Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults

Healthy ageing in older adults with cardiovascular disease

As life expectancy continues to increase due to advancements in medical technology, public health, nutrition, and socioeconomic progress, the population of older adults in the USA and Europe is rapidly growing. By 2050, individuals aged 65 and older are projected to constitute over 20% of the US population and 29% of the European population, leading to a higher prevalence of chronic diseases, including cardiovascular disease. Cardiovascular disease, the leading cause of death in the USA, poses significant challenges to healthy ageing by contributing to accelerated biological ageing and the development of geriatric syndromes. This state-of-the-art review aims to (i) define healthy ageing for older patients living with cardiovascular disease; (ii) compare chronological vs biological ageing as it pertains to cardiovascular disease; (iii) describe the impact of geriatric syndromes and provide an approach to management and prevention; and (iv) address the gaps in knowledge and future directions for potential interventions that could promote healthy ageing.

Investigating muscle protein synthesis using deuterium oxide: The impact of dietary protein interventions across the lifespan

This review highlights recent advancements in our understanding of muscle protein synthesis (MPS) across the lifespan, with a focus on dietary protein strategies to support muscle health. Given that skeletal muscle is crucial for whole-body metabolism, movement and independence, maintaining muscle mass throughout life is essential. However, the gradual decline in muscle mass and strength with age, known as sarcopenia, represents a significant health concern. Muscle mass is regulated by the balance of MPS and muscle protein breakdown, with dietary protein intake playing a central role in stimulating MPS and maintaining a positive protein balance. Much of our current understanding of protein intake, specifically its quantity, quality and distribution, comes from stable isotope-labelled amino acid methods. These techniques, however, are limited by time constraints and controlled settings, providing only brief snapshots of MPS dynamics. The use of deuterium oxide (D₂O) has provided new insights, enabling long-term measures of muscle protein metabolism in free-living conditions. Measurements of longer-term MPS using D₂O suggest that older adults might benefit from protein intakes of >1.2 g/kg/day to enhance MPS. Additionally, replacing protein in the diet with higher-quality sources or enriching lower protein intakes with leucine can further increase MPS. Nevertheless, discrepancies remain regarding optimal protein requirements and the long-term efficacy of supplementing with enriched suboptimal protein doses. The continued application of D₂O in dietary protein research has the potential to provide further insights into the prolonged effects of various protein strategies on muscle preservation across the lifespan.

Skeletal Muscle Atrophy Induced by Dexamethasone Is Attenuated by Amino Acid Complex Supplementation in Rats

Muscle atrophy, a physiological decline in muscle mass and strength due in ageing, occurs through an imbalance between protein breakdown and synthesis. The purpose of this study was to verify whether amino acid complex supplementation (ACS) can prevent and treat muscle loss in a dexamethasone (Dexa, 800 μg/kg)-induced rat model of sarcopenia. Sprague Dawley rats (6 weeks old) were assigned to seven groups: (i) normal control, (ii) positive control (high-dose ACS, 500 mg), (iii) Dexa only, (iv) Dexa + high-dose ACS (500 mg), (v) Dexa + medium-dose ACS (300 mg), (vi) Dexa + low-dose ACS (100 mg), or (vii) Dexa + liquid amino acid complex formulation (LF, 2 mL), administered orally for 4 weeks. Exercise capacity tests were performed five times using a treadmill test (TT) and forced swimming test (FST). The body weight increase in each group was less than that of the normal group. The blood biochemical indices, AST levels, and AST/ALT ratio significantly increased in the Dexa-treated medium-dose ACS group. The total muscle protein also significantly increased in all ACS groups. In the Dexa-treated LF group, CK decreased below the normal level. Exercise capacity, assessed by TT and FST, increased the most in the positive control and Dexa-treated high-dose ACS groups. In the TT, the Dexa-only group increased by about 18%, but the Dexa-treated high-dose ACS group increased by about 110%. Additionally, in the FST, Dexa-treated rats receiving a high dose of ACS demonstrated significantly increased exercise time and capacity. Electron microscopic (EM) and hematoxylin and eosin (H&E) observations of muscle tissue revealed muscle fiber atrophy in the gastrocnemius muscles of the Dexa-only group. In the EM findings of the Dexa-treated high-dose ACS group, the M-line and Z-line were clearer than in the Dexa-only group, and the mitochondria were partially preserved. In conclusion, the ACS-treated rats showed a clear recovery from muscle damage based on serum indices, total muscle protein mass, and the microscopic findings on muscle tissue. Notably, a high dose of ACS demonstrated the most effective protection and recovery of muscle tissue in the Dexa-induced sarcopenia rat model.

Plasma Metabolite Profiles Between In-Center Daytime Extended-Hours and Conventional Hemodialysis

Key Points

Significant differences in 39 plasma metabolites were observed between patients on extended-hours hemodialysis and those on conventional hemodialysis. Extended-hours hemodialysis had a lower lactate-to-pyruvate ratio and higher branched-chain amino acids than conventional hemodialysis. Extended-hours hemodialysis may have favorable metabolic and nutritional benefits for patients undergoing maintenance hemodialysis.

Background

Protein–energy wasting, characterized by disordered body protein catabolism resulting from metabolic and nutritional derangements, is associated with adverse clinical outcomes in patients undergoing hemodialysis. Extended-hours hemodialysis (≥6 hours per treatment session) offers both enhanced removal of uremic solutes and better fluid management, generally allowing more liberalized dietary protein and calorie intake. The aim of this study was to evaluate the difference in plasma metabolite profiles among patients receiving in-center daytime extended-hours hemodialysis and those receiving conventional hemodialysis.

Methods

Predialysis plasma samples were obtained from 188 patients on extended-hours hemodialysis (21.9 h/wk) and 286 patients on conventional hemodialysis (12.1 h/wk) in Japan in 2020 using capillary electrophoresis-mass spectrometry. Group differences were compared for 117 metabolites using Wilcoxon rank-sum tests with multiple comparisons and partial least squares discriminant analysis. In addition, propensity score–adjusted multiple regression analyses were performed to evaluate group differences for known uremic toxins, branched-chain amino acids, and lactate-to-pyruvate ratio (a possible surrogate marker of mitochondrial dysfunction).

Results

Significant differences were observed in 39 metabolites, largely consistent with the high variable importance for prediction in partial least squares discriminant analysis. Among known uremic toxins, uridine and hypoxanthine levels were significantly higher in the conventional hemodialysis group than in the extended-hours hemodialysis group, whereas trimethylamine N -oxide levels were higher in the extended-hours hemodialysis group than in the conventional hemodialysis group. Patients on extended-hours hemodialysis had higher levels of all branched-chain amino acids and a lower lactate-to-pyruvate ratio than those on conventional hemodialysis (significant difference of −8.6 [95% confidence interval, −9.8 to −7.4]).

Conclusions

Extended-hours hemodialysis was associated with a more favorable plasma metabolic and amino acid profile; however, concentrations of most uremic toxins did not significantly differ from those of conventional hemodialysis.

Comparative response of casein protein hydrolysate-fed young and older human serum on in vitro muscle protein metabolism and myotube size

In this study, we used an ex vivo-in vitro model to assess the effect of feeding older (50-70 yr) adults a casein protein hydrolysate (CPH) compared with nonbioactive nonessential amino acid (NEAA) supplement on muscle protein synthesis (MPS) and markers of muscle protein breakdown (MPB). As a secondary objective, to assess any attenuation with aging, we compared the anabolic response to CPH-fed serum from older and young adults. Serum from seven healthy older and seven young men following overnight fast and 60-min postprandial ingestion of CPH or NEAA (0.33 g·kg-1 body mass) was used to condition C2C12 myotube media. Analysis by two-way ANOVA of the fed relative to fasted MPS response revealed a main effect for protein type in pmTOR (P = 0.009), p70S6K (P = 0.031), p4E-BP1 (P = 0.047), and MPS (P = 0.041) with a greater response to CPH-fed serum, and interaction effects (age × protein) between young and old serum for pmTOR (P = 0.009) and p70S6K (P = 0.016). In addition, significant changes in myotube diameter (P = 0.049), atrogin-1 (P = 0.004), and MuRF-1 (P = 0.012) in response to CPH-fed compared with fasted serum were observed with no differences between young and old serum. In conclusion, this study demonstrated that CPH-fed serum from both young and older (50-70 yr) adults can stimulate MPS and muscle growth and can suppress biomarkers of muscle protein breakdown processes.NEW & NOTEWORTHY This study extended previously developed coculture models and found that treating skeletal muscle cells with ex vivo human serum following feeding with a casein protein hydrolysate resulted in greater protein signaling, muscle protein synthesis, muscle growth, and lower expression of genes related to muscle protein breakdown compared with feeding with a nonessential amino acid control. These findings were similar using serum from young and older adults.

Influence of exercise and dietary habits on the association of alpha-actinin-3 gene polymorphisms with physical function and body composition in community-dwelling individuals aged 60 years and older

AIM

Alpha-actinin 3 (ACTN3) is associated with diminished physical function and muscle mass in older individuals. However, the effects of lifestyle on this relationship remain unclear. This study explored whether the association between ACTN3 polymorphisms and physical function and body composition varied based on exercise and dietary habits.

METHODS

A longitudinal analysis of 197 community-dwelling individuals aged 60 years and older (mean age 72.5 ± 5.9 years, 60.9% women) in the Tarumizu study provided data on ACTN3 gene polymorphisms, with surveys completed in 2019 and 2022 (mean follow-up 1156 ± 80.0 days). Physical performance (grip strength, walking speed) and body composition (body weight, appendicular skeletal muscle mass [ASMM], and fat mass) were assessed. Genetic polymorphisms were analyzed in oral mucosa samples and categorized into type R allele carriers and type XX alleles (homozygous for minor alleles). Median values determined exercise habits (≤4 days/week or ≥5 days/week) and dietary habits based on high-protein-food frequency scores.

RESULTS

The proportion of type XX genetic polymorphism was 26.4%. Two-way repeated-measures analysis of covariance showed a significant interaction between genetic polymorphism and time for ASMM (F = 10.552, P = 0.002) in the ≤4 days/week exercise habits group. Significant interactions were observed in grip strength (F = 7.013, P = 0.009) and ASMM (F = 5.347, P = 0.023) for the ≤11 score high-protein-intake group.

CONCLUSIONS

This association may contribute to accelerated age-related changes in physical performance and body composition, particularly among individuals with type XX genetic polymorphism who have low exercise habits and a limited intake of high-protein foods. Geriatr Gerontol Int 2025; 25: 173-181.

Global hotspots and trends of nutritional supplements for sick populations from 2000 to 2024

Background

Nutritional supplements (NS) can help patients by providing various nutrients such as essential vitamins and minerals, helping to prevent and recover from diseases. This study provides a broad overview of the field of NS for sick people through bibliometrics and visualization analysis, to analyze the status and development dynamics, explore the popular research questions and directions, and reveal the development trends and research frontiers.

