon (SAL) and of ingesting the same nutrients as an isolated mixture of crystalline amino acids and fish oil (ISO) on the stimulation of postexercise myofibrillar protein synthesis (MPS) and whole-body leucine oxidation rates in healthy young adults. METHODS: Ten recreationally active adults (24 ± 4 y; 5 men, 5 women) performed an acute bout of resistance exercise, followed by the ingestion of SAL or ISO in a crossover fashion. Blood, breath, and muscle biopsies were collected at rest and after exercise during primed continuous infusions of L-[ring-2H5]phenylalanine and L-[1-13C]leucine. All data are presented as means ± SD and/or mean differences (95% CIs). RESULTS: Postprandial essential amino acid (EAA) concentrations peaked earlier (P = 0.024) in the ISO group than those in the SAL group. Postprandial leucine oxidation rates increased over time (P < 0.001) and peaked earlier in the ISO group (1.239 ± 0.321 nmol/kg/min; 63 ± 25 min) than those in the SAL group (1.230 ± 0.561 nmol/kg/min; 105 ± 20 min; P = 0.003). MPS rates for SAL (0.056 ± 0.022 %/h; P = 0.001) and ISO (0.046 ± 0.025 %/h; P = 0.025) were greater than the basal rates (0.020 ± 0.011 %/h) during the 0- to 5-h recovery period, with no differences between conditions (P = 0.308). CONCLUSION: We showed that the postexercise ingestion of SAL or ISO stimulate postexercise MPS rates with no differences between the conditions. Thus, our results indicate that ingesting protein from SAL as a whole-food matrix is similarly anabolic to ISO in healthy young adults. This trial was registered at www. CLINICALTRIALS: gov as NCT03870165.

Protein quality and the food matrix: defining optimal versus maximal meal-based protein intakes for stimulating muscle protein synthesis.

This paper examines the opinion that we should aim to optimize, rather than maximize, protein intakes to avoid over-emphasizing muscle-centric protein requirements. An optimal eating approach strives to minimize amino acid oxidative waste and more efficiently stimulate postprandial muscle protein accretion. To do this, practitioners should acknowledge higher quality protein foods as better in delivering target amounts of amino acids into circulation, and the food matrix (e.g., nutrient-nutrient interactions) can be leveraged to potentiate essential amino acid incorporation into skeletal muscle protein.

Dietary fiber intake and fecal short-chain fatty acid concentrations are associated with lower plasma lipopolysaccharide-binding protein and inflammation.

Consuming adequate dietary fiber is a promising strategy for reducing systemic inflammation. The objective was to evaluate relationships between dietary fiber intake, markers of metabolic endotoxemia, and systemic inflammation in adults. This was a cross-sectional study of 129 healthy participants (age 33.6 ± 6.1 yr, BMI 30.5 ± 6.9 kg/m2). Dietary fiber intake was assessed by food frequency questionnaire. Adiposity was measured using dual-energy X-ray absorptiometry (DXA). Fecal short-chain fatty acids (SCFA) were quantified using gas chromatography-mass spectrometry. Fecal microbiota sequence data (V4 region, 16S rRNA gene) were analyzed using DADA2 and QIIME2. Inflammatory cytokines were assessed with enzyme-linked immunosorbent assays; flow cytometry was conducted for monocyte surface marker quantification. Bivariate correlations and generalized step-wise linear modeling were used for statistical analyses. Plasma C-reactive protein (CRP) and interleukin (IL)-6 concentrations were positively related to whole body (CRP r = 0.45, P = <0.0001; IL-6 r = 0.34, P = 0.0002) and visceral adiposity (CRP r = 0.33, P = 0.0003; IL-6 r = 0.38, P = 0.0002). Plasma lipopolysaccharide-binding protein (LBP) concentrations were inversely related to dietary fiber intake (r = -0.22, P = 0.03) and fecal SCFA (acetate r = -0.25, P = 0.01; propionate r = -0.28, P = 0.003; butyrate r = -0.23, P = 0.02). Whole body adiposity, dietary fiber, and fecal SCFA were the most predictive of plasma LBS-BP concentrations. Novel findings included associations between dietary fiber intake, the gastrointestinal microbiota, and systemic inflammation.NEW & NOTEWORTHY Dietary fiber intake may reduce the inflammation associated with obesity and metabolic disease. Our cross-sectional analysis revealed that dietary fiber intake and fecal short-chain fatty acids are inversely associated with lipopolysaccharide-binding protein, a marker of systemic inflammation. In addition, plasma interleukin-6 and C-reactive protein were positively related to markers of adiposity.

