The effects of omega-3 polyunsaturated fatty acids on muscle and whole-body protein synthesis: a systematic review and meta-analysis.

CONTEXT: Sarcopenia describes the age-related decline in skeletal muscle mass and strength that is driven, at least in part, by an imbalance between rates of muscle protein synthesis (MPS) and muscle protein breakdown. An expanding body of literature has examined the effect of omega-3 polyunsaturated fatty acid (n-3 PUFA) ingestion on MPS rates in older adults, with mixed findings. OBJECTIVE: The aim of this systematic review and meta-analysis was to investigate the effectiveness of n-3 PUFA ingestion in stimulating rates of MPS and whole-body protein synthesis in healthy adults and clinical populations. DATA SOURCES: Searches were conducted of the PubMed, Web of Science, Cochrane Library, and Scopus databases from inception until December 2022 for articles on randomized controlled trials comparing the effect of n-3 PUFA ingestion vs a control or placebo on rates of MPS and whole-body protein synthesis. The search yielded 302 studies, of which 8 were eligible for inclusion. DATA EXTRACTION: The random effects inverse-variance model was used and standardized mean differences (SMDs) with 95%CIs were calculated to assess the pooled effect. Risk of bias was assessed by the Cochrane Risk-of-Bias 2 tool. DATA ANALYSIS: The main analysis indicated no effect of n-3 PUFA supplementation on MPS rates (k = 6; SMD: 0.03; 95%CI, -0.35 to 0.40; I2 = 30%; P = .89). Subgroup analysis based on age, n-3 PUFA dose, duration of supplementation, and method used to measure fractional synthetic rate also revealed no effect of n-3 PUFA ingestion on MPS. In contrast, the main analysis demonstrated an effect of n-3 PUFA ingestion on increasing whole-body protein synthesis rates (k = 3; SMD: 0.51; 95%CI, 0.12-0.90; I2 = 0%; P = .01). CONCLUSIONS: n-3 PUFA ingestion augments the stimulation of whole-body protein synthesis rates in healthy adults and clinical populations. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. 42022366986.

The effect of protein or amino acid provision on immobilization-induced muscle atrophy in healthy adults: A systematic review and meta-analysis.

Bed rest and limb immobilization are models of muscle disuse associated with skeletal muscle atrophy and reduced strength. The purpose of this systematic review was to examine the impact of protein or amino acid provision before and/or during a period of muscle disuse on muscle atrophy (primary outcome), strength and muscle protein synthesis (secondary outcomes) following a disuse period. We performed a systematic review of Embase, MEDLINE, Web of Science, PubMed and Clinical Trials in December 2022. Eligible studies were randomized controlled trials that combined a dietary protein or amino acid intervention versus control during an experimental model of disuse (bed rest or unilateral limb immobilization) in healthy individuals aged ≥18 years. Nine articles from eight independent trials were identified and rated for risk of bias by two authors. A meta-analysis of muscle mass data revealed no effect (standardized mean difference: 0.2; 95% confidence interval: -0.18 to 0.57, P = 0.31) of protein/amino acid intervention in preventing disuse-induced muscle atrophy. Although the meta-analysis was not conducted on strength or muscle protein synthesis data, there was insufficient evidence in the reviewed articles to support the use of protein/amino acid provision in mitigating the disuse-induced decline in either outcome measurement. Additional high-quality studies, including the reporting of randomization procedures and blinding procedures and the provision of statistical analysis plans, might be required to determine whether protein or amino acid provision serves as an effective strategy to attenuate muscle atrophy during periods of disuse.

Meeting the global protein supply requirements of a growing and ageing population.

Human dietary patterns are a major cause of environmental transformation, with agriculture occupying ~ 50% of global land space, while food production itself is responsible for ~ 30% of all greenhouse gas emissions and 70% of freshwater use. Furthermore, the global population is also growing, such that by 2050, it is estimated to exceed ~ 9 billion. While most of this expansion in population is expected to occur in developing countries, in high-income countries there are also predicted changes in demographics, with major increases in the number of older people. There is a growing consensus that older people have a greater requirement for protein. With a larger and older population, global needs for protein are set to increase. This paper summarises the conclusions from a Rank Prize funded colloquium evaluating novel strategies to meet this increasing global protein need.

Long-chain n -3 polyunsaturated fatty acids for the management of age- and disease-related declines in skeletal muscle mass, strength and physical function.

