Dietary Protein Quantity, Quality, and Exercise Are Key to Healthy Living: A Muscle-Centric Perspective Across the Lifespan

High-Moisture Extrusion of a Dietary Protein Blend Impairs In Vitro Digestion and Delays In Vivo Postprandial Plasma Amino Acid Availability in Humans

BACKGROUND

Industrial processing can alter the structural complexity of dietary proteins and, potentially, their digestion and absorption upon ingestion. High-moisture extrusion (HME), a common processing method used to produce meat alternative products, affects in vitro digestion, but human data are lacking. We hypothesized that HME of a mycoprotein/pea protein blend would impair in vitro digestion and in vivo postprandial plasma amino acid availability.

METHODS

In Study A, 9 healthy volunteers completed 2 experimental trials in a randomized, double-blind, crossover design. Participants consumed a beverage containing 25 g protein from a "dry" blend (CON) of mycoprotein/pea protein (39%/61%) or an HME content-matched blend (EXT). Arterialized venous blood samples were collected in the postabsorptive state and regularly over a 5-h postprandial period to assess plasma amino acid concentrations. In Study B, in vitro digestibility of the 2 beverages were assessed using bicinchoninic acid assay and optical fluorescence microscopy at baseline and during and following gastric and intestinal digestion using the INFOGEST model of digestion.

RESULTS

Protein ingestion increased plasma total, essential (EAA), and branched-chain amino acid (BCAA) concentrations (time effect, P < 0.0001) but more rapidly and to a greater magnitude in the CON compared with the EXT condition (condition × time interaction, P < 0.0001). This resulted in greater plasma availability of EAA and BCAA concentrations during the early postprandial period (0-150 min). These data were corroborated by the in vitro approach, which showed greater protein availability in the CON (2150 ± 129 mg/mL) compared with the EXT (590 ± 41 mg/mL) condition during the gastric phase. Fluorescence microscopy revealed clear structural differences between the 2 conditions.

CONCLUSIONS

These data demonstrate that HME delays in vivo plasma amino acid availability following ingestion of a mycoprotein/pea protein blend. This is likely due to impaired gastric phase digestion as a result of HME-induced aggregate formation in the pea protein. This trial was registered at clinicaltrials.gov as NCT05584358.

Postprandial plasma amino acid and appetite responses with ingestion of a novel salmon-derived protein peptide in healthy young adults

This study assessed postprandial plasma aminoacidemia, glycemia, insulinemia and appetite responses to ingestion of a novel salmon-derived protein peptide (Salmon PP) compared with milk protein isolate (Milk PI). In a randomised, participant-blind crossover design, eleven healthy adults (M = 5, F = 6; mean ± sd age: 22 ± 3 years; BMI: 24 ± 3 kg/m2) ingested 0·3 g/kg/body mass of Salmon PP or Milk PI. Arterialised blood samples were collected whilst fasted and over a 240-min postprandial period. Appetite sensations were measured via visual analogue scales. An ad libitum buffet-style test meal was administered after each trial. The incremental AUC (iAUC) plasma essential amino acid (EAA) response was similar between Salmon PP and Milk PI. The iAUC plasma leucine response was significantly greater following Milk PI ingestion (P < 0·001), whereas temporal and iAUC plasma total amino acid (P = 0·001), non-essential amino acid (P = 0·002), glycine (P = 0·0025) and hydroxyproline (P < 0·001) responses were greater following Salmon PP ingestion. Plasma insulin increased similarly above post-absorptive values following Salmon PP and Milk PI ingestion, whilst plasma glucose was largely unaltered. Indices of appetite were similarly altered following Salmon PP and Milk PI ingestion, and total energy and macronutrient intake during the ad libitum meal was similar between Salmon PP and Milk PI. The postprandial plasma EAA, glycine, proline and hydroxyproline response to Salmon PP ingestion suggest this novel protein source could support muscle and possibly connective tissue adaptive remodelling, which warrants further investigation, particularly as the plasma leucine response to Salmon PP ingestion was inferior to Milk PI.

Dietary Habits and Race Day Strategies among Flexitarian, Vegetarian, and Vegan Recreational Endurance Runners: A Cross-Sectional Investigation from The NURMI Study (Step 2)

Many of today's recreational runners have changed their diet from omnivorous to vegetarian or vegan for reasons like better sport performance, animal ethics, positive health, eco-aspects, or male infertility. Others have constructed the flexitarian diet due to current trends in sustainable eating. The aim of this investigation was to analyze the dietary habits and race day strategies of recreational endurance runners following current sustainable dietary trends. Recreational endurance runners (18+ years) were invited to complete the standardized online survey on socio-demography/anthropometry, motivations, running/racing history, food frequency, and race day dietary strategy. Chi-squared tests and Wilcoxon tests were used for the statistical analysis. In total, 289 participants submitted the survey; 146 subjects following flexitarian (n = 34), vegetarian (n = 50), or vegan (n = 62) diets were included in the final sample. Significant differences were found across the diet types: BMI (p = 0.018), fruit/vegetable consumption (p < 0.001), and the dietary motive of performance (p = 0.045). The findings suggest that the flexitarian diet may be appropriate for health- and environmentally conscious populations living in a meat-centered society and lacking social support to eat completely vegetarian/vegan. Following a plant-based diet is perceived as easy for health-conscious, athletic populations, and the vegan diet does not require a particularly effortful/complex race day strategy for endurance runners.