Methods

We searched the Web of Science Core Collection databases for literature related to NS for diseased populations from 2000 to 2024. A total of 1,550 articles were included in the analysis after screening. Analyses performed using CiteSpace and VOSviewer software.

Results

The field of NS for the sick population has witnessed an overall rapid growth in the number of publications, which is divided into three phases: 2000-2008 was the exploratory phase, 2009-2017 was the sustained development phase, and 2018 to date is in the rapid development phase. Research focuses on dietary supplementation, oxidative stress, in vitro injections, development, antioxidant activity, double-blind trials, lipid supplements, functional foods, the health of diseased populations, and the risks of NS.

Conclusion

Different supplements each possess unique benefits and should be chosen according to the type of disease to ensure they contain the corresponding nutrients. Vitamin supplements are widely mentioned among patient populations across the globe. Future trends may focus on applying nutritional supplements in gut microbiota and bioactive compounds. Researchers frequently mention the application of NS in women, infants, and children. It should continue to be monitored and optimized in the future to enhance its therapeutic effects, thereby accelerating patients' recovery and improving their quality of life.

Supplementation with essential amino acids in the early stage of carbohydrate reintroduction after a very-low energy ketogenic therapy (VLEKT) improves body cell mass, muscle strength and inflammation

BACKGROUND

Although little is yet known about the long-term maintenance of very low-energy ketogenic therapy (VLEKT) effects on body composition, muscle strength and inflammation, it is plausible to assume that changes may occur, particularly during the steps following the ketogenic step, due to the loss of the protective effects of ketones and the concomitant reintroduction of carbohydrates. For this reason, the present study aimed to evaluate the effects of supplementation with 8 g per day of essential amino acids (EAAs) on these parameters.

METHODS

A total of 68 women of reproductive age and with grade I obesity who had completed 45 days of the ketogenic phase with VLEKT (KeNuT protocol) and 40 days of non-ketogenic phase of KeNuT protocol with VLEKT (phase 3, fruit reintroduction) were included in the study. Half of them (n = 34) followed this first step of the re-educational phase of KeNuT protocol with VLEKT with supplementation with EAAs (Aminotrofic®: 4 g twice daily). Anthropometric parameters, body composition via bioelectrical impedance analysis and high-sensitivity C-reactive protein (hs-CRP) levels were assessed at baseline, pre- and post both dietary interventions.

RESULTS

At the end of 45 days of ketogenic phase with VLEKT (before fruit reintroduction and EAA supplementation), the two groups did not differ in any of the parameters assessed. At the end of the fruit reintroduction phase, the supplemented group showed greater magnitudes of reduction in weight, waist circumference, fat mass (FM) and hs-CRP (p < 0.001 for all) and of increase in muscle strength (p < 0.001), phase angle (p < 0.001), body cell mass (BCM) (p = 0.001), and muscle mass (%) (p < 0.001).

CONCLUSION

These results underline the usefulness of supplementation with EAAs during the first transitional phase post VLEKT to improve body composition (specifically reduction in FM and increase in BCM), muscle strength, and inflammatory status.

Postprandial Aminoacidemia Following the Ingestion of Alternative and Sustainable Proteins in Humans: A Narrative Review

There is a pressing need to expand the production and consumption of alternative protein sources from plants, fungi, insects, and algae from both nutritional and sustainability perspectives. It is well known that the postprandial rise in plasma amino acid concentrations and subsequent muscle anabolic response is greater after the ingestion of animal-derived protein sources, such as dairy, meat, and eggs, than plant-based proteins. However, emerging evidence shows that a similar muscle anabolic response is observed-despite a lower and slower postprandial aminoacidemia-after the ingestion of alternative protein sources compared with animal-derived protein sources. Therefore, a comprehensive analysis of plasma amino acid kinetics after the ingestion of alternative protein sources would play a significant role in recognizing and identifying the anabolic properties of these protein sources, allowing for the implementation of the best nutritional intervention strategies, contributing to more sustainable food production, and developing new medical nutritional products with optimal impacts on muscle mass, strength, and function, both in terms of health and disease. Therefore, this narrative review is focused on postprandial amino acid kinetics (the area under the curve, peak, and time to reach the peak concentration of amino acids) based on experimental randomized controlled trials performed in young and older adults following the ingestion of different novel, sustainable, and alternative protein sources.

The Etiology of Reduced Muscle Mass with Surgical and Pharmacological Weight Loss and the Identification of Potential Countermeasures

Obesity represents a major health crisis in the United States, significantly increasing risks for chronic diseases and generating substantial economic costs. While bariatric surgery and pharmacological interventions such as GLP-1 receptor agonists have been proven effective in achieving substantial weight loss and improving comorbid conditions, they also raise concerns about the unintended loss of fat-free mass, particularly muscle. This loss of muscle mass compromises physical functionality, quality of life, and long-term metabolic health, particularly in individuals with sarcopenic obesity or those at risk of frailty. To sustain strength, mobility, and metabolic function during weight loss interventions, the preservation of muscle mass is essential. However, current weight-loss strategies often fail to adequately address the need to maintain fat-free mass. This review explores the physiological mechanisms governing muscle mass, the impact of obesity and rapid weight loss on muscle protein turnover, and nutritional and age-based strategies that may help protect muscle during intentional weight reduction. By focusing on these critical countermeasures, this review aims to inform future clinical practice and research initiatives with the long-term goal of achieving effective weight loss through reduction in fat tissue while preserving skeletal muscle mass, enhancing health outcomes, and long-term functionality in patients undergoing significant weight reduction.

The effects of branched-chain amino acids on muscle protein synthesis, muscle protein breakdown and associated molecular signalling responses in humans: an update

Branched-chain amino acids (BCAA: leucine, isoleucine and valine) are three of the nine indispensable amino acids, and are frequently consumed as a dietary supplement by athletes and recreationally active individuals alike. The popularity of BCAA supplements is largely predicated on the notion that they can stimulate rates of muscle protein synthesis (MPS) and suppress rates of muscle protein breakdown (MPB), the combination of which promotes a net anabolic response in skeletal muscle. To date, several studies have shown that BCAA (particularly leucine) increase the phosphorylation status of key proteins within the mechanistic target of rapamycin (mTOR) signalling pathway involved in the regulation of translation initiation in human muscle. Early research in humans demonstrated that BCAA provision reduced indices of whole-body protein breakdown and MPB; however, there was no stimulatory effect of BCAA on MPS. In contrast, recent work has demonstrated that BCAA intake can stimulate postprandial MPS rates at rest and can further increase MPS rates during recovery after a bout of resistance exercise. The purpose of this evidence-based narrative review is to critically appraise the available research pertaining to studies examining the effects of BCAA on MPS, MPB and associated molecular signalling responses in humans. Overall, BCAA can activate molecular pathways that regulate translation initiation, reduce indices of whole-body and MPB, and transiently stimulate MPS rates. However, the stimulatory effect of BCAA on MPS rates is less than the response observed following ingestion of a complete protein source providing the full complement of indispensable amino acids.

Underpowered studies in muscle metabolism research: Determinants and considerations

Biomedical research frequently employs null hypothesis testing to determine whether an observed difference in a sample is likely to exist in the broader population. Null hypothesis testing generally assumes that differences between groups or interventions are non-existent, unless proven otherwise. Because biomedical studies with human subjects are often limited by financial and logistical resources, they tend to have low statistical power, i.e. a low probability of statistically confirming a true difference. As a result, small but potentially clinically important differences may be overseen or ignored simply due to the absence of a statistically significant difference. This absence is often misinterpreted as 'equivalence' of treatments. In this educational paper, we will use practical examples related to the effects of exercise and nutrition on muscle protein metabolism to illustrate the most important determinants of statistical power, as well as their implications for both investigators and readers of scientific articles. Changes in muscle mass occur at a relatively slow rate, making it practically challenging to detect differences between treatment groups in a long-term setting. One way to make it 'easier' to differentiate between groups and hence increase statistical power is to have a sufficiently long study duration to allow treatment effects to become apparent. This is especially relevant when comparing treatments with relatively small expected differences such as the effect of modest changes in daily protein intake. Secondly, one could try to minimize the variance and response heterogeneity within groups, for example by using strict inclusion criteria and standardization protocols (e.g., meal provision), by using cross-over designs, or even within-subject designs where two interventions are compared simultaneously (e.g., studying an exercised limb vs a contralateral control limb) although this might limit the generalizability of the findings (e.g. such single-limb exercise training is not common in practice). In terms of data interpretation, investigators should obviously refrain from drawing strong conclusions from underpowered studies. Yet, such studies still provide valuable data for meta-analyses. Finally, because muscle protein synthesis rates are highly responsive to anabolic stimuli, acute metabolic studies are more sensitive to detect potentially clinically relevant differences in the anabolic response between treatments. Apart from further elaborating on these topics, this educational article encourages readers to more critically question null findings and scientists to more clearly discuss limitations that may have compromised statistical power.

Collagen Peptide Supplementation during Training Does Not Further Increase Connective Tissue Protein Synthesis Rates

INTRODUCTION

Protein supplementation increases postexercise muscle protein synthesis rates and, as such, supports exercise-induced muscle conditioning. Collagen protein has been suggested as the preferred protein source to stimulate muscle connective protein synthesis rates during recovery from exercise. Here we assessed the effects of hydrolyzed collagen peptide supplementation on both myofibrillar as well as muscle connective protein synthesis rates during 1 wk of strenuous resistance exercise training.

METHODS

In a randomized, double-blind, parallel design, 25 young men (24 ± 3 yr, 76.9 ± 6.4 kg) were selected to perform 1 wk of intense resistance-type exercise training. Subjects were randomly assigned into two groups receiving either 15 g hydrolyzed collagen peptides (COL) or a noncaloric placebo (PLA) twice daily during the intervention. Subjects were administered deuterated water ( 2 H 2 O) daily, with blood and skeletal muscle tissue samples being collected before and after the intervention to determine daily myofibrillar and muscle connective protein synthesis rates.

RESULTS

Post-absorptive plasma glycine, proline, and hydroxyproline concentrations increased following collagen peptide supplementation ( P < 0.05) and showed higher levels when compared with the placebo group ( P < 0.05). Daily muscle connective protein synthesis rates during the intervention period exceeded myofibrillar protein synthesis rates (1.99 ± 0.38 vs 1.34 ± 0.23%·d -1 , respectively; P < 0.001). Collagen peptide supplementation did not result in higher myofibrillar or muscle connective protein synthesis rates (1.34 ± 0.19 and 1.97 ± 0.47%·d -1 , respectively) when compared with the placebo group (1.34 ± 0.27 and 2.00 ± 0.27%·d -1 , respectively; P > 0.05).