Associations between Accelerometer-Measured Physical Activity and Fecal Microbiota in Adults with Overweight and Obesity.

PURPOSE: We aimed to assess whether total daily physical activity (PA), PA intensities, sedentary time (ST), and prolonged ST are associated with differences in the gut microbiota composition or short-chain fatty acid (SCFA) profile of adults with overweight or obesity. METHODS: Cross-sectional associations between total daily PA (counts per minute), PA intensities (light and moderate-to-vigorous (MVPA)), ST, prolonged ST, and fecal microbiota composition were assessed in adults ( n = 124) between 25 and 45 yr of age with body mass index ≥25 kg·m -2 . Fecal microbiota composition was assessed with 16S rRNA gene sequencing. Daily PA and ST were measured with a hip-worn ActiGraph wGT3X-BT accelerometer. RESULTS: Daily PA volume and intensity were positively associated with relative abundance of Faecalibacterium ( P = 0.04) and negatively associated with the abundances of Alistipes , Parabacteroides , and Gemmiger ( P = 0.003-0.04) as well as the concentrations of acetate, butyrate, and total SCFA (all P = 0.04). Conversely, ST was negatively associated with abundance of Faecalibacterium but positively associated with the abundances of taxa, including Ruminococcaceae, Parabacteroides , Alistipes , and Gemmiger . Clustering of participants based on whether they met PA recommendations suggested that SCFA profiles differed between individuals who did and did not meet PA recommendations. K-means clustering based on percent of time spent in MVPA and ST also identified differences in fecal microbiota composition between cluster 1 (lower MVPA, higher ST) and cluster 2 (higher MVPA, lower ST), including a higher abundance of Alistipes in cluster 1. CONCLUSIONS: The current analysis suggests a beneficial association of daily PA on the fecal microbiota and a negative association of ST, particularly with respect to the associations of these variables with the genera Faecalibacterium , a butyrate-producing taxon.

Advanced Glycation End Products and Inflammatory Cytokine Profiles in Maintenance Hemodialysis Patients After the Ingestion of a Protein-Dense Meal.

OBJECTIVE: The goal of this investigation was to evaluate circulating and skeletal muscle inflammatory biomarkers between maintenance hemodialysis (MHD) and demographic-matched control subjects (CON) before and after ingestion of a protein-rich meal. DESIGN AND METHODS: CON (n = 8; 50 ± 2 years; 31 ± 1 kg/m2) and MHD patients (n = 8; 56 ± 5 years; 32 ± 2 kg/m2) underwent a basal blood draw and muscle biopsy and serial blood draws after the ingestion of a mixed meal on a nondialysis day. Plasma advanced glycation end products (AGEs) and markers of oxidation were assessed via liquid chromatography-tandem mass spectrometry before and after the meal (+240 min). Circulating inflammatory cytokines and soluble receptors for AGE (sRAGE) isoforms (endogenous secretory RAGEs and cleaved RAGEs) were determined before and after the meal (+240 min). Basal muscle was probed for inflammatory cytokines and protein expression of related signaling components (RAGE, Toll-like receptor 4, oligosaccharyltransferase subunit 48, TIR-domain-containing adapter-inducing interferon-ß, total IκBα, and pIκBα). RESULTS: Basal circulating AGEs were 7- to 343-fold higher (P < .001) in MHD than those in CON, but only MG-H1 increased in CON after the meal (P < .001). There was a group effect (MHD > CON) for total sRAGEs (P = .02) and endogenous secretory RAGEs (P < .001) and a trend for cleaved RAGEs (P=.09), with no meal effect. In addition, there was a group effect (MHD < CON; P < .05) for circulating fractalkine, interleukin (IL)10, IL17A, and IL1ß and a trend (P < .10) for IL6 and macrophage inflammatory protein 1 alpha, whereas tumor necrosis factor alpha was higher in MHD (P < .001). In muscle, Toll-like receptor 4 (P = .03), TIR-domain-containing adapter-inducing interferon-ß (P = .002), and oligosaccharyltransferase subunit 48 (P = .02) expression was lower in MHD than that in CON, whereas IL6 was higher (P = .01) and IL8 (P = .08) tended to be higher in MHD. CONCLUSION: Overall, MHD exhibited an exaggerated, circulating, and skeletal muscle inflammatory biomarker environment, and the meal did not appreciably affect the inflammatory status.