PURPOSE OF REVIEW: This review uses the hierarchy of evidence as a framework to critically evaluate the effect of long chain n -3 polyunsaturated fatty acid (LC n -3 PUFA) ingestion alone, or as an adjunctive intervention to resistance training, on muscle health-related outcomes in healthy and clinical older adult populations. RECENT FINDINGS: Systematic reviews and meta-analyses of randomized controlled trials consistently report small, but clinically-relevant, effects of LC n -3 PUFA ingestion on strength outcomes, whereas mixed findings have been reported regarding changes in muscle mass and physical function. Cohort studies indicate an association between higher dietary LC n -3 PUFA intake and reduced likelihood of a sarcopenia diagnosis. Acute metabolic studies provide limited evidence for an effect of LC n -3 PUFA ingestion alone, or in combination with resistance training, on free-living integrated rates of MPS, static markers of muscle protein breakdown, or satellite cell activation in healthy older adults. SUMMARY: Recent data supports the efficacy of LCn-3 PUFA ingestion to facilitate small, but clinically relevant, improvements in muscle strength in healthy and clinical older adult populations. The mechanism(s) that underpin the action of LC n -3 PUFA in promoting strength outcomes remain unknown, but likely relate to neuromuscular function.

Free-living competitive racewalkers and runners with energy availability estimates of <35 kcal·kg fat-free mass-1·day-1 exhibit peak serum progesterone concentrations indicative of ovulatory disturbances: a pilot study.

Introduction: The release of luteinising hormone (LH) before ovulation is disrupted during a state of low energy availability (EA). However, it remains unknown whether a threshold EA exists in athletic populations to trigger ovulatory disturbances (anovulation and luteal phase deficiency) as indicated by peak/mid-luteal serum progesterone concentration (Pk-PRG) during the menstrual cycle. Methods: We assessed EA and Pk-PRG in 15 menstrual cycles to investigate the relationship between EA and Pk-PRG in free-living, competitive (trained-elite) Guatemalan racewalkers (n = 8) and runners (n = 7) [aged: 20 (14-41) years; post-menarche: 5 (2-26) years; height: 1.53 ± 0.09 m; mass: 49 ± 6 kg (41 ± 5 kg fat-free mass "FFM")]. EA was estimated over 7 consecutive days within the follicular phase using food, training, and physical activity diaries. A fasted blood sample was collected during the Pk-PRG period, 6-8 days after the LH peak, but before the final 2 days of each cycle. Serum progesterone concentration was quantified using electrochemiluminescence immunoassay. Results: Participants that reported an EA of <35 kcal·kg FFM-1·day-1 (n = 7) exhibited ovulatory disturbances (Pk-PRG ≤9.40 ng·mL-1). Athletes with EA ≥36 kcal·kg FFM-1·day-1 (n = 8) recorded "normal"/"potentially fertile" cycles (Pk-PRG >9.40 ng·mL-1), except for a single racewalker with the lowest reported protein intake (1.1 g·kg body mass-1·day-1). EA was positively associated with Pk-PRG [r(9) = 0.79, 95% confidence interval (CI): 0.37-0.94; p = 0.003; 1 - ß = 0.99] after excluding participants (n = 4) that likely under-reported/reduced their dietary intake. Conclusions: The result from the linear regression analysis suggests that an EA ≥ 36 kcal·kg FFM-1·day-1 is required to achieve "normal ovulation." The threshold EA associated with ovulatory disturbances in athletes and non-invasive means of monitoring the ovulatory status warrant further research.

Long-chain n-3 PUFA ingestion for the stimulation of muscle protein synthesis in healthy older adults.

This review aims to critically evaluate the efficacy of long-chain Õ¸-3 PUFA ingestion in modulating muscle protein synthesis (MPS), with application to maintaining skeletal muscle mass, strength and function into later life. Ageing is associated with a gradual decline in muscle mass, specifically atrophy of type II fibres, that is exacerbated by periods of (in)voluntary muscle disuse. At the metabolic level, in otherwise healthy older adults, muscle atrophy is underpinned by anabolic resistance which describes the impaired MPS response to non-pharmacological anabolic stimuli, namely, physical activity/exercise and amino acid provision. Accumulating evidence implicates a mechanistic role for n-3 PUFA in upregulating MPS under stimulated conditions (post-prandial state or following exercise) via incorporation of EPA and DHA into the skeletal muscle phospholipid membrane. In some instances, these changes in MPS with chronic Õ¸-3 PUFA ingestion have translated into clinically relevant improvements in muscle mass, strength and function; an observation evidently more prevalent in healthy older women than men. This apparent sexual dimorphism in the adaptive response of skeletal muscle metabolism to EPA and DHA ingestion may be related to a greater propensity for females to incorporate Õ¸-3 PUFA into human tissue and/or the larger dose of ingested Õ¸-3 PUFA when expressed relative to body mass or lean body mass. Future experimental studies are warranted to characterise the optimal dosing and duration of Õ¸-3 PUFA ingestion to prescribe tailored recommendations regarding n-3 PUFA nutrition for healthy musculoskeletal ageing into later life.