CONCLUSIONS

Collagen peptide supplementation (2 × 15 g daily) does not increase myofibrillar or muscle connective protein synthesis rates during 1 wk of intense resistance exercise training in young, recreational athletes.

Consideration of the role of protein quality in determining dietary protein recommendations

The quality of a dietary protein refers to its ability to provide the EAAs necessary to meet dietary requirements. There are 9 dietary amino acids that cannot be metabolically produced in the body and therefore must be consumed as part of the diet to avoid adverse metabolic consequences. These essential amino acids (EAAs) serve a variety of roles in the body. The amount and profile of the dietary EAAs relative to the individual EAA requirements and the digestibility of the dietary protein are the key factors that determine its quality. Currently the Digestible Indispensable Amino Acid Score (DIAAS) is the best available approach to quantifying protein quality. The most prominent metabolic role of dietary EAAs is to stimulate protein synthesis by serving as signals to activate molecular mechanisms responsible for the initiation of protein synthesis and, most importantly, to provide the necessary precursors for the synthesis of complete proteins. Current dietary recommendations generally do not consider protein quality. Accounting for protein quality in dietary patterns can be accomplished while staying within established ranges for dietary protein consumption. Poor protein quality can be compensated for to some extent by eating more low-quality protein, but to be effective ("complementary") the limiting EAA must differ between the low-quality protein and the base diet to which it is being supplemented. Adding a high-quality protein to a dietary pattern based on low-quality protein is more effective in meeting EAA goals than increasing the amount of low-quality protein, even if the low-quality proteins are complementary. Further, reliance entirely on low-quality protein food sources, particularly in circumstances that may benefit from a level of dietary EAAs greater than minimal requirements, is likely to include excessive caloric consumption. While protein consumption in high-income nations is generally perceived to be adequate or even excessive, assessment of dietary patterns indicates that a significant percentage of individuals may fall short of meeting optimal levels of EAA consumption, especially in circumstances such as aging in which the optimal EAA consumption is greater than basal values for healthy young individuals. The case is made that protein quality is an important consideration in meeting EAA requirements.

Gut microbiota modulation and amino acid absorption by Lactiplantibacillus plantarum TWK10 in pea protein ingestion: TWK10 boosts hut microbiota, amino acid uptake

For vegetarians or vegan athletes, improving the utilization of plant-based protein and the absorption of amino acids is crucial. This study explored the impact of combining pea protein with Lactiplantibacillus plantarum TWK10 and resistance training on amino acid absorption and exercise performance. Sixteen male and sixteen female participants were randomly assigned to either a control group (20 g of pea protein without TWK10) or a TWK10 group (20 g of pea protein combined with 1 × 1010 colony-forming units of TWK10). After 28 days of supplementation combined with resistance exercise training three times per week. All subjects underwent body composition and muscle strength performance, plasma and fecal samples were collected for microbiota analysis and blood amino acid concentrations. The TWK10 group showed a significant increase in muscle thickness and improvements were observed in 1 repetition maximum bench press, explosive, anaerobic power output compared to before the intervention, and were significantly higher than those in the control group (p < 0.05). TWK10 supplementation significantly increased the area under the curve and maximum concentration of branched-chain amino acids, essential amino acids, and total amino acids (p < 0.05). Furthermore, TWK10 supplementation effectively increased the richness of gut bacterial families. Our study demonstrated that the TWK10 significant increase in the abundance of specific bacterial families in the gut, resulting in increased pea protein amino acid absorption. Moreover, increasing muscle mass and significantly improving muscle thickness, muscle strength, power, and anaerobic capacity.

Short-term intermittent fasting and energy restriction do not impair rates of muscle protein synthesis: A randomised, controlled dietary intervention

BACKGROUND

Intermittent fasting (IF) is an effective energy restricted dietary strategy to reduce body and fat mass and improve metabolic health in individuals with either an overweight or obese status. However, dietary energy restriction may impair muscle protein synthesis (MPS) resulting in a concomitant decline in lean body mass. Due to periods of prolonged fasting combined with irregular meal intake, we hypothesised that IF would reduce rates of MPS compared to an energy balanced diet with regular meal patterns.

AIMS

We assessed the impact of a short-term, ten days, alternate day fasting or a continuous energy restricted diet to a control diet on integrated rates of skeletal MPS in middle-aged males with overweight or obesity.

METHODS

Twenty-seven middle-aged males with overweight or obesity (age: 44.6 ± 5.4 y; BMI: 30.3 ± 2.6 kg/m2) consumed a three-day lead-in diet, followed by a ten-day controlled dietary intervention matched for protein intake, as alternate day fasting (ADF: 62.5 energy (En)%, days of 25 En% alternated with days of 100 En% food ingestion), continuous energy restriction (CER: 62.5 En%), or an energy balanced, control diet (CON: 100 En%). Deuterated water (D2O) methodology with saliva, blood, and skeletal muscle sampling were used to assess integrated rates of MPS over the ten-day intervention period. Secondary measures included fasting plasma glucose, insulin, and gastrointestinal hormone concentrations, continuous glucose monitoring, and assessment of body composition.

RESULTS

There were no differences in daily rates of MPS between groups (ADF: 1.18 ± 0.13, CER: 1.13 ± 0.16, and CON: 1.18 ± 0.18 %/day, P > 0.05). The reductions in body mass were greater in ADF and CER compared to CON (P < 0.001). Lean and fat mass were decreased by a similar magnitude across groups (main time effect, P < 0.001; main group effect, P > 0.05). Fasting plasma leptin concentrations decreased in ADF and CER (P < 0.001), with no differences in fasting plasma glucose or insulin concentrations between groups.

CONCLUSION

Short-term alternate day fasting does not lower rates of MPS compared to continuous energy restriction or an energy balanced, control diet with matched protein intake. The prolonged effects of IF and periods of irregular energy and protein intake patterns on muscle mass maintenance remain to be investigated. This trial was registered under Australian New Zealand Clinical Trial Registry (https://www.anzctr.org.au), identifier no. ACTRN12619000757112.

Effect of synchronicity of amino acid supply on the synthesis of protein in C2C12 myotubes cultured in vitro

Previous studies inferred that the synthesis rate/efficiency of protein in body tissue is probably affected by synchronicity of different amino acid (AA) supply in its metabolic pool. In order to further observe the influence of synchronicity of AA supply on the synthesis of protein in cell level, a cell culture experiment in vitro was conducted with C2C12 myotubes. C2C12 myotubes were cultured for 24 h, meanwhile the culture medium was replaced for each 8 h. Those myotubes were subjected to 3 treatments (1 for controlled and 2 for tested), control myotubes were cultured with same normal complete medium within the whole 24 h, and the 2 tested myotubes were cultured with asynchronous amino acid supply medium in which the levels of different AAs (Lysine, threonine, methionine, leucine, valine and glutamic acid) either increased and then decreased or decreased and then increased, at different replaced medium time point (at 0, 8, and 16 h). However, during the whole experiment period all the 3 treated myotubes received same amount of each AA. The sample of the myotubes were used for myotube morphology, protein, AA, and proteomic analysis. The results showed that asynchronous AA nutrition affect the synthesis and degradation of myotube proteins, and the AAAS in the medium increase, thus decreasing the synthesis rate of myotube proteins (p < 0.05) and decreasing the diameter of myotubes (p < 0.05). The process of reduced protein synthesis affects the PI3K-AKT and FoxO signaling pathway by downregulating the levels of IRS1 and EGFR, and the degradation amplitude is greater than the synthesis amplitude. Therefore, this study further revealed the effect of the asynchronous supply of amino acids on myotube protein synthesis and the underlying mechanism and provided a theoretical reference for the precision of nutrition to animals.

Efficacy of a combined exercise and nutrition intervention study for outpatients with possible sarcopenia in community-based primary care clinics (ENdSarC): study protocol for a multicenter single-blinded randomized controlled trial

BACKGROUND

Sarcopenia is a geriatric disease characterized by loss of muscle mass and strength. Although combined exercise and nutrition intervention are known to be effective for sarcopenia, clinical trials involving outpatients with sarcopenia in primary care are scarce. We describe a protocol for a trial to examine the effects of a 12-week combined exercise and nutrition intervention in Korean older adults with possible sarcopenia in community-based primary care.

METHODS

This multicenter, randomized, controlled trial will include 94 community-dwelling older outpatients aged 65-85 years with possible sarcopenia (47 participants in the intervention and control groups each). Resistance exercises, which incorporate concentric and eccentric exercises, will consist of an introductory phase (3 weeks: twice-weekly supervised exercise sessions and once-weekly home exercises; contraction exercises), an expanded phase (3 weeks: twice-weekly supervised exercise sessions and once-weekly home exercises; eccentric exercises), and a maintenance phase (6 weeks: once-weekly supervised exercise sessions and twice-weekly home exercises; power/eccentric exercises). Nutritional supplementation will be provided according to the nutritional status of the participants using a Mini-Nutritional Assessment. Participants will be assessed at baseline, 12 and 24 weeks, and the primary outcome will be the 5-times chair stand test results.

DISCUSSION

To the best of our knowledge, this will be the first clinical trial to evaluate the efficacy of a combined exercise and nutritional supplementation intervention in older outpatients with possible sarcopenia in community-based primary care clinics. These findings will provide new insights to clinicians regarding the long-term usability for doctors and outpatients with possible sarcopenia in community-based primary care.

TRIAL REGISTRATION

This trial was prospectively registered at ClinicalTrials.gov on September 16, 2023 (registration number: NCT06049914).

Antioxidative, Glucose Management, and Muscle Protein Synthesis Properties of Fish Protein Hydrolysates and Peptides

The marine environment is an excellent source for many physiologically active compounds due to its extensive biodiversity. Among these, fish proteins stand out for their unique qualities, making them valuable in a variety of applications due to their diverse compositional and functional properties. Utilizing fish and fish coproducts for the production of protein hydrolysates and bioactive peptides not only enhances their economic value but also reduces their potential environmental harm, if left unutilized. Fish protein hydrolysates (FPHs), known for their excellent nutritional value, favorable amino acid profiles, and beneficial biological activities, have generated significant interest for their potential health benefits. These hydrolysates contain bioactive peptides which are peptide sequences known for their beneficial physiological effects. These biologically active peptides play a role in metabolic regulation/modulation and are increasingly seen as promising ingredients in functional foods, nutraceuticals and pharmaceuticals, with potential to improve human health and prevent disease. This review aims to summarize the current in vitro, cell model (in situ) and in vivo research on the antioxidant, glycaemic management and muscle health enhancement properties of FPHs and their peptides.