Completely Plant-Based Diets That Meet Energy Requirements for Resistance Training Can Supply Enough Protein and Leucine to Maximize Hypertrophy and Strength in Male Bodybuilders: A Modeling Study

Despite increasing awareness of plant-based diets for health and athletic performance, athletes are cautioned that careful dietary monitoring is necessary. Whether commonly consumed plant-based diets are nutritionally adequate for maximal muscular hypertrophy remains unknown. This modeling study assessed the nutrient composition of completely plant-based diets scaled to the caloric demands of maximal muscle mass and strength development in adult male bodybuilders. To model calorie requirements, anthropometric data from bodybuilders were input into the Tinsley resting metabolic rate prediction equation, and an appropriate physical activity factor and calorie surplus were applied. Dietary data from a large cohort following completely plant-based diets were then scaled to meet these needs. Modeled intakes for nutrients of interest were calculated as 1.8 g/kg/day of protein and 2.75 g/meal of leucine, which surpass mean requirements for maximal increases in muscle mass and strength and muscle protein synthesis, respectively. Daily levels for all micronutrients, except vitamin D, also exceeded requirements. Saturated fat levels were aligned with dietary guidelines, although sodium levels exceeded recommended limits. Consumption of larger portions of commonplace plant-based diets, scaled to meet the energy demands of maximal accrual of muscle mass and strength, satisfied protein and leucine requirements without the need for additional planning.

The Importance of Dietary Protein Quality in Mid- to High-Income Countries

In wealthy countries, the protein intake of adults is usually considered to be adequate, and considerations of protein quality are often deemed irrelevant. The objective was to examine dietary protein intakes of adults in developed countries in the context of dietary protein quality. An analysis of NHANES population data on actual protein intakes in the United States (a developed country) demonstrated that for a dietary Digestible Indispensable Amino Acid Score (DIAAS) of 100%, 11% of the adult (19-50 y) population had habitual protein intakes below the Estimated Average Requirement (EAR) and 22% below the Recommended Dietary Allowance. The percentage of the population with utilizable protein intakes potentially falling below the EAR increased as the assumed DIAAS declined. Analysis of the NHANES data and several other datasets also indicated that total protein intakes can be limiting or close to limiting for the elderly and some vegetarians and vegans. Here, lower dietary protein quality can potentially lead to inadequate utilizable protein intakes. For many people in specific physiological states (e.g., weight loss, endurance sports, resistance exercise) attempting to meet higher dietary protein targets often with accompanying lowered energy intakes, low dietary protein quality can lead to protein calories expressed as a proportion of total calories, falling outside what may be acceptable limits (maximum of 30% protein calories from total calories). In general, individuals within the adult population may be susceptible to macronutrient imbalance (whenever total protein intakes are high, daily energy intakes low) and for diets with lower protein quality (DIAAS <100%). Our analysis shows that dietary protein quality is relevant in mid- to high-income countries.

Prevalence of sarcopenia and its association with diet and physical activity in older adults with type 2 diabetes: A cross-sectional study

This cross-sectional study explored the prevalence of sarcopenia in older adults with type 2 diabetes and investigated the effects of diet and physical activity on sarcopenia. In total, 577 older adults with diabetes were recruited from a teaching hospital in Taiwan. Diet and physical activity were assessed using self-rated questionnaires, including the Healthy Diet Inventory, the Mini Nutritional Assessment-Short Form, and the International Physical Activity Questionnaire-Short Form. Sarcopenia was defined in accordance with the Asian Working Group for Sarcopenia 2019 guidelines. In total, 51.12% of participants had either possible sarcopenia, sarcopenia, or severe sarcopenia. Participants who were female, old age, prolonged sedentary times, poor nutritional status, and lower level of moderate-to-vigorous physical activity were identified as risk factors for possible to severe sarcopenia. Older adults with diabetes and possible to severe sarcopenia had poor nutrition status and engaged in inadequate physical activity. The findings indicate that sarcopenia may be related to nutrition status and physical activity, especially in older adults with diabetes.

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

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

The Influence of the Lactation Period and the Type of Milk on the Content of Amino Acids and Minerals in Human Milk and Infant Formulas

(1) Background: This study investigated the effect of the lactation period and the type of infant formula on the content of amino acids and selected minerals in an infant's food; (2) Methods: The study material consisted of breast milk (colostrum, n = 38; transitional milk, mature milk, n = 38) and three types of infant formulas (for first and follow-on feeding). Amino acid content was determined using an automatic amino acid analyzer, while minerals were determined by the atomic absorption spectrometry (AAS) technique; (3) Results: Breast milk and infant formulas contained a full range of essential amino acids. In most cases, the content of individual amino acids and minerals decreased with increasing lactation. In infant formulas, there were higher contents of phenylalanine, glutamic acid, proline, serine, and tyrosine in follow-on milk (p < 0.05). The EAA/TAA ratio in breast milk and infant formulas was similar, but the milk differed in their qualitative composition. Infant formulas contained levels of individual minerals that were several times higher-especially Mg, Ca, Mn, and Fe.; (4) Conclusions: Colostrum is more concentrated, and the level of amino acids and minerals is higher in it; as the milk matures, it decreases. In most cases, the content of individual amino acids and minerals is higher in infant formulas than in human milk, which is established through strict Codex Alimentarius procedures to ensure the proper development of infants.