Sex-based comparisons of muscle cellular adaptations after 10 weeks of progressive resistance training in middle-aged adults.

Resistance training combined with adequate protein intake supports skeletal muscle strength and hypertrophy. These adaptations are supported by the action of muscle stem cells (MuSCs), which are regulated, in part, by fibro-adipogenic progenitors (FAPs) and circulating factors delivered through capillaries. It is unclear if middle-aged males and females have similar adaptations to resistance training at the cellular level. To address this gap, 27 (13 males, 14 females) middle-aged (40-64 yr) adults participated in 10 wk of whole body resistance training with dietary counseling. Muscle biopsies were collected from the vastus lateralis pre- and posttraining. Type II fiber cross-sectional area increased similarly with training in both sexes (P = 0.014). MuSC content was not altered with training; however, training increased PDGFRα+/CD90+ FAP content (P < 0.0001) and reduced PDGFRα+/CD90- FAP content (P = 0.044), independent of sex. The number of CD31+ capillaries per fiber also increased similarly in both sexes (P < 0.05). These results suggest that muscle fiber hypertrophy, stem/progenitor cell, and capillary adaptations are similar between middle-aged males and females in response to whole body resistance training.NEW & NOTEWORTHY We demonstrate that resistance training-induced increases in fiber hypertrophy, FAP content, and capillarization are similar between middle-aged males and females.

Leucine ingestion promotes mTOR translocation to the periphery and enhances total and peripheral RPS6 phosphorylation in human skeletal muscle.

The activation of the mechanistic target of rapamycin complex 1 (mTORC1), a master regulator of protein synthesis, by anabolic stimuli (such as muscle contraction or essential amino acids) involves its translocation to the cell periphery. Leucine is generally considered the most anabolic of amino acids for its ability to independently modulate muscle protein synthesis. However, it is currently unknown if free leucine impacts region-specific mTORC1-mediated phosphorylation events and protein-protein interactions. In this clinical trial (NCT03952884; registered May 16, 2019), we used immunofluorescence methods to investigate the role of dietary leucine on the postprandial regulation of mTORC1 and ribosomal protein S6 (RPS6), an important downstream readout of mTORC1 activity. Eight young, healthy, recreationally active males (n = 8; 23 ± 3 yrs) ingested 2 g of leucine with vastus lateralis biopsies collected at baseline, 30, 60, and 180 min postprandial. Leucine promoted mTOR translocation to the periphery (~ 18-29%; p ≤ 0.012) and enhanced mTOR localization with the lysosome (~ 16%; both p = 0.049) at 30 and 60 min post-feeding. p-RPS6Ser240/244 staining intensity, a readout of mTORC1 activity, was significantly elevated at all postprandial timepoints in both the total fiber (~ 14-30%; p ≤ 0.032) and peripheral regions (~ 16-33%; p ≤ 0.014). Additionally, total and peripheral p-RPS6Ser240/244 staining intensity at 60 min was positively correlated (r = 0.74, p = 0.036; r = 0.80, p = 0.016, respectively) with rates of myofibrillar protein synthesis over 180 min. The ability of leucine to activate mTORC1 in peripheral regions favors an enhanced rate of MPS, as this is the intracellular space thought to be replete with the cellular machinery that facilitates this anabolic process.

MIND Dietary Pattern Adherence Is Selectively Associated with Cognitive Processing Speed in Middle-Aged Adults.