Postprandial plasma aminoacidemia and indices of appetite regulation following pea-rice blend, pea isolate and whey protein ingestion in healthy young adults

Plant-derived proteins are often deficient in essential amino acids and have lower rates of digestibility than animal-derived proteins. Blending different plant-derived proteins could compensate for these deficiencies and may augment postprandial aminoacidemia over single-source plant proteins. This study assessed plasma amino acids and appetite hormones, appetite sensations and ad libitum energy intake following ingestion of a pea-rice protein blend (BLEND), compared with pea-only (PEA) and whey (WHEY) protein. In a randomised, double-blind, crossover design, ten healthy adults (M n 4, F n 6; mean (sd) age 22 (sd 3) years; BMI 24 (sd 3) kg·m2) ingested 0·3 g·kg·body mass-1 of BLEND, PEA or WHEY. Arterialised venous blood samples and appetite ratings were obtained in the fasted state and over 240 min postprandially. Energy intake was measured via an ad libitum buffet-style test meal. Mean plasma essential amino acid incremental AUC was higher in WHEY, compared with PEA (P < 0·01; mean diff (95 % CI): 44 218 (15 806, 72 631) μmol·240 min·l-1) and BLEND (P < 0·01; 14 358 (16 031, 101 121) μmol·240 min·l-1), with no differences between PEA and BLEND (P = 0·67). Plasma ghrelin and glucagon-like peptide-1, appetite ratings and ad libitum energy intake responses did not differ between treatments (P > 0·05 for all). Ingestion of a pea-rice protein blend did not augment postprandial aminoacidemia above pea protein, perhaps attributable to marginal differences in essential amino acid composition. No between-treatment differences in appetite or energy intake responses were apparent, suggesting that the influence of protein ingestion on perceived appetite ratings and orexigenic hormonal responses may not be solely determined by postprandial plasma aminoacidemia.

Role of Peripheral Parenteral Nutrition Composition on Clinical Outcomes in Patients Undergoing Gastrectomy or Colectomy: A Phase III Indian Clinical Trial

Aims and background

Various types of parenteral nutritional products exist, each with specific formulations designed to meet the diverse nutritional needs of patient's post-abdominal surgery. Here, two different parenteral nutrition (PN) solutions BFLUID and NUTRIFLEX PERI are compared in terms of therapeutic efficacy and safety profile.

Materials and methods

A prospective, multi-center, randomized, parallel-group, non-inferiority Phase III clinical trial compared two PN solutions namely BFLUID (N = 78) and NUTRIFLEX PERI (N = 72) in 150 patients undergoing gastrectomy or colectomy. Primary endpoints included length of hospital stay while secondary endpoints included assessment and comparison of length of ICU/HDU stay, assessment of incidents of infections and mortality, change in blood levels of vitamin B1, change in nutritional parameters, thrombophlebitis, pain at the injection site, and recording of adverse events (AEs).

Results

There was no significant difference in terms of length of hospital stay, length of ICU/HDU stay as well as changes in nutritional parameters from baseline and change in blood levels of vitamin B1 from baseline. Both study groups exhibited comparability in terms of AEs, pain at the injection site, and the incidence of phlebitis. There was no significant difference in the number and severity of adverse events reported in both groups. Additionally, no signs of infection were observed in patients from either group.

Conclusion

The trial successfully demonstrated the non-inferiority of BFLUID to NUTRIFLEX PERI. Moreover, the results indicated that PN enriched with high levels of branched-chain amino acids (BCAAs), essential amino acids (EAAs), and thiamine is both safe and efficacious for adult patients undergoing gastrectomy or colectomy.

How to cite this article

Goyal A, Pathak A, BS Madhu, Soni H, Bhatt K, Raju KVVN, et al. Role of Peripheral Parenteral Nutrition Composition on Clinical Outcomes in Patients Undergoing Gastrectomy or Colectomy: A Phase III Indian Clinical Trial. Indian J Crit Care Med 2024;28(9):871-878.

Nutritional Considerations During Major Weight Loss Therapy: Focus on Optimal Protein and a Low-Carbohydrate Dietary Pattern

PURPOSE OF REVIEW

Considering the high prevalence of obesity and related metabolic impairments in the population, the unique role nutrition has in weight loss, reversing metabolic disorders, and maintaining health cannot be overstated. Normal weight and well-being are compatible with varying dietary patterns, but for the last half century there has been a strong emphasis on low-fat, low-saturated fat, high-carbohydrate based approaches. Whereas low-fat dietary patterns can be effective for a subset of individuals, we now have a population where the vast majority of adults have excess adiposity and some degree of metabolic impairment. We are also entering a new era with greater access to bariatric surgery and approval of anti-obesity medications (glucagon-like peptide-1 analogues) that produce substantial weight loss for many people, but there are concerns about disproportionate loss of lean mass and nutritional deficiencies.

RECENT FINDINGS

No matter the approach used to achieve major weight loss, careful attention to nutritional considerations is necessary. Here, we examine the recent findings regarding the importance of adequate protein to maintain lean mass, the rationale and evidence supporting low-carbohydrate and ketogenic dietary patterns, and the potential benefits of including exercise training in the context of major weight loss. While losing and sustaining weight loss has proven challenging, we are optimistic that application of emerging nutrition science, particularly personalized well-formulated low-carbohydrate dietary patterns that contain adequate protein (1.2 to 2.0 g per kilogram reference weight) and achieve the beneficial metabolic state of euketonemia (circulating ketones 0.5 to 5 mM), is a promising path for many individuals with excess adiposity.

Association of dietary patterns with sarcopenia in adults aged 50 years and older

PURPOSE

Although numerous studies have investigated the impact of dietary factors on the prevention of decreased muscle mass and function, limited research has examined the relationship between dietary patterns and sarcopenia. This study aimed to assess the associations between dietary patterns, and sarcopenia, muscle strength, and mass in adults following a Mediterranean diet residing in southern Italian cities.

METHODS

This cross-sectional study utilized data from an existing database, comprising 528 individuals aged 50 years or older who underwent health-screening tests at the Clinical Nutrition Unit of the "R.Dulbecco" University Hospital. Strength was assessed through handgrip strength, and appendicular skeletal muscle mass was estimated using bioelectrical impedance analysis. Dietary intake information was collected through a food frequency questionnaire linked to the MetaDieta 3.0.1 nutrient composition database. Principal Component Analysis, a statistical technique identifying underlying relationships among different nutrients, was employed to determine dietary patterns. Multinomial logistic regression analysis was conducted to estimate the odds ratio for sarcopenia or low handgrip strength in relation to the lowest tertile of dietary pattern adherence compared to the highest adherence.

RESULTS

The participants had a mean age of 61 ± 8 years. Four dietary patterns were identified, with only the Western and Mediterranean patterns showing correlations with handgrip strength and appendicular skeletal muscle mass. However, only the Mediterranean pattern exhibited a correlation with sarcopenia (r =  - 0.17, p = 0.02). The highest tertile of adherence to the Mediterranean dietary pattern demonstrated significantly higher handgrip strength compared to the lowest tertile (III Tertile: 28.3 ± 0.5 kg vs I Tertile: 26.3 ± 0.5 kg; p = 0.01). Furthermore, even after adjustment, the highest tertile of adherence to the Mediterranean pattern showed a significantly lower prevalence of sarcopenia than the lowest adherence tertile (4% vs 16%, p = 0.04). The lowest adherence to the Mediterranean dietary pattern was associated with increased odds of having low muscle strength (OR = 2.38; p = 0.03; 95%CI = 1.05-5.37) and sarcopenia (OR = 9.69; p = 0.0295; %CI = 1.41-66.29).

CONCLUSION

A high adherence to the Mediterranean dietary pattern, characterized by increased consumption of legumes, cereals, fruits, vegetables, and limited amounts of meat, fish, and eggs, is positively associated with handgrip strength and appendicular skeletal muscle mass. The highest adherence to this dietary model is associated with the lowest odds of low muscle strength and sarcopenia. Despite the changes brought about by urbanization in southern Italy compared to the past, our findings continue to affirm the superior benefits of the Mediterranean diet in postponing the onset of frailty among older adults when compared to other dietary patterns that are rich in animal foods.

Plant Protein Blend Ingestion Stimulates Postexercise Myofibrillar Protein Synthesis Rates Equivalently to Whey in Resistance-Trained Adults

PURPOSE

Whey protein ingestion is typically considered an optimal dietary strategy to maximize myofibrillar protein synthesis (MyoPS) after resistance exercise. Although single-source plant protein ingestion is typically less effective, at least partly, due to less favorable amino acid profiles, this could theoretically be overcome by blending plant-based proteins with complementary amino acid profiles. We compared the postexercise MyoPS response after the ingestion of a novel plant-derived protein blend with an isonitrogenous bolus of whey protein.

METHODS

Ten healthy, resistance-trained, young adults (male/female: 8/2; age: 26 ± 6 yr; BMI: 24 ± 3 kg·m -2 ) received a primed continuous infusion of L-[ ring - 2 H 5 ]-phenylalanine and completed a bout of bilateral leg resistance exercise before ingesting 32 g protein from whey (WHEY) or a plant protein blend (BLEND; 39.5% pea, 39.5% brown rice, 21.0% canola) in a randomized, double-blind crossover fashion. Blood and muscle samples were collected at rest, and 2 and 4 h after exercise and protein ingestion, to assess plasma amino acid concentrations, and postabsorptive and postexercise MyoPS rates.

RESULTS

Plasma essential amino acid availability over the 4 h postprandial postexercise period was ~44% higher in WHEY compared with BLEND ( P = 0.04). From equivalent postabsorptive values (WHEY, 0.042 ± 0.020%·h -1 ; BLEND, 0.043 ± 0.015%·h -1 ) MyoPS rates increased after exercise and protein ingestion (time effect; P < 0.001) over a 0- to 2-h period (WHEY, 0.085 ± 0.037%·h -1 ; BLEND, 0.080 ± 0.037%·h -1 ) and 2- to 4-h period (WHEY, 0.085 ± 0.036%·h -1 ; BLEND, 0.086 ± 0.034%·h -1 ), with no differences between conditions during either period or throughout the entire (0-4 h) postprandial period (time-condition interactions; all P > 0.05).

CONCLUSIONS

Ingestion of a novel plant-based protein blend stimulates postexercise MyoPS to an equivalent extent as whey protein, demonstrating the utility of plant protein blends to optimize postexercise skeletal muscle reconditioning.

Associations between Essential Amino Acid Intake and Functional Health Outcomes in Older Adults: Analysis of the National Health and Nutrition Examination Survey, 2001-2018

Background

The relationships between habitual essential amino acid (EAA) intake and body composition, muscle strength, and physical function in older US adults are not well defined.

Objectives

This cross-sectional study evaluated associations between usual EAA intakes and body composition, muscle strength, and physical function in US adults ≥65 y.