Dietary protein recommendations to support healthy muscle ageing in the 21st century and beyond: considerations and future directions.

This review explores the evolution of dietary protein intake requirements and recommendations, with a focus on skeletal muscle remodelling to support healthy ageing based on presentations at the 2023 Nutrition Society summer conference. In this review, we describe the role of dietary protein for metabolic health and ageing muscle, explain the origins of protein and amino acid (AA) requirements and discuss current recommendations for dietary protein intake, which currently sits at about 0⋅8 g/kg/d. We also critique existing (e.g. nitrogen balance) and contemporary (e.g. indicator AA oxidation) methods to determine protein/AA intake requirements and suggest that existing methods may underestimate requirements, with more contemporary assessments indicating protein recommendations may need to be increased to >1⋅0 g/kg/d. One example of evolution in dietary protein guidance is the transition from protein requirements to recommendations. Hence, we discuss the refinement of protein/AA requirements for skeletal muscle maintenance with advanced age beyond simply the dose (e.g. source, type, quality, timing, pattern, nutrient co-ingestion) and explore the efficacy and sustainability of alternative protein sources beyond animal-based proteins to facilitate skeletal muscle remodelling in older age. We conclude that, whilst a growing body of research has demonstrated that animal-free protein sources can effectively stimulate and support muscle remodelling in a manner that is comparable to animal-based proteins, food systems need to sustainably provide a diversity of both plant and animal source foods, not least for their protein content but other vital nutrients. Finally, we propose some priority research directions for the field of protein nutrition and healthy ageing.

Dose-Response of Myofibrillar Protein Synthesis To Ingested Whey Protein During Energy Restriction in Overweight Postmenopausal Women: A Randomized, Controlled Trial.

BACKGROUND: Diet-induced weight loss is associated with a decline in lean body mass, as mediated by an impaired response of muscle protein synthesis (MPS). The dose-response of MPS to ingested protein, with or without resistance exercise, is well characterized during energy balance but limited data exist under conditions of energy restriction in clinical populations. OBJECTIVE: To determine the dose-response of MPS to ingested whey protein following short-term diet-induced energy restriction in overweight, postmenopausal, women at rest and postexercise. DESIGN: Forty middle-aged (58.6±0.4 y), overweight (BMI: 28.6±0.4), postmenopausal women were randomly assigned to 1 of 4 groups: Three groups underwent 5 d of energy restriction (∼800 kcal/d). On day 6, participants performed a unilateral leg resistance exercise bout before ingesting either a bolus of 15g (ERW15, n = 10), 35g (ERW35, n = 10) or 60g (ERW60, n = 10) of whey protein. The fourth group (n = 10) ingested a 35g whey protein bolus after 5 d of an energy balanced diet (EBW35, n = 10). Myofibrillar fractional synthetic rate (FSR) was calculated under basal, fed (FED) and postexercise (FED-EX) conditions by combining an L-[ring-13C6] phenylalanine tracer infusion with the collection of bilateral muscle biopsies. RESULTS: Myofibrillar FSR was greater in ERW35 (0.043±0.003%/h, P = 0.013) and ERW60 (0.042±0.003%/h, P = 0.026) than ERW15 (0.032 ± 0.003%/h), with no differences between ERW35 and ERW60 (P = 1.000). Myofibrillar FSR was greater in FED (0.044 ± 0.003%/h, P < 0.001) and FED-EX (0.048 ± 0.003%/h, P < 0.001) than BASAL (0.027 ± 0.003%/h), but no differences were detected between FED and FED-EX (P = 0.732) conditions. No differences in myofibrillar FSR were observed between EBW35 (0.042 ± 0.003%/h) and ERW35 (0.043 ± 0.003%/h, P = 0.744). CONCLUSION: A 35 g dose of whey protein, ingested with or without resistance exercise, is sufficient to stimulate a maximal acute response of MPS following short-term energy restriction in overweight, postmenopausal women, and thus may provide a per serving protein recommendation to mitigate muscle loss during a weight loss program. TRIAL REGISTRY: clinicaltrials.gov (ID: NCT03326284).