Association of Macronutrients Intake with Body Composition and Sarcopenic Obesity in Children and Adolescents: A Population-Based Analysis of the National Health and Nutrition Examination Survey (NHANES) 2011-2018

The association of macronutrients intake with body composition and sarcopenic obesity remains uncertain in children and adolescents. We aimed to explore the association between macronutrients intake and body composition, especially sarcopenic obesity, in children and adolescents residing in the United States. The study utilized data from 5412 participants aged 6-17 years who attended NHANES between 2011 and 2018. Body composition was assessed using DXA, and nutrient intake was based on 24-h recall. Multivariable linear regression and multinomial logistic regression were used. The unweighted prevalence of sarcopenic obesity was 15.6%. A higher percentage of energy (5 %E) from fat was inversely associated with muscle mass but positively associated with fat mass and sarcopenic obesity. Substituting carbohydrate (5 %E) with fat decreased muscle mass by 0.03 (95% CI 0.01 to 0.06) but increased fat mass by 0.03 (95% CI 0.01 to 0.06) and increased the prevalence of sarcopenic obesity by 254% (95% CI 15% to 487%). Replacing protein intake with fat intake also increased the OR of sarcopenic obesity (OR, 2.36 [95% CI 1.18 to 3.18]). In conclusion, a high-fat diet, coupled with low carbohydrate/protein intake, is associated with sarcopenic obesity among children and adolescents. The change in children's diet towards a healthy diet with low fat composition may help prevent sarcopenic obesity. However, randomized clinical trials or longitudinal studies are needed to further validate our findings.

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

BACKGROUND

Protein is most commonly consumed as whole foods as opposed to single nutrients. However, the food matrix regulation of the postprandial muscle protein synthetic response has received little attention.

OBJECTIVES

The purpose of this study was to assess the effects of eating salmon (SAL) and of ingesting the same nutrients as an isolated mixture of crystalline amino acids and fish oil (ISO) on the stimulation of postexercise myofibrillar protein synthesis (MPS) and whole-body leucine oxidation rates in healthy young adults.

METHODS

Ten recreationally active adults (24 ± 4 y; 5 men, 5 women) performed an acute bout of resistance exercise, followed by the ingestion of SAL or ISO in a crossover fashion. Blood, breath, and muscle biopsies were collected at rest and after exercise during primed continuous infusions of L-[ring-2H5]phenylalanine and L-[1-13C]leucine. All data are presented as means ± SD and/or mean differences (95% CIs).

RESULTS

Postprandial essential amino acid (EAA) concentrations peaked earlier (P = 0.024) in the ISO group than those in the SAL group. Postprandial leucine oxidation rates increased over time (P < 0.001) and peaked earlier in the ISO group (1.239 ± 0.321 nmol/kg/min; 63 ± 25 min) than those in the SAL group (1.230 ± 0.561 nmol/kg/min; 105 ± 20 min; P = 0.003). MPS rates for SAL (0.056 ± 0.022 %/h; P = 0.001) and ISO (0.046 ± 0.025 %/h; P = 0.025) were greater than the basal rates (0.020 ± 0.011 %/h) during the 0- to 5-h recovery period, with no differences between conditions (P = 0.308).

CONCLUSION

We showed that the postexercise ingestion of SAL or ISO stimulate postexercise MPS rates with no differences between the conditions. Thus, our results indicate that ingesting protein from SAL as a whole-food matrix is similarly anabolic to ISO in healthy young adults. This trial was registered at www.

CLINICALTRIALS

gov as NCT03870165.

Optimal Protein Intake in Healthy Children and Adolescents: Evaluating Current Evidence

High protein intake might elicit beneficial or detrimental effects, depending on life stages and populations. While high protein intake in elder individuals can promote beneficial health effects, elevated protein intakes in infancy are discouraged, since they have been associated with obesity risks later in life. However, in children and adolescents (4–18 years), there is a scarcity of data assessing the effects of high protein intake later in life, despite protein intake being usually two- to three-fold higher than the recommendations in developed countries. This narrative review aimed to revise the available evidence on the long-term effects of protein intake in children and adolescents aged 4–18 years. Additionally, it discusses emerging techniques to assess protein metabolism in children, which suggest a need to reevaluate current recommendations. While the optimal range is yet to be firmly established, available evidence suggests a link between high protein intake and increased Body Mass Index (BMI), which might be driven by an increase in Fat-Free Mass Index (FFMI), as opposed to Fat Mass Index (FMI).

The association between meat consumption and muscle strength index in young adults: the mediating role of total protein intake and lean mass percentage

PURPOSE

The aim of this study was to analyse the associations between the consumption of different types of meat and the muscle strength index (MSI) and to examine whether this relationship is mediated by total protein intake (TPI) and lean mass percentage (LM%) in young adults.

METHODS

We conducted a cross-sectional study with first-year university students from Castilla-La Mancha, Spain. Different types of meat consumption (total, red, processed, and white and fish) were separately evaluated using a Food-Frequency Questionnaire. MSI was determined from the handgrip and standing long jump tests. ANCOVA models were used to test the mean differences in MSI by categories of meat consumption. Serial multiple mediation models were used to explore the mediating role of TPI and LM% in the relationship between meat consumption and MSI. All analyses were adjusted for age, sex, and socioeconomic level, identified through a directed acyclic graph. Additional analyses were performed with a small subsample including alcohol intake, tobacco smoking, physical activity, cardiorespiratory fitness, and total energy intake as covariates in the multiple mediation models.

RESULTS

A total of 230 students (mean age 21.1 ± 2.1 years, 66.5% women) were included in the analysis. Young adults with higher meat consumption (total, red, and white and fish) had higher MSI adjusted means than their peers with lower meat consumption (p < 0.05). These associations did not remain after controlling for TPI and LM%. In adjusted mediation analyses, a significant indirect effect was observed through TPI and LM% in the associations between each of the types of meat consumption and MSI. In the additional analyses, a greater effect of white and fish meat consumption on muscle strength through mediation of TPI and LM% was reported compared to red or processed meat consumption, and no significant effects were observed between processed meat consumption and MSI.

CONCLUSION

Higher consumption of total, red, and white and fish meat was associated with increased MSI in young adults. TPI and LM% mediated this relationship.