Methods

The Food and Nutrient Database for Dietary Studies (FNDDS) 2001-2018 was linked to the US Department of Agriculture Standard Reference database to access existing amino acid composition data for FNDDS ingredients. FNDDS ingredients without existing amino acid composition data were matched to similar ingredient codes with available data. Usual EAA, leucine, lysine, and sulfur-containing amino acid (SAA; methionine + cysteine) intakes (g/d) from National Health and Nutrition Examination Survey 2001-2018 were calculated for individuals ≥65 y (n = 10,843). Dependent variables included muscle strength measured by isometric grip test, body mass index (BMI), waist circumference, dual-energy X-ray absorptiometry-measured appendicular lean mass and whole-body fat mass, and self-reported physical function (that is, tasks of daily living). Regression analyses were used to determine covariate-adjusted relationships between EAA, leucine, lysine, and SAA intake and functional health outcomes. P < 0.0013 was considered significant.

Results

EAA, leucine, lysine, and SAA intakes, covaried with physical activity level and usual protein intake, were not associated with muscle strength or self-reported physical function in males or females or with body composition in males. EAA intakes were positively associated with waist circumference in females (β ± SEM, 2.1 ± 0.6 cm, P = 0.0007). Lysine intakes were positively associated with BMI (3.0 ± 0.7 kg/m2, P < 0.0001) and waist circumference (7.0 ± 1.7 cm, P = 0.0001) in females.

Conclusions

Habitual EAA, leucine, lysine, and SAA intakes, covaried with physical activity level and usual protein intake, were not associated with lean mass, muscle strength, or physical function in adults ≥65 y. However, EAA intakes, particularly lysine, were positively associated with measures of adiposity in older females.This trial was registered with the Open Science Framework (https://doi.org/10.17605/OSF.IO/25V63) as osf.io/25v63).

Dietary Protein and Physical Exercise for the Treatment of Sarcopenia

Sarcopenia is a multifactorial age-related disorder that causes a decrease in muscle mass, strength, and function, leading to alteration of movement, risk of falls, and hospitalization. This article aims to review recent findings on the factors underlying sarcopenia and the strategies required to delay and counteract its symptoms. We focus on molecular factors linked to ageing, on the role of low-grade chronic and acute inflammatory conditions such as cancer, which contributes to the onset of sarcopenia, and on the clinical criteria for its diagnosis. The use of drugs against sarcopenia is still subject to debate, and the suggested approaches to restore muscle health are based on adequate dietary protein intake and physical exercise. We also highlight the difference in the amount and quality of amino acids within animal- and plant-based diets, as studies have often shown varying results regarding their effect on sarcopenia in elderly people. In addition, many studies have reported that non-pharmacological approaches, such as an optimization of dietary protein intake and training programs based on resistance exercise, can be effective in preventing and delaying sarcopenia. These approaches not only improve the maintenance of skeletal muscle function, but also reduce health care costs and improve life expectancy and quality in elderly people.

Oral tribology of dairy protein-rich emulsions and emulsion-filled gels affected by colloidal processing and composition

Designing nutritious food for the elderly population often requires significant quantities of leucine-rich whey proteins to combat malnutrition, yet high-protein formulations can cause mouth dryness and increased oral friction. This study investigated how various colloidal processing methods and compositions impact the in vitro oral tribological properties of protein-rich emulsions and emulsion-filled gels. Oil-in-water emulsions with oil fractions from 1 wt% to 20 wt% were prepared, alongside emulsion-filled gels containing whey protein isolate (WPI), hydrolysed whey protein (HWP), or a blend of both (10 wt% protein content). Two processing approaches were employed: creating emulsions with an initial 10 w% protein content (M1) and initially forming emulsions with 0.1 wt% protein content, then enriching to a final 10 wt% concentration (M2). The hypothesis was that formulations with HWP or method 2 (M2) would offer lubrication benefits by inducing droplet coalescence, aiding in the formation of a lubricating boundary tribofilm. Surprisingly, the tribological behavior of high-protein emulsions showed minimal dependence on oil droplet volume fraction. However, both HWP-based emulsions and those processed with M2 for WPI exhibited significant friction reduction, which may be attributed to the presence of coalesced oil droplets, supporting our hypothesis. Substituting 50 wt% of WPI with HWP in emulsion-filled gel boli resulted in very low friction coefficients in the boundary lubrication regime, suggesting oil droplet release from the gel matrix. These findings provide insights into designing high-protein foods with improved mouthfeel for the elderly population, necessitating further validation through sensory studies.

New insights into healthy ageing, inflammageing and frailty using metabolomics

Human ageing is a normal process and does not necessarily result in the development of frailty. A mix of genetic, environmental, dietary, and lifestyle factors can have an impact on ageing, and whether an individual develops frailty. Frailty is defined as the loss of physiological reserve both at the physical and cellular levels, where systemic processes such as oxidative stress and inflammation contribute to physical decline. The newest "omics" technology and systems biology discipline, metabolomics, enables thorough characterisation of small-molecule metabolites in biological systems at a particular time and condition. In a biological system, metabolites-cellular intermediate products of metabolic reactions-reflect the system's final response to genomic, transcriptomic, proteomic, epigenetic, or environmental alterations. As a relatively newer technique to characterise metabolites and biomarkers in ageing and illness, metabolomics has gained popularity and has a wide range of applications. We will give a comprehensive summary of what is currently known about metabolomics in studies of ageing, with a focus on biomarkers for frailty. Metabolites related to amino acids, lipids, carbohydrates, and redox metabolism may function as biomarkers of ageing and/or frailty development, based on data obtained from human studies. However, there is a complexity that underpins biological ageing, due to both genetic and environmental factors that play a role in orchestrating the ageing process. Therefore, there is a critical need to identify pathways that contribute to functional decline in people with frailty.

Digestible indispensable amino acid score (DIAAS): 10 years on

The objective of the review is to revisit the findings of the 2011 Food and Agriculture Organization of the United Nations (FAO) Expert Consultation on Dietary Protein Quality Evaluation in Human Nutrition, and to report on progress on uptake of the findings. It is evident that since 2011 there has been a concerted research effort to enhance an understanding of the protein quality of foods. The validity of the growing pig ileal protein digestibility assay has been confirmed and numerous studies reported using the growing pig as a model to give true ileal amino acid digestibility values for foods as consumed by humans. This has allowed for the determination of digestible indispensable amino acid scores (DIAAS) for a range of foods. A new non-invasive true ileal amino acid digestibility assay in humans which can be applied in different physiological states, called the dual-isotope assay, has been developed and applied to determine the DIAAS values of foods. It is concluded that DIAAS is currently the most accurate score for routinely assessing the protein quality rating of single source proteins. In the future, the accuracy of DIAAS can be enhanced by improved information on: the ideal dietary amino acid balance including the ideal dispensable to indispensable amino acid ratio; dietary indispensable amino acid requirements; effects of processing on ileal amino acid digestibility and lysine bioavailability. There is a need to develop rapid, inexpensive in vitro digestibility assays. Conceptual issues relating DIAAS to food regulatory claims, and to holistic indices of food nutritional and health status are discussed. The first recommendation of the 2011 Consultation regarding treating each indispensable amino acid as an individual nutrient has received little attention. Consideration should be given to providing food label information on the digestible contents of specific indispensable amino acids.

Higher Muscle Protein Synthesis Rates Following Ingestion of an Omnivorous Meal Compared with an Isocaloric and Isonitrogenous Vegan Meal in Healthy, Older Adults

BACKGROUND

Plant-derived proteins are considered to have fewer anabolic properties when compared with animal-derived proteins. The anabolic properties of isolated proteins do not necessarily reflect the anabolic response to the ingestion of whole foods. The presence or absence of the various components that constitute the whole-food matrix can strongly impact protein digestion and amino acid absorption and, as such, modulate postprandial muscle protein synthesis rates. So far, no study has compared the anabolic response following ingestion of an omnivorous compared with a vegan meal.

OBJECTIVES

This study aimed to compare postprandial muscle protein synthesis rates following ingestion of a whole-food omnivorous meal providing 100 g lean ground beef with an isonitrogenous, isocaloric whole-food vegan meal in healthy, older adults.

METHODS

In a randomized, counter-balanced, cross-over design, 16 older (65-85 y) adults (8 males, 8 females) underwent 2 test days. On one day, participants consumed a whole-food omnivorous meal containing beef as the primary source of protein (0.45 g protein/kg body mass; MEAT). On the other day, participants consumed an isonitrogenous and isocaloric whole-food vegan meal (PLANT). Primed continuous L-[ring-13C6]-phenylalanine infusions were applied with blood and muscle biopsies being collected frequently for 6 h to assess postprandial plasma amino acid profiles and muscle protein synthesis rates. Data are presented as means ± standard deviations and were analyzed by 2 way-repeated measures analysis of variance and paired-samples t tests.

RESULTS

MEAT increased plasma essential amino acid concentrations more than PLANT over the 6-h postprandial period (incremental area under curve 87 ± 37 compared with 38 ± 54 mmol·6 h/L, respectively; P-interaction < 0.01). Ingestion of MEAT resulted in ∼47% higher postprandial muscle protein synthesis rates when compared with the ingestion of PLANT (0.052 ± 0.023 and 0.035 ± 0.021 %/h, respectively; paired-samples t test: P = 0.037).

CONCLUSIONS

Ingestion of a whole-food omnivorous meal containing beef results in greater postprandial muscle protein synthesis rates when compared with the ingestion of an isonitrogenous whole-food vegan meal in healthy, older adults. This study was registered at clinicaltrials.gov as NCT05151887.

Changes in the gut microbiota of patients with sarcopenia based on 16S rRNA gene sequencing: a systematic review and meta-analysis

Introduction

Sarcopenia, an age-related disease, has become a major public health concern, threatening muscle health and daily functioning in older adults around the world. Changes in the gut microbiota can affect skeletal muscle metabolism, but the exact association is unclear. The richness of gut microbiota refers to the number of different species in a sample, while diversity not only considers the number of species but also the evenness of their abundances. Alpha diversity is a comprehensive metric that measures both the number of different species (richness) and the evenness of their abundances, thereby providing a thorough understanding of the species composition and structure of a community.

Methods

This meta-analysis explored the differences in intestinal microbiota diversity and richness between populations with sarcopenia and non-sarcopenia based on 16 s rRNA gene sequencing and identified new targets for the prevention and treatment of sarcopenia. PubMed, Embase, Web of Science, and Google Scholar databases were searched for cross-sectional studies on the differences in gut microbiota between sarcopenia and non-sarcopenia published from 1995 to September 2023 scale and funnel plot analysis assessed the risk of bias, and performed a meta-analysis with State v.15. 1.

Results

A total of 17 randomized controlled studies were included, involving 4,307 participants aged 43 to 87 years. The alpha diversity of intestinal flora in the sarcopenia group was significantly reduced compared to the non-sarcopenia group: At the richness level, the proportion of Actinobacteria and Fusobacteria decreased, although there was no significant change in other phyla. At the genus level, the abundance of f-Ruminococcaceae; g-Faecalibacterium, g-Prevotella, Lachnoclostridium, and other genera decreased, whereas the abundance of g-Bacteroides, Parabacteroides, and Shigella increased.