Pistachios as a recovery food following downhill running exercise in recreational team-sport individuals.

We aimed to investigate the impact of pistachio nut consumption on muscle soreness and function following exercise-induced muscle damage. Using a randomised cross-over design, male team-sport players (n = 18) performed a 40-minute downhill treadmill run to induce muscle damage, which was conducted after 2-wks of consuming either control (CON, water), a standard dose of daily pistachios (STD, 42.5 g/d) or a higher dose of daily pistachios (HIGH, 85 g/d). Lower limb muscle soreness (visual analogue scale), muscle function (maximal voluntary isokinetic torque and vertical jump), and blood markers of muscle damage/inflammation (creatine kinase, C-reactive protein, myoglobin, superoxide dismutase) were measured pre (baseline) and post (24, 48, and 72 h) exercise. No trial order effects were observed for any outcome measurement across trials. Mean quadriceps soreness (non-dominant leg) during exercise recovery was reduced (p < 0.05) in HIGH vs. CON (mean difference (95%CI): 13(1-25) mm). Change in soreness in the dominant quadriceps was not different between HIGH vs. CON (p = 0.06; mean difference (95%CI): 13(-1 to 26 mm)). No main effects of time or trial were observed for mean soreness of hamstrings, or on isokinetic torque of knee extensors or knee flexors, during recovery. Serum creatine kinase concentration peaked at 24 h post-damage (mean(SEM): 763(158)µg/L) from baseline (300(87)µg/L), but had returned to baseline by 72 h post (398(80)µg/L) exercise in all trials, with no trial or trial × time interaction evident. These data suggest that high dose pistachio nut ingestion may provide some alleviation of muscle soreness, but no effect on muscle function, following modest muscle damage.

Pistachio nuts are considered a rich source of leucine and other essential amino acids, as well as being a good source of antioxidants. These properties suggest that pistachio ingestion could potentially influence recovery from exercise induced muscle damage.Ingestion of 85 g/d of pistachios, for 2-wks prior to and during recovery from exercise-induced muscle damage, significantly reduced muscle soreness in the non-dominant limb knee extensors, in comparison to 0 g/d control.No effects of pistachio ingestion were observed on muscle function or blood markers of damage suggesting that a mechanism of action on soreness is likely related to blunting of the inflammation response. However, further work is required to explore these effects in a larger sample when greater damage is induced.

The effect of combined ß-lactoglobulin supplementation and resistance exercise training prior to limb immobilisation on muscle protein synthesis rates in healthy young adults: study protocol for a randomised controlled trial.

BACKGROUND: The decline in skeletal muscle mass experienced following a short-term period (days to weeks) of muscle disuse is mediated by impaired rates of muscle protein synthesis (MPS). Previous RCTs of exercise or nutrition prehabilitation interventions designed to mitigate disuse-induced muscle atrophy have reported limited efficacy. Hence, the aim of this study is to investigate the impact of a complex prehabilitation intervention that combines ß-lactoglobulin (a novel milk protein with a high leucine content) supplementation with resistance exercise training on disuse-induced changes in free-living integrated rates of MPS in healthy, young adults. METHODS/DESIGN: To address this aim, we will recruit 24 healthy young (18-45 years) males and females to conduct a parallel, double-blind, 2-arm, randomised placebo-controlled trial. The intervention group will combine a 7-day structured resistance exercise training programme with thrice daily dietary supplementation with 23 g of ß-lactoglobulin. The placebo group will combine the same training programme with an energy-matched carbohydrate (dextrose) control. The study protocol will last 16 days for each participant. Day 1 will be a familiarisation session and days 2-4 will be the baseline period. Days 5-11 represent the 'prehabilitation period' whereby participants will combine resistance training with their assigned dietary supplementation regimen. Days 12-16 represent the muscle disuse-induced 'immobilisation period' whereby participants will have a single leg immobilised in a brace and continue their assigned dietary supplementation regimen only (i.e. no resistance training). The primary endpoint of this study is the measurement of free-living integrated rates of MPS using deuterium oxide tracer methodology. Measurements of MPS will be calculated at baseline, over the 7-day prehabilitation period and over the 5-day immobilisation period separately. Secondary endpoints include measurements of muscle mass and strength that will be collected on days 4 (baseline), 11 (end of prehabilitation) and 16 (end of immobilisation). DISCUSSION: This novel study will establish the impact of a bimodal prehabilitation strategy that combines ß-lactoglobulin supplementation and resistance exercise training in modulating MPS following a short-term period of muscle disuse. If successful, this complex intervention may be translated to clinical practice with application to patients scheduled to undergo, for example, hip or knee replacement surgery. TRIAL REGISTRATION: NCT05496452. Registered on August 10, 2022. PROTOCOL VERSION: 16-12-2022/1.