C-reactive protein, but not neutrophil-lymphocyte ratio, is inversely associated with muscle strength only in older men: NHANES 1999-2002

To evaluate the association of inflammation (C-reactive protein (CRP) and neutrophil-lymphocyte ratio (NLR) levels) with muscle strength in older adults. We also aimed to evaluate whether these associations are sex-specific. A cross-sectional study was performed with data from the National Health and Nutrition Examination Survey (NHANES) 1999-2000 and 2001-2002. A total of 2387 individuals over 50 years of both sexes were evaluated, according to the eligibility criteria for the strength test. Muscle strength was measured by Kinetic Communicator isokinetic dynamometer; while the NLR was obtained by the ratio of the total neutrophil for lymphocyte count and CRP was quantified by latex nephelometry. Linear regression analyses, crude and adjusted for confounders, were used to estimate the coefficients and 95 % confidence intervals for peak strength (muscle strength) by tertiles of NLR and CRP. There was no association between NLR and peak strength for both sexes. CRP levels were inversely associated with peak force in men [2nd tertile β = -3.33 (-15.92; 9.25); 3rd tertile β = -24.69 (-41.18; -8.20), p for trend = 0.005], but not in women [2nd tertile β = -3.22 (-15.00; 8.56); 3rd tertile β = -9.23 (-28.40; -9.94), p for trend = 0.332]. In conclusion, NLR levels were not associated with muscle strength in both sexes. CRP levels were inversely associated with muscle strength in older men, but not in women, suggesting that the association between inflammation and muscle strength in older adults can be sex-specific.

Food Waste Utilization for Reducing Carbon Footprints towards Sustainable and Cleaner Environment: A Review

There is world-wide generation of food waste daily in significant amounts, leading to depletion of natural resources and deteriorating air quality. One-third of global food produced is wasted laterally with the food value chain. Carbon footprint is an efficient way of communicating the issues related to climate change and the necessity of changing behavior. Valorization or utilization of food wastes helps in resolving issues related to environment pollution. Reduction in the carbon footprint throughout the chain of food supply makes the whole process eco-friendly. Prevailing food waste disposal systems focus on their economic and environmental viability and are putting efforts into using food waste as a resource input to agriculture. Effective and advanced waste management systems are adopted to deal with massive waste production so as to fill the gap between the production and management of waste disposal. Food waste biorefineries are a sustainable, eco-friendly, and cost-effective approach for the production of platform chemicals, biofuels, and other bio-based materials. These materials not only provide sustainable resources for producing various chemicals and materials but have the potential to reduce this huge environmental burden significantly. In this regard, technological advancement has occurred in past few years that has proven suitable for tackling this problem.

Recognizing the importance of protein quality in an era of food systems transformation

A transformation of current food systems is needed to nourish the growing global population in more sustainable ways. To support this, some are advocating for a shift to plant-based or -exclusive diets. These recommendations – typically borne out of concerns for the environment – often fail to account for unintended nutritional consequences, which could be particularly pronounced for protein intake. While there is enough protein to meet current global needs, the issue of protein quality is often overlooked and oversimplified. High-quality protein, including from animal source foods (ASF), is needed to meet nutritional demands in low- and middle-income countries (LMIC), particularly among vulnerable population groups. In high-income countries (HIC), protein quality is important for at-risk populations who have higher protein requirements and lower energy and/or protein intakes. Further, as the global population increases, driven primarily by population growth in LMIC, it is possible that protein production will need to increase in HIC to support exports to help feed the global population. The global dialogue and resulting dietary recommendations must therefore become more nuanced to consider the interaction between nutritional value and environmental impact to help better reflect trade-offs across multiple domains of sustainability. Nutritional life cycle assessments are one way to help accomplish this nuance and evaluate how all types of food production systems should be refocused to improve their environmental efficiency and nutritional impact.

Acetylcholinesterase and butyrylcholinesterase inhibitory activities of antioxidant peptides obtained from enzymatic pea protein hydrolysates and their ultrafiltration peptide fractions

This study optimized the enzymatic hydrolysis of yellow field pea proteins using alcalase (ACH), chymotrypsin (CHH), flavourzyme (FZH), pancreatin (PCH), pepsin (PEH), and trypsin (TPH) to obtain hydrolysates and ultrafiltered fractions (<1, 1-3, 3-5 and 5-10 kDa) that possess antioxidant plus acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities. The hydrolysates exhibited varying degrees of radical scavenging and inhibition of linoleic acid peroxidation, as well as cholinesterase inhibition activities but the potency generally improved by >10% after UF separation into peptide fractions. ACH, FZH, and PEH exhibited significantly (p < .05) higher (20%-30% increases) radical scavenging activities than the other hydrolysates. The 1 and 3 kDa UF fractions of ACH, FZH, and PEH inhibited ~20%-30% AChE activity, while ACH, PCH, TPH, and PEH inhibited ~20%-40% BuChE activity. We conclude that the pea protein hydrolysates and their peptide fractions possess multifunctional properties with potential use against neurodegenerative disorders. PRACTICAL APPLICATIONS: Alzheimer's disease (AD) has multiple pathological pathways in addition to the loss of acetylcholine (ACh) catalyzed by acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The presence of severe oxidative stress triggered by lipid peroxidation and formation of free radicals is a common trait in AD patients. The concept of AChE and BuChE inhibition as an approach toward AD amelioration involves the use of compounds with a similar structure to ACh, the natural substrate. Peptides derived from food proteins consist of ester bonds with structural similarity to ACh and theoretically possess the ability to interact with AChE and BuChE. Results from the present study imply that pea protein-derived peptides are potential candidates for use as inhibitors of AChE and BuChE activities, with application in the prevention and management of AD.