Discussion

This study showed that the richness of the gut microbiota decreased with age in patients with sarcopenia. Furthermore, the relative abundance of different microbiota changed related to age, comorbidity, participation in protein metabolism, and other factors. This study provides new ideas for targeting the gut microbiota for the prevention and treatment of sarcopenia.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=475887, CRD475887.

Effects of Resistance Exercise and Essential Amino Acid Intake on Muscle Quality, Myokine, and Inflammation Factors in Young Adult Males

BACKGROUND

Recently, many studies have been devoted to discovering nutrients for exercise-like effects. Resistance exercise and the intake of essential amino acids (EAAs) are known to be factors that can affect muscle mass and strength improvement. The purpose of this study was to investigate changes in muscle quality, myokines, and inflammation in response to resistance exercise and EAA supplementation.

METHODS

Thirty-four males volunteered to participate in this study. They were assigned to four groups: (1) placebo (CO), (2) resistance exercise (RE), (3) EAA supplementation, and (4) RE + EAA supplementation. Body composition, muscle quality, myokines, and inflammation were measured at baseline and four weeks after treatment.

RESULTS

Lean body fat had decreased in both RE and RE + EAA groups. Lean body mass had increased in only the RE + EAA group. In all groups except for CO, irisin, myostatin A, and TNF-α levels had decreased. The grip strength of the right hand and trunk flexion peak torque increased in the RE group. The grip strength of the left hand, trunk flexion peak torque, and knee flexion peak torque of the left leg were increased in RE + EAA.

CONCLUSIONS

RE, EAA, and RE + EAA could effectively improve the muscle quality, myokine, and inflammation factors of young adult males. This finding highlights the importance of resistance exercise and amino acid intake.

Ingestion of a variety of non-animal-derived dietary protein sources results in diverse postprandial plasma amino acid responses which differ between young and older adults

Whole-body tissue protein turnover is regulated, in part, by the postprandial rise in plasma amino acid concentrations, although minimal data exist on the amino acid response following non-animal-derived protein consumption. We hypothesised that the ingestion of novel plant- and algae-derived dietary protein sources would elicit divergent plasma amino acid responses when compared with vegan- and animal-derived control proteins. Twelve healthy young (male (m)/female (f): 6/6; age: 22 ± 1 years) and 10 healthy older (m/f: 5/5; age: 69 ± 2 years) adults participated in a randomised, double-blind, cross-over trial. During each visit, volunteers consumed 30 g of protein from milk, mycoprotein, pea, lupin, spirulina or chlorella. Repeated arterialised venous blood samples were collected at baseline and over a 5-h postprandial period to assess circulating amino acid, glucose and insulin concentrations. Protein ingestion increased plasma total and essential amino acid concentrations (P < 0·001), to differing degrees between sources (P < 0·001), and the increase was further modulated by age (P < 0·001). Postprandial maximal plasma total and essential amino acid concentrations were highest for pea (2828 ± 106 and 1480 ± 51 µmol·l-1) and spirulina (2809 ± 99 and 1455 ± 49 µmol·l-1) and lowest for chlorella (2053 ± 83 and 983 ± 35 µmol·l-1) (P < 0·001), but were not affected by age (P > 0·05). Postprandial total and essential amino acid availabilities were highest for pea, spirulina and mycoprotein and lowest for chlorella (all P < 0·05), but no effect of age was observed (P > 0·05). The ingestion of a variety of novel non-animal-derived dietary protein sources elicits divergent plasma amino acid responses, which are further modulated by age.

Post-prandial muscle protein synthesis rates following the ingestion of pea-derived protein do not differ from ingesting an equivalent amount of milk-derived protein in healthy, young males

PURPOSE

Plant-derived proteins have received considerable attention as an alternative to animal-derived proteins. However, plant-derived proteins are considered to have less anabolic properties when compared with animal-derived proteins. The lower muscle protein synthesis rates following ingestion of plant- compared with animal-derived protein have been attributed to the lower essential amino acid content of plant-derived proteins and/or their specific amino acid deficiencies. This study aimed to compare post-prandial muscle protein synthesis rates following the ingestion of 30 g pea-derived protein with 30 g milk-derived protein in healthy, young males.

METHODS

In a randomized, double-blind, parallel-group design, 24 young males (24 ± 3 y) received a primed continuous L-[ring-13C6]-phenylalanine infusion after which they ingested 30 g pea (PEA) or 30 g milk-derived protein (MILK). Blood and muscle biopsies were collected frequently for 5 h to assess post-prandial plasma amino acid profiles and subsequent post-prandial muscle protein synthesis rates.

RESULTS

MILK increased plasma essential amino acid concentrations more than PEA over the 5 h post-prandial period (incremental area under curve 151 ± 31 vs 102 ± 15 mmol∙300 min∙L-1, respectively; P < 0.001). Ingestion of both MILK and PEA showed a robust muscle protein synthetic response with no significant differences between treatments (0.053 ± 0.013 and 0.053 ± 0.017%∙h-1, respectively; P = 0.96).

CONCLUSION

Post-prandial muscle protein synthesis rates following the ingestion of 30 g pea-derived protein do not differ from the response following ingestion of an equivalent amount of milk-derived protein. International Clinical Trials Registry Platform (NTR6548; 27-06-2017).

The association between different types of amino acid intake and physical growth among children

BACKGROUND & AIMS

Restricted linear growth and abnormal weight status are commonly observed among children in low-income countries, possibly due to inadequate protein intake. Considering the role of protein intake and amino acid (AA) synthesis in growth and development, it has been suggested that there may be an association between AA intake and physical growth. We aimed to investigate the association between different types of AA intake and physical growth among children.

METHODS

A cross-sectional study including 780 six-year-old children referred to 10 health care centers for vaccination between October 2017 and March 2018 was conducted. Anthropometric data was collected using standard methods, and dietary intake was assessed using a validated food-frequency questionnaire (FFQ)‏ in an interview by a trained technician.

RESULTS

Children in the highest tertile (3rd) of branched-chain amino acids (BCAA) intake had a higher weight-for-age z-score (WAZ) (P = 0.02) and body mass index-for-age z-score (BAZ) (P = 0.001) compared to those in the lowest tertile (1st). Interestingly, BAZ was significantly associated with the highest tertile of acidic AA intake (P = 0.04), while an inverse association was observed between the highest tertile of aromatic AA (phenylalanine and tyrosine) intake and BAZ (P = 0.01) . No significant associations were observed between the highest tertile of sulfuric, aliphatic, or neutral AA and BAZ, height-for-age z-score (HAZ) or WAZ. Further, underweight was associated with the 3rd tertile of aromatic, alcoholic, aliphatic or neutral AA and BCAA intake. Aliphatic and neutral AA intake was also increased the risk of overweight. Finally, stunted growth patterns were associated with the highest tertile of acidic, alcoholic.

CONCLUSION

Findings presented in this study showed that higher BAZ and WAZ are associated with 3rd tertiles of BCAA intake, but lower BAZ were associated with 3rd tertiles of aromatic AA (phenylalanine and tyrosine) intake. Future research in other populations are needed to confirm these findings.

Nutritional aspects of prehabilitation in adults with cirrhosis awaiting liver transplant

Malnutrition, sarcopenia (low muscle mass), and physical frailty have gained increasing recognition in candidates for liver transplant (LT) as these conditions can impact postoperative functional capacity. Multidimensional prehabilitation programs have been proposed as a safe intervention in adults awaiting LT but the nutritional pillar of prehabilitation has been understudied. This review summarizes the nutritional recommendations for prehabilitation for individuals with cirrhosis awaiting LT. Three major aspects of nutritional prehabilitation are discussed: (1) Assess: Evaluate nutritional status and assess for malnutrition, sarcopenia, and frailty to guide the nutritional prehabilitation intervention intensity, increasing across universal, targeted, and specialist levels; (2) Intervene: Prescribe a nutritional prehabilitation intervention to meet established nutrition guidelines in cirrhosis with a targeted focus on improving nutritional status and muscle health; (3) Reassess: Follow-up based on the required intensity of nutritional care with as needed intervention adjustment. Topics covered in the review include nutritional care levels for prehabilitation, energy prescriptions across body mass index strata, detailed considerations around protein intake (amount, distribution, and quality), carbohydrate and fat intake, other nutritional considerations, and the potential role of dietary supplements and nutraceuticals. Future research is warranted to more accurately evaluate energy needs, evaluate emerging dietary supplementation strategies, and establish the role of nutraceuticals alongside food-based interventions. While the general principles of nutritional prehabilitation are ready for immediate application, future large-scale randomized controlled trials in this space will help to quantify the benefit that can be gained by transitioning the LT approach from passive "transplant waitlist time" to active "transplant preparation time."

Acute ingestion of a ketone monoester, whey protein, or their co-ingestion in the overnight postabsorptive state elicit a similar stimulation of myofibrillar protein synthesis rates in young males: a double-blind randomized trial

BACKGROUND

Ketone bodies may have anabolic effects in skeletal muscle via their capacity to stimulate protein synthesis. Whether orally ingested exogenous ketones can stimulate postprandial myofibrillar protein synthesis (MyoPS) rates with and without dietary protein co-ingestion is unknown.

OBJECTIVES

This study aimed to evaluate the effects of ketone monoester intake and elevated blood β-hydroxybutyrate (β-OHB) concentration, with and without dietary protein co-ingestion, on postprandial MyoPS rates and mechanistic target of rapamycin complex 1 (mTORC1) pathway signaling.

METHODS

In a randomized, double-blind, parallel group design, 36 recreationally active healthy young males (age: 24.2 ± 4.1 y; body fat: 20.9% ± 5.8%; body mass index: 23.4 ± 2 kg/m2) received a primed continuous infusion of L-[ring-2H5]-phenylalanine and ingested one of the following: 1) the ketone monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (KET), 2) 10 g whey protein (PRO), or 3) the combination of both (KET+PRO). Blood and muscle biopsy samples were collected during basal and postprandial (300 min) conditions to assess β-OHB, glucose, insulin, and amino acid concentrations, MyoPS rates, and mTORC1 pathway signaling.

RESULTS

Capillary blood β-OHB concentration increased similarly during postprandial conditions in KET and KET+PRO, with both being greater than PRO from 30 to 180 min (treatment × time interaction: P < 0.001). Postprandial plasma leucine and essential amino acid (EAA) incremental area under the curve (iAUC) over 300 min was greater (treatment: both P < 0.001) in KET+PRO compared with PRO and KET. KET, PRO, and KET+PRO stimulated postprandial MyoPS rates (0-300 min) higher than basal conditions [absolute change: 0.020%/h; (95% CI: 0.013, 0.027%/h), 0.014%/h (95% CI: 0.009, 0.019%/h), 0.019%/h (95% CI: 0.014, 0.024%/h), respectively (time: P < 0.001)], with no difference between treatments (treatment: P = 0.383) or treatment × time interaction (interaction: P = 0.245). mTORC1 pathway signaling responses did not differ between treatments (all P > 0.05).