Co-Ingestion of Branched-Chain Amino Acids and Carbohydrate Stimulates Myofibrillar Protein Synthesis Following Resistance Exercise in Trained Young Men.

Branched-chain amino acids (BCAA) and carbohydrate (CHO) are commonly recommended postexercise supplements. However, no study has examined the interaction of CHO and BCAA ingestion on myofibrillar protein synthesis (MyoPS) rates following exercise. We aimed to determine the response of MyoPS to the co-ingestion of BCAA and CHO following an acute bout of resistance exercise. Ten resistance-trained young men completed two trials in counterbalanced order, ingesting isocaloric drinks containing either 30.6-g CHO plus 5.6-g BCAA (B + C) or 34.7-g CHO alone following a bout of unilateral, leg resistance exercise. MyoPS was measured postexercise with a primed, constant infusion of L-[ring13C6] phenylalanine and collection of muscle biopsies pre- and 4 hr postdrink ingestion. Blood samples were collected at time points before and after drink ingestion. Serum insulin concentrations increased to a similar extent in both trials (p > .05), peaking at 30 min postdrink ingestion. Plasma leucine (514 ± 34 nmol/L), isoleucine (282 ± 23 nmol/L), and valine (687 ± 33 nmol/L) concentrations peaked at 0.5 hr postdrink in B + C and remained elevated for 3 hr during exercise recovery. MyoPS was ∼15% greater (95% confidence interval [-0.002, 0.028], p = .039, Cohen's d = 0.63) in B + C (0.128%/hr ± 0.011%/hr) than CHO alone (0.115%/hr ± 0.011%/hr) over the 4 hr postexercise period. Co-ingestion of BCAA and CHO augments the acute response of MyoPS to resistance exercise in trained young males.

Fish oil supplementation fails to modulate indices of muscle damage and muscle repair during acute recovery from eccentric exercise in trained young males.

We aimed to investigate the influence of 4-wk of fish oil (FO) supplementation on markers of muscle damage, inflammation, muscle soreness, and muscle function during acute recovery from eccentric exercise in moderately trained males. Sixteen moderately-trained males ingested 5 g/d of FO (n = 8) or soybean oil (placebo) capsules (n = 8) for 4-wk prior to- and 3-d following an acute eccentric exercise bout. Eccentric exercise consisted of 12 sets of isokinetic knee extension and knee flexion. Indices of muscle damage, soreness, function and inflammation were measured at baseline and during exercise recovery. Eccentric exercise elicited an increase in muscle soreness (p < 0.010) and thigh volume (p < 0.001), and reduced peak isometric torque by 31.7 ± 6.9%, (p < 0.05, 95% CI 10.6-52.8) during 3-d of recovery. Blood omega-3 polyunsaturated fatty acid concentration was 14.9 ± 2.4% higher in FO than PLA (p < 0.01, 95% CI 9.8-20.1). However, FO did not ameliorate the cumulative creatine kinase response (expressed as AUC; p = 0.368), inflammation (p = 0.400), muscle soreness (p > 0.140), or muscle function (p > 0.249) following eccentric exercise. FO supplementation confers no clear benefit in terms of ameliorating the degree of muscle damage, or facilitating the muscle repair process, during acute eccentric exercise recovery. These data suggest that FO supplementation does not provide an effective nutritional strategy to promote exercise recovery, at least in moderately-trained young men.Abbreviations: ANOVA: Analysis of variance; AUC: Area under curve; CI: Confidence interval; CK: Creatine kinase; CMJ: Countermovement jump; COX: Cyclooxygenase; CRP: C-reactive protein; DHA: Docosahexaenoic acid; DOMS: Delayed-onset muscle soreness; EIMD: Exercise-induced muscle damage; En%: Energy percent; EPA: Eicosapentaenoic acid; FO: Fish oil; IL-6: Interleukin-6; LDH: Lactate dehydrogenase; LOX: Lipoxygenase; Mb: Myoglobin; mTOR: Mechanistic target of rapamycin; PLA: Placebo; ROM: Range of motion; ROS: Reactive oxygen species; SD: Standard deviation; SEM: Standard error of the mean; TNF-α: Tumour necrosis factor alpha; VAS: Visual analogue scale; Ω3-PUFA: Omega-3 polyunsaturated fatty acids; Ω6-PUFA: Omega-6 polyunsaturated fatty acidsHighlightsThe anti-inflammatory properties of omega-3 polyunsaturated fatty acids, alongside their propensity to incorporate into the muscle phospholipid membrane underpins the idea that fish oil supplementation may attenuate muscle damage and promote muscle repair following eccentric-based exercise.Four weeks of high-dose (5 g/d) fish oil supplementation prior to eccentric exercise failed to attenuate the rise in creatine kinase concentration and muscle soreness during acute exercise recovery in physically-active young men.Future studies are warranted to investigate the efficacy of combining omega-3 polyunsaturated fatty acids with other nutrients (i.e. protein/amino acids) for the promotion of muscle recovery following eccentric-based damaging exercise.