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

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

Perspective: Vegan Diets for Older Adults? A Perspective On the Potential Impact On Muscle Mass and Strength

Consumers are increasingly encouraged to consume more plant-based foods and lower their consumption of foods from animal origin. Concurrently, older adults are recommended to consume an adequate amount of high-quality dietary protein for the prevention of age-related muscle loss. In the current Perspective article, we discuss why it may not be preferred to consume a vegan diet at an older age. Our perspective is based on the proposed lower bioavailability and functionality of proteins in a vegan diet due to the matrix of the whole-food protein sources, the lower essential amino acid (EAA) content, and specific EAA deficiencies in proteins derived from plant-based foods. We propose that a vegan diet increases the risk of an inadequate protein intake at an older age and that current strategies to improve the anabolic properties of plant-based foods are not feasible for many older adults. We provide recommendations for further research to substantiate the remaining knowledge gaps regarding the consequences of a vegan diet on skeletal muscle mass and strength at an older age.

Handgrip strength and associated factors among Brazilian adolescents: A cross-sectional study

BACKGROUND

The handgrip strength (HGS) is an indicator of muscle strength associated with several health outcomes in adolescents and adults. This cross-sectional study aimed to identify HGS levels and associated modifiable and non-modifiable risk factors in adolescents.

METHODS

The study included 971 adolescents (496 boys) aged 15-18 years. The HGS was measured by a dynamometer, and the maximum value of right and left hands were summed for a total score. Age, economic status, balanced diet, physical activity, and sedentary behavior were assessed by questionnaires, while body mass index was determined by measuring body weight and height. Multiple linear regression was carried out to examine the association.

RESULTS

65.4% of the adolescents presented low levels of HGS (boys: 73.8%; girls: 56.6%). Low levels of HGS were associated with weight status and height in both sexes. In boys, low levels of HGS were associated with age, balanced diet, physical activity, and sedentary behavior.

CONCLUSION

About six out of ten adolescentes presented low levels of HGS. The main predictors of low levels of HGS in boys were age, physical activity, sedentary behavior, and balanced diet, and weight status and height in both sexes.

Physiological Limitations of Protein Foods Ounce Equivalents and the Underappreciated Role of Essential Amino Acid Density in Healthy Dietary Patterns

Protein quality is an important component of protein intake to support growth, development, and maintenance of essential body tissues and functions. Therefore, protein quality should be emphasized as a key characteristic during protein food selection within the larger context of healthy dietary patterns, especially when considering the wide variance of protein quality across animal- and plant-based foods. However, the USDA Dietary Guidelines for Americans (DGA) do not address specific protein quality recommendations within their protein foods ounce equivalents guidance or as a component of Healthy U.S. Style, Healthy Vegetarian, and Healthy Mediterranean Style dietary patterns. In addition, the protein foods ounce equivalents within the DGA are not established on any obvious metabolic equivalency characteristic [i.e., energy, protein, or essential amino acid (EAA) content], which creates misleading messaging of equivalent functional and metabolic benefit across protein foods. EAA content is a key characteristic of protein quality and can be a practical focal point for protein intake recommendations and achieving healthy dietary patterns. This review discusses the importance of protein quality, the state of messaging within DGA recommendations, and proposes EAA density (i.e., EAA content relative to total energy) as one practical approach to improve current dietary recommendations. Two recent publications that evaluated the DGA protein foods ounce equivalents based on metabolic effect and their application within DGA recommended dietary patterns are discussed.

Dietary protein requirements and recommendations for healthy older adults: a critical narrative review of the scientific evidence

Adequate protein intake is essential for the maintenance of whole-body protein mass. Different methodological approaches are used to substantiate the evidence for the current protein recommendations, and it is continuously debated whether older adults require more protein to counteract the age-dependent loss of muscle mass, sarcopenia. Thus, the purpose of this critical narrative review is to outline and discuss differences in the approaches and methodologies assessing the protein requirements and, hence, resulting in controversies in current protein recommendations for healthy older adults. Through a literature search, this narrative review first summarises the historical development of the Food and Agriculture Organization/World Health Organization/United Nations University setting of protein requirements and recommendations for healthy older adults. Hereafter, we describe the various types of studies (epidemiological studies and protein turnover kinetic measurements) and applied methodological approaches founding the basis and the different recommendations with focus on healthy older adults. Finally, we discuss important factors to be considered in future studies to obtain evidence for international agreement on protein requirements and recommendations for healthy older adults. We conclude by proposing future directions to determine 'true' protein requirements and recommendations for healthy older adults.

Histological and biochemical evaluation of skeletal muscle in the two salmonid species Coregonus maraena and Oncorhynchus mykiss

The growth of fishes and their metabolism is highly variable in fish species and is an indicator for fish fitness. Therefore, somatic growth, as a main biological process, is ecologically and economically significant. The growth differences of two closely related salmonids, rainbow trout (Oncorhynchus mykiss) and maraena whitefsh (Coregonus maraena), have not been adequately studied as a comparative study and are therefore insufficiently understood. For this reason, our aim was to examine muscle growth in more detail and provide a first complex insight into the growth and muscle metabolism of these two fish species at slaughter size. In addition to skeletal muscle composition (including nuclear counting and staining of stem and progenitor cells), biochemical characteristics, and enzyme activity (creatine kinase, lactate dehydrogenase, isocitrate dehydrogenase) of rainbow trout and maraena whitefish were determined. Our results indicate that red muscle contains cells with a smaller diameter compared to white muscle and those fibres had more stem and progenitor cells as a proportion of total nuclei. Interestingly, numerous interspecies differences were identified; in rainbow trout muscle RNA content, intermediate fibres and fibre diameter and in whitefish red muscle cross-sectional area, creatine kinase activity were higher compared to the other species at slaughter weight. The proportional reduction in red muscle area, accompanied by an increase in DNA content and a lower activity of creatine kinase, exhibited a higher degree of hypertrophic growth in rainbow trout compared to maraena whitefish, which makes this species particularly successful as an aquaculture species.