CONCLUSIONS

Acute oral intake of a ketone monoester, 10 g whey protein, or their co-ingestion in the overnight postabsorptive state elicit a similar stimulation of postprandial MyoPS rates in healthy young males. This trial was registered at clinicaltrials.gov as NCT04565444 (https://clinicaltrials.gov/study/NCT04565444).

Alterations in the diversity, composition and function of the gut microbiota in Uyghur individuals with sarcopenia

BACKGROUND

Research on the gut microbiota has emerged as a new direction for understanding pathophysiologic changes in diseases associated with aging, such as sarcopenia. Several studies have shown that there are differences in the gut microbiota between individuals with sarcopenia and without sarcopenia. However, these differences are not consistent across regions and ethnic groups, and additional research is needed.

METHODS

In this study, we collected fresh fecal samples from 31 Uyghur individuals with sarcopenia and 31 healthy controls. We used 16S rRNA sequencing to obtain fecal base sequences and analyzed the diversity, composition and function of the gut microbiota.

RESULTS

There was no significant difference in alpha diversity between the sarcopenia group and the healthy control group (P > 0.05). There was a significant difference in beta diversity between the groups (P < 0.05). In the sarcopenia group, the abundances of Alloprevotella, un_f_Prevotellaceae, Anaerovibrio, Prevotellaceae_NK3B31_group, Mitsuokella, Prevotella and Allisonella were lower than those in the heathy control group, and the abundances of Flavobacteriales, Flavobacteriaceae, Catenibacterium, Romboutsia, Erysipelotrichaceae_UCG-003, GCA-900066575, Lachnospiraceae_FCS020_group, and un_f_Flavobacteriaceae were higher than those in the heathy control group. Linear discriminant analysis effect size (LEfSe) revealed that the microbial species in the control group that were significantly different from those in the sarcopenia group were concentrated in the genus Alloprevotella, while the species in the sarcopenia group were concentrated in the genus Catenibacterium. Functional prediction analysis revealed that D-alanine, glycine, serine, and threonine metabolism and transcription machinery, among others, were enriched in the sarcopenia group, which indicated that metabolic pathways related to amino acid metabolism and nutrient transport may be regulated to varying degrees in the pathophysiological context of sarcopenia.

CONCLUSIONS

There were significant differences in the composition and function of the gut microbiota between Xinjiang Uyghur sarcopenia individuals and healthy individuals. These findings might aid in the development of probiotics or microbial-based therapies for sarcopenia in Uyhur individuals.

Protein digestibility and ACE inhibitory activity of fermented flours in older adults and standard gastrointestinal simulation

Consumption of essential amino acids responsible for muscle protein synthesis is important in preventing sarcopenia among older individuals. This population may experience gastrointestinal disorders that inhibit protein digestibility, making it crucial to address. Therefore, solid-state fermentation (SSF) using Pleurotus ostreatus and air drying has been suggested as a means of improving the protein digestibility of lentils and quinoa. SSF combined with air drying at 70 °C resulted in a slight increase in protein hydrolysis compared to unfermented samples. SSF was found to boost the proportion of small peptides to 35 %. Following digestion, SSF and drying yielded bioactive peptides of 1400 and 450 Da, with a range of 11 % to 28 %, respectively, and peptides < 190 Da making up 60 % of the total. SSF promoted valine, leucine, and isoleucine generation; however, hot air drying reduced free amino acids due to the amino acid-reducing sugar bonding but was never lower than the initial content of its unfermented counterpart. Furthermore, SSF and drying at 70 °C improved the release of hydrophobic amino acids (>70 mg/g dry basis) and negatively charged amino acids (>20 mg/g dry basis) in lentils during digestion. The SSF samples exhibited lower angiotensin converting enzyme (ACE) inhibitory activity, ≤35 %, compared to unfermented flours after digestion. However, the ACE inhibitory activity increased in SSF-dried samples, in part because of melanoidins generated during drying. Finally, lower values of protein digestibility and thus smaller peptides, amino acid profile, and ACE inhibitory activity of fermented flours were found in the older adult digestion model.

Effects of Whey Protein Combined with Amylopectin/Chromium on the Muscle Protein Synthesis and mTOR Phosphorylation in Exercised Rats

This study aimed to examine the impact of varying doses of whey protein (WP) and amylopectin/chromium complex (ACr) supplementation on muscle protein synthesis (MPS), amino acid and insulin levels, and the rapamycin (mTOR) signaling pathways in exercised rats. A total of 72 rats were randomly divided into nine groups: (1) Exercise (Ex), (2) Ex + WPI to (5) Ex + WPIV with various oral doses of whey protein (0.465, 1.55, 2.33, and 3.1 g/kg) and (6) Ex + WPI + ACr to (9) Ex + WPIV + ACr with various doses of whey protein combined with 0.155 g/kg ACr. On the day of single-dose administration, the products were given by oral gavage after exercise. To measure the protein fractional synthesis rate (FSR), a bolus dose of deuterium-labeled phenylalanine was given, and its effects were evaluated 1 h after supplementation. Rats that received 3.1 g/kg of whey protein (WP) combined with ACr exhibited the most significant increase in muscle protein synthesis (MPS) compared to the Ex group (115.7%, p < 0.0001). In comparison to rats that received the same dose of WP alone, those given the combination of WP and ACr at the same dosage showed a 14.3% increase in MPS (p < 0.0001). Furthermore, the WP (3.1 g/kg) + ACr group exhibited the highest elevation in serum insulin levels when compared to the Ex group (111.9%, p < 0.0001). Among the different groups, the WP (2.33 g/kg) + ACr group demonstrated the greatest increase in mTOR levels (224.2%, p < 0.0001). Additionally, the combination of WP (2.33 g/kg) and ACr resulted in a 169.8% increase in 4E-BP1 levels (p < 0.0001), while S6K1 levels rose by 141.2% in the WP (2.33 g/kg) + ACr group (p < 0.0001). Overall, supplementation with various doses of WP combined with ACr increased MPS and enhanced the mTOR signaling pathway compared to WP alone and the Ex group.

The muscle protein synthetic response following corn protein ingestion does not differ from milk protein in healthy, young adults

Plant-derived proteins are generally believed to possess lesser anabolic properties when compared with animal-derived proteins. This is, at least partly, attributed to the lower leucine content of most plant-derived proteins. Corn protein has a leucine content that is highest among most plant-derived proteins and it even exceeds the levels observed in animal-derived proteins such as whey protein. Therefore, this study aimed to compare muscle protein synthesis rates following the ingestion of 30 g corn protein and a 30 g blend of corn plus milk protein with 30 g milk protein. In a randomized, double blind, parallel-group design, 36 healthy young males (26 ± 4 y) received primed continuous L-[ring-13C6]-phenylalanine infusions and ingested 30 g corn protein (CORN), 30 g milk protein (MILK), or a 30 g proteinblend with 15 g corn plus 15 g milk protein (CORN + MILK). Blood and muscle biopsies were collected for 5 h following protein ingestion to assess post-prandial plasma amino acid profiles and myofibrillar protein synthesis rates. The results show that Ingestion of protein increased myofibrillar protein synthesis rates from basal post-absorptive values in all treatments(P < 0.001). Post-prandial myofibrillar protein synthesis rates did not differ between CORN vs MILK (0.053 ± 0.013 vs 0.053 ± 0.013%∙h-1, respectively; t-test P = 0.90), or between CORN + MILK vs MILK (0.052 ± 0.024 vs 0.053 ± 0.013%∙h-1, respectively; t-test P = 0.92). Ingestion of 30 g corn protein, 30 g milk protein, or a blend of 15 g corn plus 15 g milk protein robustly increases muscle protein synthesis rates in young males. The muscle protein synthetic response to the ingestion of 30 g corn-derived protein does not differ from the ingestion of an equivalent amount of milk protein in healthy, young males. Clinical Trial Registry number. NTR6548 (registration date: 27-06-2017) https://www.trialregister.nl/ .

Advancing nutrition risk assessment in middle-aged and older individuals with diverse food cultures: A data-driven personalized approach to predict incident hypertension, diabetes and mortality

BACKGROUND

Personalized nutrition risk assessment is crucial in addressing the association between healthy dietary habits across the life course and the development of disease, functional capacity, and healthy aging, as specific dietary pattern recommendations may not be suitable for diverse food cultures.

OBJECTIVE

To develop a data-driven, personalized nutrition risk assessment algorithm linked to incident hypertension, diabetes, and all-cause mortality utilizing the food frequency questionnaire among middle-aged and older individuals.

METHODS

A retrospective, population-based cohort study conducted between 1999 and 2015 utilized the nationally representative Taiwan Longitudinal Study on Aging (TLSA) survey to examine personalized dietary risk clusters and their associations with health outcomes. Latent class analysis was performed to derive the dietary diversity clusters among community-dwelling middle-aged and older individuals. Outcomes were defined as new-onset hypertension, diabetes mellitus and all-cause mortality at 4-, 8-, 12- and 16-year follow-ups.

RESULTS

Data from 1,811 participants (58.14% males, 43.90% aged 50-64 years) showed that around one-third of participants reported being illiterate, 21.98% widowed, and 51.46% engaging in regular physical exercise. Four dietary diversity clusters were identified: "least diverse", "fish and meat", "dairy, fruit, and vegetable", and "most diverse". The "most diverse" cluster was characterized by a high consumption of protein-rich foods, while the "dairy, fruit, and vegetable" cluster had the highest consumption of dairy products and beans/legumes. The "least diverse" cluster had the lowest intake of protein-rich foods, and dark-colored vegetables and fruits. The "most diverse" cluster had a significantly lower risk of hypertension development at the 4-year (aOR 0.58; p < 0.02) and 8-year (aOR 0.57; p < 0.01) follow-up and diabetes at the 4-year (aOR 0.44; p < 0.03) follow-up. Participants in the "most diverse" clusters exhibited lower risks of 8-year, 12-year, and 16-year mortality than those in the "least diverse" cluster (aOR 0.67, p < 0.05; 0.67, p < 0.03; and 0.50, p < 0.01, respectively).

CONCLUSION

The personalized nutrition risk assessment algorithm from the food frequency questionnaire can effectively stratify personal health risks among diverse middle-aged and older individuals, making it a valuable tool in lifestyle modification and intervention studies.