Shorter sleep duration is associated with greater visceral fat mass in US adults: Findings from NHANES, 2011-2014.

Habitual declines in sleep duration and increased rates of obesity are public health concerns worldwide. Accumulating evidence suggests a prominent link between reduced sleep duration and weight gain. Our cross-sectional study investigated the relationship between sleep duration and body fat distribution in US adults. We extracted data for 5151 participants (2575 men and 2576 women) aged 18-59 years from the US National Health and Nutrition Examination Survey 2011-2012 and 2013-2014. Weekday or workday night-time sleep duration was estimated using an in-home interview questionnaire. Dual-energy x-ray absorptiometry scans were used to determine regional body fat mass (arms, legs, trunk [android and gynoid], and abdominal [subcutaneous and visceral]). Multiple linear regression and restricted cubic spline analyses were performed after adjusting for several demographic, anthropometric, and nutritional covariates. There was a significant negative association between sleep duration and visceral fat mass overall (ß: -12.139, P < 0.001) and by sex (men: ß: -10.096, P < 0.001; women: ß: -11.545, P = 0.038), after adjusting for age, ethnicity, body mass index, total body fat mass, daily energy and alcohol intake, sleep quality and sleep disorder status. Sleep duration and visceral fat appeared to plateau at ≥ 8 h of daily sleep. Sleep duration is negatively associated with visceral fat mass accumulation during adulthood with possibly no benefits beyond 8 h of sleep per day. Mechanistic and prospective studies are required to confirm the effect of sleep duration on visceral adiposity and determine its causes.

Impact of probiotics on muscle mass, muscle strength and lean mass: a systematic review and meta-analysis of randomized controlled trials.

Probiotics have shown potential to counteract sarcopenia, although the extent to which they can influence domains of sarcopenia such as muscle mass and strength in humans is unclear. The aim of this systematic review and meta-analysis was to explore the impact of probiotic supplementation on muscle mass, total lean mass and muscle strength in human adults. A literature search of randomized controlled trials (RCTs) was conducted through PubMed, Scopus, Web of Science and Cochrane Library from inception until June 2022. Eligible RCTs compared the effect of probiotic supplementation versus placebo on muscle and total lean mass and global muscle strength (composite score of all muscle strength outcomes) in adults (>18 years). To evaluate the differences between groups, a meta-analysis was conducted using the random effects inverse-variance model by utilizing standardized mean differences. Twenty-four studies were included in the systematic review and meta-analysis exploring the effects of probiotics on muscle mass, total lean mass and global muscle strength. Our main analysis (k = 10) revealed that muscle mass was improved following probiotics compared with placebo (SMD: 0.42, 95% CI: 0.10-0.74, I2  = 57%, P = 0.009), although no changes were revealed in relation to total lean mass (k = 12; SMD: -0.03, 95% CI: -0.19 - 0.13, I2  = 0%, P = 0.69). Interestingly, a significant increase in global muscle strength was also observed among six RCTs (SMD: 0.69, 95% CI: 0.33-1.06, I2  = 64%, P = 0.0002). Probiotic supplementation enhances both muscle mass and global muscle strength; however, no beneficial effects were observed in total lean mass. Investigating the physiological mechanisms underpinning different ageing groups and elucidating appropriate probiotic strains for optimal gains in muscle mass and strength are warranted.

Handgrip strength is associated with learning and verbal fluency in older men without dementia: insights from the NHANES.