Effects of 6 Months of Soy-Enriched High Protein Compared to Eucaloric Low Protein Snack Replacement on Appetite, Dietary Intake, and Body Composition in Normal-Weight Obese Women: A Randomized Controlled Trial

(1) Background: The favorable effects of high protein snacks on body composition and appetite status in lean and athletic populations have been illustrated previously. However, the effects of soy-enriched high protein snacks have not been investigated in women with normal-weight obesity (NWO). Consequently, we aimed at comparing the effects of six months of soy-enriched high protein snack replacement on appetite, body composition, and dietary intake in women with NWO. (2) Methods: One hundred seven (107) women with NWO [(age: 24 ± 3 yrs, BMI: 22.7 ± 2.3 kg/m², body fat percentage (BFP): 38 ± 3.2%)] who were assigned to one of two groups; high protein snack (HP, n = 52) containing 50 g soybean or isocaloric low-protein snack (protein: 18.2 g, carbohydrate: 15 g, fat: 10 g, energy: 210 kcal) or isocaloric low protein snack (LP, n = 55) containing 3.5 servings of fruit (protein: <2 g, carbohydrate: ≈50 g, fat: <1 g, energy: ≈210 kcal) as part of their daily meals (as a snack at 10 a.m.), successfully completed the study interventions. Body mass (BM), body mass index (BMI), waist circumference (WC), BFP, skeletal muscle mass, dietary intake, and appetite levels were evaluated prior to and after the six-month intervention. (3) Results: Appetite (HP = -12 mm and LP = -0.6 mm), energy intake (HP = -166.2 kcal/day and LP = 91.3 kcal), carbohydrate intake (HP = -58.4 g/day and LP = 6.4 g/day), WC (HP = -4.3 cm and LP = -0.9 cm), and BFP (HP = -3.7% and LP = -0.9%) were significantly (p < 0.05) reduced, while skeletal muscle mass (HP = 1.2 kg and LP = 0.3 kg) significantly increased in the HP compared to the LP group, respectively. (4) Conclusions: Six months of a soy-enriched high protein snack replacement decreased appetite and improved body composition in women with NWO. Our findings suggest that soy-enriched high protein snacks are an efficacious strategy for body composition improvement.

Nutritional concerns later in life

In an ageing society, the preservation of health and function is becoming increasingly important. The present paper acknowledges that ageing is malleable and focuses on diets and key nutritional concerns later in life. It presents evidence for the importance of healthful dietary patterns and points towards specific nutritional concerns later in life and conveys three main messages: (1) considering health maintenance and malnutrition risk, both dietary quality in terms of healthful dietary patterns and dietary quantity are important later in life, (2) ageing-related changes in nutrient physiology and metabolism contribute to the risk of inadequacies or deficiencies for specific nutrients, e.g. vitamin D, vitamin B12 and protein and (3) that current food-based dietary guidelines propagate a shift into the direction of Mediterranean type of diets including more plant-based foods. Limited scientific evidence on nutritional requirements of older adults, along with envisaged shifts towards diets rich in plant foods, are challenges that need to be addressed in order to develop tailored nutritional recommendations and dietary guidance for older adults.

Anabolic Resistance of Muscle Protein Turnover Comes in Various Shapes and Sizes

Anabolic resistance is defined by a blunted stimulation of muscle protein synthesis rates (MPS) to common anabolic stimuli in skeletal muscle tissue such as dietary protein and exercise. Generally, MPS is the target of most exercise and feeding interventions as muscle protein breakdown rates seem to be less responsive to these stimuli. Ultimately, the blunted responsiveness of MPS to dietary protein and exercise underpins the loss of the amount and quality of skeletal muscle mass leading to decrements in physical performance in these populations. The increase of both habitual physical activity (including structured exercise that targets general fitness characteristics) and protein dense food ingestion are frontline strategies utilized to support muscle mass, performance, and health. In this paper, we discuss anabolic resistance as a common denominator underpinning muscle mass loss with aging, obesity, and other disease states. Namely, we discuss the fact that anabolic resistance exists as a dimmer switch, capable of varying from higher to lower levels of resistance, to the main anabolic stimuli of feeding and exercise depending on the population. Moreover, we review the evidence on whether increased physical activity and targeted exercise can be leveraged to restore the sensitivity of skeletal muscle tissue to dietary amino acids regardless of the population.

The role of protein hydrolysates for exercise-induced skeletal muscle recovery and adaptation: a current perspective

The protein supplement industry is expanding rapidly and estimated to have a multi-billion market worth. Recent research has centred on understanding how the manufacturing processes of protein supplements may impact muscle recovery and remodeling. The hydrolysed forms of protein undergo a further heating extraction process during production which may contribute to amino acids (AA) appearing in circulation at a slightly quicker rate, or greater amplitude, than the intact form. Whilst the relative significance of the rate of aminoacidemia to muscle protein synthesis is debated, it has been suggested that protein hydrolysates, potentially through the more rapid delivery and higher proportion of di-, tri- and smaller oligo-peptides into circulation, are superior to intact non-hydrolysed proteins and free AAs in promoting skeletal muscle protein remodeling and recovery. However, despite these claims, there is currently insufficient evidence to support superior muscle anabolic properties compared with intact non-hydrolysed proteins and/or free AA controls. Further research is warranted with appropriate protein controls, particularly in populations consuming insufficient amounts of protein, to support and/or refute an important muscle anabolic role of protein hydrolysates. The primary purpose of this review is to provide the reader with a current perspective on the potential anabolic effects of protein hydrolysates in individuals wishing to optimise recovery from, and maximise adaptation to, exercise training.

Protein Source and Quality for Skeletal Muscle Anabolism in Young and Older Adults: A Systematic Review and Meta-Analysis

BACKGROUND

There is much debate regarding the source/quality of dietary proteins in supporting indices of skeletal muscle anabolism.