BACKGROUND: Most previous work has focused on a single-nutrient, bottom-up approach when examining the influence of diet on neurocognition. Thus, the impact of dietary patterns on cognitive health is underinvestigated. OBJECTIVES: We aimed to investigate the relation between different diet indices [i.e., Mediterranean, Dietary Approaches to Stop Hypertension (DASH), Healthy Eating Index-2015 (HEI-2015), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND)] and attentional inhibition and neuroelectric function. METHODS: We undertook a cross-sectional analysis of adults aged 34.1 ± 6.0 y (n = 207, 116 females) with a BMI of 18.5 to >40 kg/m2 who completed the Dietary History Questionnaire II (DHQII) FFQ (Past Month and Year with Serving Sizes) to assess adherence to different diet quality indices. Attentional inhibition was assessed using a modified Eriksen flanker task during which event-related potentials (ERPs) were recorded. The amplitude and latency of the P3/P300 ERP were used to index attentional resource allocation and information processing speed, respectively. RESULTS: P3 peak latency was inversely associated with greater adherence to the MIND dietary pattern during incongruent flanker trials (∆R2 = 0.02, ß = -0.14, P = 0.043) but not during congruent trials. Adherence to the Mediterranean, DASH, and HEI-2015 patterns was not associated with P3 latency (P > 0.05). No associations were observed between the diet indices and attentional inhibition at the behavioral level (i.e., accuracy or reaction time) or P3 amplitude (all P values >0.05). CONCLUSIONS: Greater adherence to the MIND diet was selectively associated with faster information processing speed in middle-aged adults with healthy to obese BMI. Further, the influence of the MIND diet for faster information processing speed might be particularly beneficial when cognitive control demands are increased. Future intervention trials testing the effects of consuming a MIND diet on cognitive function are warranted to help inform dietary recommendations for healthy cognitive aging.

Neuroelectric indices of motor response preparation are selectively associated with physical activity among adults with obesity.

Previous work has demonstrated that physical activity and weight status are associated with attentional inhibition (indexed with the P3 component of event-related potentials). However, there is limited knowledge on the neural underpinnings of motor response planning and activation. This study investigated the effect of weight status on relationships between moderate-to-vigorous physical activity (MVPA) and the lateralized readiness potential (LRP), a neuroelectric index of motor response planning and activation. Adults (N = 165 [98 females]) wore ActiGraph wGT3X+ accelerometers to measure physical activity. Behavioral outcomes were recorded during the modified Eriksen Flanker task to assess attentional inhibition. EEG recordings were taken to elucidate response- (LRP-R) and stimulus-locked (LRP-S) LRPs, and P3. Participants were separated into groups based on the BMI cutoff of 30 kg/m2 (i.e., non-obese [n = 88], obese [n = 77]). Independent t-tests and ANCOVA were conducted to determine differences between groups. Regression analyses within each group were conducted to determine relationships between MVPA and LRP and P3 amplitude and latencies. There was no difference in MVPA between weight groups after adjustment for age and sex, although the non-obese group had significantly higher incongruent accuracy (p = 0.007). Only in the obese group, MVPA was positively associated with LRP-R incongruent (ß = 0.014, p = 0.029) and LRP-S congruent (ß = 0.013, p = 0.008) amplitude, and inversely associated with LRP-S incongruent (ß = -0.488, p = 0.017) and P3 congruent (ß = 0.013, p = 0.008) fractional area latency. MVPA was associated with pre-motor planning and activation only among persons with obesity. Future work should study the impact of physical activity on neuroelectric indices of motor responses in people with obesity.

Cathepsin B and Muscular Strength are Independently Associated with Cognitive Control.

Although muscular strength has been linked to greater cognitive function across different cognitive domains, the mechanism(s) through which this occurs remain(s) poorly understood. Indeed, while an emerging body of literature suggests peripheral myokines released from muscular contractions may play a role in this relationship, additional research is needed to understand this link. Accordingly, this study sought to compare the influences of a particular myokine, Cathepsin B (CTSB), and muscular strength on hippocampal-dependent relational memory and cognitive control in 40 adults (age = 50.0±7.3 yrs). Overnight fasted venous blood draws were taken to assess plasma CTSB and muscular strength was assessed as maximal isokinetic strength testing using a Biodex dynamometer. Cognitive performance was assessed using a Spatial Reconstruction Task to assess relational memory and a modified Flanker task to assess cognitive control. Neuroelectric function for cognitive control was assessed using event-related potentials (ERPs) recorded during the Flanker task. Initial bivariate correlational analyses revealed that neither sex, age, lean body mass, or muscular strength was associated with CTSB. However, CTSB was inversely associated with reaction time and fractional peak latency of the P3 component of the Flanker task. Muscular strength was also inversely associated with reaction time and positively associated with relational memory performance. However, the influence of muscular strength on relational memory did not persist following adjustment for covariates. Greater circulating CTSB was selectively associated with greater cognitive control as well as faster information processing speed. These findings are the first to link circulating CTSB to both cognitive control and neuroelectric function. Future intervention studies are needed to examine the effects of changes in muscular strength, circulating myokines, and different domains of cognitive function.