Low handgrip strength, a hallmark measure of whole-body strength, has been linked with greater odds of cognitive decline and dementia; however, conflicting findings, which could be due to population characteristics and choice of tools, such for the assessment of handgrip strength and cognitive function domains, also exist. Therefore, we examined the relationship of handgrip strength with a comprehensive list of tests to assess domains of cognitive function using a representative sample of US older men and women without neurodegenerative disorders such as dementia. We analyzed cross-sectional data from the US National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014, with a study cohort of 777 older adults (380 men and 397 women) above 60 years of age. Handgrip strength was assessed using a handgrip dynamometer, while cognitive function was assessed through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test (WLLT), Word List Recall Test (WLRT), Intrusion Word Count Test (WLLT-IC and WLRT-IC), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). Sex-stratified multiple linear regression analyses were performed upon covariate adjustment for age, ethnicity, socio-economic status, education, medical history, body mass index, physical activity, energy, protein, and alcohol intake. Maximal handgrip strength was positively associated with cognitive function scores, including CERAD WLLT (P = 0.009, R2 = 0.146) and AFT (P = 0.022, R2 = 0.024) in older men, but not in women (CERAD WLLT: P = 0.253, AFT: P = 0.370). No significant associations with CERAD WLLRT (men: P = 0.057, women: P = 0.976), WLLT-IC (men: P = 0.671, women: P = 0.869), WLLRT-IC (men: P = 0.111, women: P = 0.861), and DSST (men: P = 0.108, women: P = 0.091) were observed. Dose-response curves exhibited a prominent linear relationship between all significant associations after covariate adjustment, with no indication of a plateau in these relationships. In conclusion, higher handgrip strength was independently associated with better learning ability for novel verbal information and verbal fluency in US men over the age of 60 and without dementia. Longitudinal studies are required to confirm whether muscle strength independently predicts cognitive function changes in older adults in a sex-specific manner, and whether this connection is affirmed to the possibility of reverse causation due to declines in physical activity levels in the preclinical phase of dementia.

Chronic almond nut snacking alleviates perceived muscle soreness following downhill running but does not improve indices of cardiometabolic health in mildly overweight, middle-aged, adults.

Introduction: As a popular food snack rich in protein, fiber, unsaturated fatty acids, antioxidants and phytonutrients, almond nut consumption is widely associated with improvements in cardiometabolic health. However, limited data exists regarding the role of almond consumption in improving exercise recovery. Accordingly, we aimed to investigate the impact of chronic almond snacking on muscle damage and cardiometabolic health outcomes during acute eccentric exercise recovery in mildly overweight, middle-aged, adults. Methods: Using a randomized cross-over design, 25 mildly overweight (BMI: 25.8 ± 3.6 kg/m2), middle-aged (35.1 ± 4.7 y) males (n = 11) and females (n = 14) performed a 30-min downhill treadmill run after 8-weeks of consuming either 57 g/day of whole almonds (ALMOND) or an isocaloric amount (86 g/day) of unsalted pretzels (CONTROL). Muscle soreness (visual analogue scale), muscle function (vertical jump and maximal isokinetic torque) and blood markers of muscle damage (creatine kinase (CK) concentration) and inflammation (c-reactive protein concentration) were measured pre and post (24, 48, and 72 h) exercise. Blood biomarkers of cardiometabolic health (total cholesterol, triglycerides, HDL cholesterol, and LDL cholesterol), body composition and psycho-social assessments of mood (POMS-2 inventory), appetite and well-being were measured pre and post intervention. Results: Downhill running successfully elicited muscle damage, as evidenced by a significant increase in plasma CK concentration, increased perception of muscle soreness, and impaired vertical jump performance (all p < 0.05) during acute recovery. No effect of trial order was observed for any outcome measurement. However, expressed as AUC over the cumulative 72 h recovery period, muscle soreness measured during a physical task (vertical jump) was reduced by ~24% in ALMOND vs. CONTROL (p < 0.05) and translated to an improved maintenance of vertical jump performance (p < 0.05). However, ALMOND did not ameliorate the CK response to exercise or isokinetic torque during leg extension and leg flexion (p > 0.05). No pre-post intervention changes in assessments of cardiometabolic health, body composition, mood state or appetite were observed in ALMOND or CONTROL (all p > 0.05). Conclusion: Chronic almond supplementation alleviates task-specific perceived feelings of muscle soreness during acute recovery from muscle damaging exercise, resulting in the better maintenance of muscle functional capacity. These data suggest that almonds represent a functional food snack to improve exercise tolerance in mildly overweight, middle-aged adults.

Influence of pistachios on force production, subjective ratings of pain, and oxidative stress following exercise-induced muscle damage in moderately trained athletes: A randomized, crossover trial.