OBJECTIVE

We performed a systematic review and meta-analysis to determine the effect of protein source/quality on acute muscle protein synthesis (MPS) and changes in lean body mass (LBM) and strength, when combined with resistance exercise (RE).

METHODS

A systematic search of the literature was conducted to identify studies that compared the effects of ≥2 dose-matched, predominantly isolated protein sources of varying "quality." Three separate models were employed as follows: 1) protein feeding alone on MPS, 2) protein feeding combined with a bout of RE on MPS, and 3) protein feeding combined with longer-term resistance exercise training (RET) on LBM and strength. Further subgroup analyses were performed to compare the effects of protein source/quality between young and older adults. A total of 27 studies in young (18-35 y) and older (≥60 y) adults were included.

RESULTS

Analysis revealed an effect favoring higher-quality protein for postprandial MPS at rest [mean difference (MD): 0.014%/h; 95% CI: 0.006, 0.021; P < 0.001] and following RE (MD: 0.022%/h; 95% CI: 0.014, 0.030; P < 0.00001) in young (model 1: 0.016%/h; 95% CI: -0.004, 0.036; P = 0.12; model 2: 0.030%/h; 95% CI: 0.015, 0.045; P < 0.0001) and older (model 1: 0.012%/h; 95% CI: 0.006, 0.018; P < 0.001; model 2: 0.014%/h; 95% CI: 0.007, 0.021; P < 0.001) adults. However, although higher protein quality was associated with superior strength gains with RET [standardized mean difference (SMD): 0.24 kg; 95% CI: 0.02, 0.45; P = 0.03)], no effect was observed on changes to LBM (SMD: 0.05 kg; 95% CI: -0.16, 0.25; P = 0.65).

CONCLUSIONS

The current review suggests that protein quality may provide a small but significant impact on indices of muscle protein anabolism in young and older adults. However, further research is warranted to elucidate the importance of protein source/quality on musculoskeletal aging, particularly in situations of low protein intake.

The effect of daily protein supplementation, with or without resistance training for 1 year, on muscle size, strength, and function in healthy older adults: A randomized controlled trial

BACKGROUND

Protein supplementation alone or combined with resistance training has been proposed to be effective in counteracting age-related losses of muscle mass and strength.

OBJECTIVES

To investigate the effect of protein supplementation alone or combined with light-intensity or heavy-load resistance exercise on muscle size, strength, and function in older adults.

METHODS

In a 1-y randomized controlled trial, 208 healthy older adults (>65 y) were randomly assigned to 1 of 5 interventions: 1) carbohydrate supplementation (CARB); 2) collagen protein supplementation (COLL); 3) whey protein supplementation (WHEY); 4) light-intensity resistance training 3-5 times/wk with whey protein supplementation (LITW); and 5) heavy resistance training 3 times weekly with whey protein supplementation (HRTW). Protein supplements contained 20 g protein + 10 g carbohydrate, whereas CARB contained 30 g of carbohydrates. All intervention groups received the supplement twice daily. The primary outcome was change in the quadriceps cross-sectional area (qCSA). Secondary outcomes included measures of lower extremity strength and power, functional capabilities, and body composition.

RESULTS

There were 184 participants who completed the study. COLL and WHEY did not affect any measured parameter compared to CARB. Compared to WHEY, HRTW improved the qCSA size (between-group difference, +1.68 cm2; 95% CI, +0.41 to +2.95 cm2; P = 0.03), as well as dynamic (+18.4 Nm; 95% CI, +10.1 to +26.6 Nm; P < 10-4) and isometric knee extensor strength (+23.9 Nm; 95% CI, +14.2 to +33.6 Nm; P < 10-5). LITW did not improve the qCSA size, but increased dynamic knee extensor strength compared to WHEY (+13.7 Nm; 95% CI, +5.3 and +22.1 Nm; P = 0.01).

CONCLUSIONS

Recommending protein supplementation as a stand-alone intervention for healthy older individuals seems ineffective in improving muscle mass and strength. Only HRTW was effective in both preserving muscle mass and increasing strength. Thus, we recommend that future studies investigate strategies to increase long-term compliance to heavy resistance exercise in healthy older adults. This trial was registered at clinicaltrials.gov as NCT02034760.

Extraction of protein from food waste: An overview of current status and opportunities

The chief intent of this review is to explain the different extraction techniques and efficiencies for the recovery of protein from food waste (FW) sources. Although FW is not a new concept, increasing concerns about chronic hunger, nutritional deficiency, food security, and sustainability have intensified attention on alternative and sustainable sources of protein for food and feed. Initiatives to extract and utilize protein from FW on a commercial scale have been undertaken, mainly in the developed countries, but they remain largely underutilized and generally suited for low-quality products. The current analysis reveals the extraction of protein from FW is a many-sided (complex) issue, and that identifies for a stronger and extensive integration of diverse extraction perspectives, focusing on nutritional quality, yield, and functionality of the isolated protein as a valued recycled ingredient.

Macronutrient Quality and All-Cause Mortality in the SUN Cohort

No previous study has assessed the relationship between overall macronutrient quality and all-cause mortality. We aimed to prospectively examine the association between a multidimensional macronutrient quality index (MQI) and all-cause mortality in the SUN (Seguimiento Universidad de Navarra) (University of Navarra Follow-Up) study, a Mediterranean cohort of middle-aged adults. Dietary intake information was obtained from a validated 136-item semi-quantitative food-frequency questionnaire. We calculated the MQI (categorized in quartiles) based on three quality indexes: the carbohydrate quality index (CQI), the fat quality index (FQI), and the healthy plate protein source quality index (HPPQI). Among 19,083 participants (mean age 38.4, 59.9% female), 440 deaths from all causes were observed during a median follow-up of 12.2 years (IQR, 8.3–14.9). No significant association was found between the MQI and mortality risk with multivariable-adjusted hazard ratio (HR) for the highest vs. the lowest quartile of 0.79 (95% CI, 0.59–1.06; P_trend = 0.199). The CQI was the only component of the MQI associated with mortality showing a significant inverse relationship, with HR between extreme quartiles of 0.64 (95% CI, 0.45–0.90; P_trend = 0.021). In this Mediterranean cohort, a new and multidimensional MQI defined a priori was not associated with all-cause mortality. Among its three sub-indexes, only the CQI showed a significant inverse relationship with the risk of all-cause mortality.