Interindividual- and blood-correlated sweat phenylalanine multimodal analytical biochips for tracking exercise metabolism

In situ monitoring of endogenous amino acid loss through sweat can provide physiological insights into health and metabolism. However, existing amino acid biosensors are unable to quantitatively assess metabolic status during exercise and are rarely used to establish blood-sweat correlations because they only detect a single concentration indicator and disregard sweat rate. Here, we present a wearable multimodal biochip integrated with advanced electrochemical electrodes and multipurpose microfluidic channels that enables simultaneous quantification of multiple sweat indicators, including phenylalanine and chloride, as well as sweat rate. This combined measurement approach reveals a negative correlation between sweat phenylalanine levels and sweat rates among individuals, which further enables identification of individuals at high metabolic risk. By tracking phenylalanine fluctuations induced by protein intake during exercise and normalizing the concentration indicator by sweat rates to reduce interindividual variability, we demonstrate a reliable method to correlate and analyze sweat-blood phenylalanine levels for personal health monitoring.

Oral histidine affects gut microbiota and MAIT cells improving glycemic control in type 2 diabetes patients

Amino acids, metabolized by host cells as well as commensal gut bacteria, have signaling effects on host metabolism. Oral supplementation of the essential amino acid histidine has been shown to exert metabolic benefits. To investigate whether dietary histidine aids glycemic control, we performed a case-controlled parallel clinical intervention study in participants with type 2 diabetes (T2D) and healthy controls. Participants received oral histidine for seven weeks. After 2 weeks of histidine supplementation, the microbiome was depleted by antibiotics to determine the microbial contribution to histidine metabolism. We assessed glycemic control, immunophenotyping of peripheral blood mononucelar cells (PBMC), DNA methylation of PBMCs and fecal gut microbiota composition. Histidine improves several markers of glycemic control, including postprandial glucose levels with a concordant increase in the proportion of MAIT cells after two weeks of histidine supplementation. The increase in MAIT cells was associated with changes in gut microbial pathways such as riboflavin biosynthesis and epigenetic changes in the amino acid transporter SLC7A5. Associations between the microbiome and MAIT cells were replicated in the MetaCardis cohort. We propose a conceptual framework for how oral histidine may affect MAIT cells via altered gut microbiota composition and SLC7A5 expression in MAIT cells directly and thereby influencing glycemic control. Future studies should focus on the role of flavin biosynthesis intermediates and SLC7A5 modulation in MAIT cells to modulate glycemic control.

Metabolites of the gut microbiota may serve as precise diagnostic markers for sarcopenia in the elderly

Sarcopenia, a disease recognized by the World Health Organization, has posed a great challenge to the world in the current aging society. The vital role of the gut microbiome through the gut-muscle axis in sarcopenia is increasingly recognized. However, the working mechanisms by which the gut microbiota functions have not been fully explored in the multi-omics field. Here, we designed a cross-sectional study that recruited patients (n = 32) with sarcopenia and healthy old adults (n = 31). Diagnosis of sarcopenia was based on the Asian Working Group for Sarcopenia (AWGS) in 2019 criteria. Muscle mass was represented by appendicular skeletal muscle mass measured by using direct segmental multi-frequency bioelectrical impedance and muscle strength was evaluated using the handgrip strength. The Short Physical Performance Battery, the 5-time Chair Stand Test, and the 4-metre Walk Test were used to assess physical performance. Shotgun metagenomic sequencing was used to profile the gut microbiome in order to identify its construction and function. Metabolome based on untargeted metabolomics was applied to describe the features and structure of fecal metabolites. In clinical indexes including triglycerides and high-density lipoprotein cholesterol, we noted a significant decrease in triglycerides (TG) and a significant increase in high-density lipoprotein cholesterol (HDL-C) in patients with sarcopenia. Appendicular skeletal muscle mass of patients with sarcopenia was lower than the health group. Based on intestinal metagenomic and fecal metabolomic profiles, we found that the gut microbiome and metabolome were disturbed in patients with sarcopenia, with significant decreases in bacteria such as Bifidobacterium longum, Bifidobacterium pseudocatenulatum, and Bifidobacterium adolescentis, as well as metabolites such as shikimic acid. Also, we plotted supervised classification models at the species level of gut bacteria (AUC = 70.83-88.33) and metabolites (AUC = 92.23-98.33) based on machine learning, respectively. Based on the gut-muscle axis network, a potential mechanism is proposed along the gut microbiome - key metabolites - clinical index, that Phascolarctobacterium faecium affects appendicular skeletal muscle mass, calf circumference, handgrip strength, and BMI via Shikimic acid metabolites. This study elucidates the potential mechanisms by which the gut microbiome influences the progress of sarcopenia through metabolites and provides a meaningful theoretical foundation for reference in the diagnosis and treatment of sarcopenia.

Combined Exercise Training and Nutritional Interventions or Pharmacological Treatments to Improve Exercise Capacity and Body Composition in Chronic Obstructive Pulmonary Disease: A Narrative Review

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease that is associated with significant morbidity, mortality, and healthcare costs. The burden of respiratory symptoms and airflow limitation can translate to reduced physical activity, in turn contributing to poor exercise capacity, muscle dysfunction, and body composition abnormalities. These extrapulmonary features of the disease are targeted during pulmonary rehabilitation, which provides patients with tailored therapies to improve the physical and emotional status. Patients with COPD can be divided into metabolic phenotypes, including cachectic, sarcopenic, normal weight, obese, and sarcopenic with hidden obesity. To date, there have been many studies performed investigating the individual effects of exercise training programs as well as nutritional and pharmacological treatments to improve exercise capacity and body composition in patients with COPD. However, little research is available investigating the combined effect of exercise training with nutritional or pharmacological treatments on these outcomes. Therefore, this review focuses on exploring the potential additional beneficial effects of combinations of exercise training and nutritional or pharmacological treatments to target exercise capacity and body composition in patients with COPD with different metabolic phenotypes.

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.

Algae Ingestion Increases Resting and Exercised Myofibrillar Protein Synthesis Rates to a Similar Extent as Mycoprotein in Young Adults

BACKGROUND

Spirulina [SPIR] (cyanobacterium) and chlorella [CHLO] (microalgae) are foods rich in protein and essential amino acids; however, their capacity to stimulate myofibrillar protein synthesis (MyoPS) in humans remains unknown.

OBJECTIVES

We assessed the impact of ingesting SPIR and CHLO compared with an established high-quality nonanimal-derived dietary protein source (fungal-derived mycoprotein [MYCO]) on plasma amino acid concentrations, as well as resting and postexercise MyoPS rates in young adults.

METHODS

Thirty-six healthy young adults (age: 22 ± 3 y; BMI: 23 ± 3 kg·m-2; male [m]/female [f], 18/18) participated in a randomized, double-blind, parallel-group trial. Participants received a primed, continuous infusion of L-[ring-2H5]-phenylalanine and completed a bout of unilateral-resistance leg exercise before ingesting a drink containing 25 g protein from MYCO (n = 12; m/f, 6/6), SPIR (n = 12; m/f, 6/6), or CHLO (n = 12; m/f, 6/6). Blood and bilateral muscle samples were collected at baseline and during a 4-h postprandial and postexercise period to assess the plasma amino acid concentrations and MyoPS rates in rested and exercised tissue.

RESULTS

Protein ingestion increased the plasma total and essential amino acid concentrations (time effects; all P < 0.001), but most rapidly and with higher peak responses following the ingestion of SPIR compared with MYCO and CHLO (P < 0.05), and MYCO compared with CHLO (P < 0.05). Protein ingestion increased MyoPS rates (time effect; P < 0.001) in both rested (MYCO, from 0.041 ± 0.032 to 0.060 ± 0.015%·h-1; SPIR, from 0.042 ± 0.030 to 0.066 ± 0.022%·h-1; and CHLO, from 0.037 ± 0.007 to 0.055 ± 0.019%·h-1, respectively) and exercised tissue (MYCO, from 0.046 ± 0.014 to 0.092 ± 0.024%·h-1; SPIR, from 0.038 ± 0.011 to 0.086 ± 0.028%·h-1; and CHLO, from 0.048 ± 0.019 to 0.090 ± 0.024%·h-1, respectively), with no differences between groups (interaction effect; P > 0.05), but with higher rates in exercised compared with rested muscle (time × exercise effect; P < 0.001).

CONCLUSIONS

The ingestion of a single bolus of algae-derived SPIR and CHLO increases resting and postexercise MyoPS rates to a comparable extent as MYCO, despite divergent postprandial plasma amino acid responses.

Publication trends in nutrition research for sarcopenic obesity: A 20-year bibliometric analysis

BACKGROUND

We used bibliometric methods to evaluate publications on the role of nutrition in sarcopenic obesity and analyzed the current situation and developmental trends over the past 2 decades.

METHODS

Publications from 2002 to 2022 related to the role of nutrition in sarcopenic obesity were extracted from the Web of Science Core Collection database. CiteSpace, VOSviewer, and the Bibliometrix R package were applied to build relevant network diagrams.

RESULTS

One thousand ninety-four articles from 64 countries were included. The annual number of publications in this field has shown an intense growth trend. The University of Alberta, Yonsei University, and Korea University are the major research institutions. Clinical Nutrition has published the most papers on the role of nutrition in sarcopenic obesity, and the American Journal of Clinical Nutrition is the most co-cited journal. A total of 5834 authors conducted the relevant studies. Yves Boirie has published the most papers in this field, and AJ Cruz-Jentoft is the most co-cited author.

CONCLUSION

This is the first bibliometric study of the role of nutrition in sarcopenic obesity. This study systematically summarizes the research hotspots and development directions in this field, and provides a reference for scholars studying the role of nutrition in sarcopenic obesity.

Common Beans as a Source of Amino Acids and Cofactors for Collagen Biosynthesis

Common beans (Phaseolus vulgaris L.) are widely consumed in diets all over the world and have a significant impact on human health. Proteins, vitamins, minerals, phytochemicals, and other micro- and macronutrients are abundant in these legumes. On the other hand, collagens, the most important constituent of extracellular matrices, account for approximately 25-30 percent of the overall total protein composition within the human body. Hence, the presence of amino acids and other dietary components, including glycine, proline, and lysine, which are constituents of the primary structure of the protein, is required for collagen formation. In this particular context, protein quality is associated with the availability of macronutrients such as the essential amino acid lysine, which can be acquired from meals containing beans. Lysine plays a critical role in the process of post-translational modifications facilitated with enzymes lysyl hydroxylase and lysyl oxidase, which are directly involved in the synthesis and maturation of collagens. Furthermore, collagen biogenesis is influenced by the cellular redox state, which includes important minerals and bioactive chemicals such as iron, copper, and certain quinone cofactors. This study provides a novel perspective on the significant macro- and micronutrients present in Phaseolus vulgaris L., as well as explores the potential application of amino acids and cofactors derived from this legume in the production of collagens and bioavailability. The utilization of macro- and micronutrients obtained from Phaseolus vulgaris L. as a protein source, minerals, and natural bioactive compounds could optimize the capacity to promote the development and durability of collagen macromolecules within the human body.