Although previous studies have focused on the role of pistachios on metabolic health, the ergogenic effects of the nut must be elucidated. This study evaluated the impact of ingesting raw, shelled, unsalted pistachios on subjective pain ratings, force production, vertical jump, and biochemical indices of recovery from eccentrically biased exercise. Using a crossover design, 27 moderately trained, male athletes completed 3 trials in a randomized counterbalanced fashion. Control received water only, low dose (1.5 oz/d; PL) and high dose (3.0 oz/d; PH) consumed pistachios for 2 weeks with a 3-4-week washout between trials. PH had lower pain ratings in most muscles after 72 h of recovery (p < 0.05). PH prevented a decrease in force production at 120°/s of knee flexion (p > 0.05); whereas force was diminished in the other trials. Creatine kinase, myoglobin, and C-reactive protein increased over time following exercise (p < 0.05); however, there were no advantages following pistachio consumption. No significant changes in vertical jump or superoxide dismutase were elicited during any trial. This study demonstrates that 3.0 oz/d of pistachios can reduce delayed onset of muscle soreness and maintain muscle strength, potentially promoting exercise tolerance and training adaptations. ClinicalTrialsgov Identifier: NCT03698032.

Effects of short-term pistachio consumption before and throughout recovery from an intense exercise bout on cardiometabolic markers.

Although pistachios have been shown to improve cardiometabolic biomarkers in diseased and at-risk populations, less research has been conducted on young, healthy individuals. Furthermore, some but not all research indicates that exercise acutely improves cardiometabolic markers; however, it remains unclear as to why outcomes vary among studies. This research evaluated secondary aims of a study designed to assess the impacts of pistachios on recovery from vigorous eccentrically-biased exercise. Here we examined the short-term (two weeks) effects of two different doses (1.5 oz/d and 3.0 oz/d) of pistachios and a water-only control on the biomarkers of metabolic health in young adult men. This was followed by daily blood collection for three consecutive days after a 40-min downhill run. Twenty-seven participants completed each of three conditions in a counterbalanced randomized order. Plasma biomarkers (lipid profile, glucose, and insulin) were measured at the end of each 2-week feeding period immediately before the exercise bout and again 24, 48, and 72 h thereafter. Two weeks of pistachio consumption failed to elicit changes in any biomarker (p < .05).. Exercise reduced LDL-cholesterol at the end of the recovery period; however, positive effects were limited to when subjects were consuming the higher dose of pistachios. Follow up t-tests revealed significant reductions in LDL-C in the high dose group at 72-H compared to that at 0-H (8.2 ± 19.4; p < .04), 24-H (8.0 ± 18.6; p < .04), and 48-H (9.3 ± 15.8; p < .005) post exercise within the same trial. Overall, in healthy young men with normal blood lipid and glucose metabolism, little effect of either pistachios or intense exercise on cardiometabolic risk indicators was detected. More research is needed to determine the influence of usual diet consumption on outcomes following an acute exercise bout.

Aberrant mitochondrial homeostasis at the crossroad of musculoskeletal ageing and non-small cell lung cancer.

Cancer cachexia is accompanied by muscle atrophy, sharing multiple common catabolic pathways with sarcopenia, including mitochondrial dysfunction. This study investigated gene expression from skeletal muscle tissues of older healthy adults, who are at risk of age-related sarcopenia, to identify potential gene biomarkers whose dysregulated expression and protein interference were involved in non-small cell lung cancer (NSCLC). Screening of the literature resulted in 14 microarray datasets (GSE25941, GSE28392, GSE28422, GSE47881, GSE47969, GSE59880 in musculoskeletal ageing; GSE118370, GSE33532, GSE19804, GSE18842, GSE27262, GSE19188, GSE31210, GSE40791 in NSCLC). Differentially expressed genes (DEGs) were used to construct protein-protein interaction networks and retrieve clustering gene modules. Overlapping module DEGs were ranked based on 11 topological algorithms and were correlated with prognosis, tissue expression, and tumour purity in NSCLC. The analysis revealed that the dysregulated expression of the mammalian mitochondrial ribosomal proteins, Mitochondrial Ribosomal Protein S26 (MRPS26), Mitochondrial Ribosomal Protein S17 (MRPS17), Mitochondrial Ribosomal Protein L18 (MRPL18) and Mitochondrial Ribosomal Protein L51 (MRPL51) were linked to reduced survival and tumour purity in NSCLC while tissue expression of the same genes followed an opposite direction in healthy older adults. These results support a potential link between the mitochondrial ribosomal microenvironment in ageing muscle and NSCLC. Further studies comparing changes in sarcopenia and NSCLC associated cachexia are warranted.