Limitations with the Digestible Indispensable Amino Acid Score (DIAAS) with Special Attention to Plant-Based Diets: a Review

PURPOSE OF REVIEW

This review describes several limitations of the Digestible Indispensable Amino Acid Score (DIAAS) with a focus on its application to plant-based dietary patterns.

RECENT FINDINGS

Evaluating protein quality in terms of digestibility is paramount to support and optimize the health and well-being of human populations in situations where food insecurity and protein energy malnutrition are widespread. The Food and Agriculture Organization (FAO) of the United Nations has endorsed the DIAAS to replace the previously recommended Protein Digestibility Corrected Amino Acid Score (PDCAAS) for protein quality assessment. While multiple strengths characterize the DIAAS, substantial limitations remain, many of which are accentuated in the context of a plant-based dietary pattern. Some of these limitations include a failure to translate differences in nitrogen-to-protein conversion factors between plant- and animal-based foods, limited representation of commonly consumed plant-based foods within the scoring framework, inadequate recognition of the increased digestibility of commonly consumed heat-treated and processed plant-based foods, its formulation centered on fast-growing animal models rather than humans, and a focus on individual isolated foods vs the food matrix. The DIAAS is also increasingly being used out of context where its application could produce erroneous results such as exercise settings. When investigating protein quality, particularly in a plant-based dietary context, the DIAAS should ideally be avoided.

Protein and physical activity in older persons

PURPOSE OF REVIEW

The aim of this study was to highlight recent evidence on protein requirement and physical activity recommendations in older adults and their interrelationship.

RECENT FINDINGS

Higher protein intake in older adults is beneficial for better physical function, reduced fracture risk, healthy ageing and lower mortality. However, the association between protein quality and health remains inconsistent. Higher physical activity is associated with a lower risk of physical dependence, frailty, cognitive impairment and mortality. Prospectively increasing or even sustaining physical activity can be protective against adverse health outcomes compared with decreasing physical activity. There is a synergistic protective effect of protein intake and physical activity on health. Data on the bidirectional link between protein intake and physical activity are scarce. Whether increasing physical activity can help to increase energy intake (and thus protein intake) and vice versa require further research.

SUMMARY

The key role of protein intake and physical activity in optimizing health in older adults is well established. The synergistic effects of these two modifiable lifestyle factors strengthen the need to consider dietary and physical activity recommendations together. Future research may examine the bidirectional link between diet and physical activity, which could potentially be one of the strategies to increase the uptake of recommendations for protein intake and physical activity in older adults.

Influence of SUB-PRO probiotic on meat productivity of broiler chickens

We studied dynamics of live weight and morphological composition of carcasses in Ross 308 chickens at 1-, 21-, 28-, 34-, 38- and 42-day ages when SUB-PRO probiotic was included in the diet instead of Maxus G feed antibiotic in amount of 100 g/ton of feed. By the age of 42, chickens in the control group (I) reached a live weight of 2234 28.4 g, chickens in the experimental group (II) - 2329 27.3 g, and chickens who took feed antibiotic (III) - 2320 33.4 g. Live weight of chickens of the II group by the age of 42 days exceeded the I group by 95 g or 4.25 % (P 0.05), the III group - by 86 g or 3.85 %. In terms of carcass weight, the experimental group exceeded the control group by 4.60 % (P 0.05), group III - by 4.53 %. The meat productivity of chickens taking antibiotic was not studied further, since that had no practical significance. Over the entire period of rearing, the average daily gain in live weight in control chickens was 52.20 g, in the experimental chickens - 54.46 g. The relative muscle weight in broiler carcasses of the experimental group increased from 55.34 to 66.37 %v from 1 to 42 days of age, while the relative bone weight decreased from 33.23 to 16.78 %. By the age of 42, absolute muscle and bone weight had 123.47- and 51.91-fold increase, respectively, in comparison with diurnal weight. The data of anatomical cutting of chicken carcasses showed that, in terms of muscle and bone content, the most valuable were: breast - 84.63 and 8.25 %, thigh - 75.66 and 12.54 %, respectively; less valuable: drumstick - 67.86 and 20.98 %, wing - 50.58 and 33.53 %, respectively. Diameter of muscle fibers of superficial pectoralis muscle in 42-day-old broilers was 55.20 m; water content - 75.10 %, fat - 1.60 %, protein - 22.31 %. In terms of microbiological parameters, carcass meat meets the requirements of GOST 31468-2012 interstate standard. The inclusion of SUB-PRO probiotic in chicken diet instead of antibiotic does not reduce productivity, but excludes the negative consequences of antibiotic use.

The effects of resistance training with or without peanut protein supplementation on skeletal muscle and strength adaptations in older individuals

Several studies suggest resistance training (RT) while supplementing with various protein supplements can enhance strength and muscle mass in older individuals. However, to date, no study has examined the effects of RT with a peanut protein powder (PP) supplement on these outcomes. Herein, 39 older, untrained individuals (n = 17 female, n = 22 male; age = 58.6 ± 8.0 years; body mass index =28.7 ± 5.8) completed a 6-week (n = 22) or 10-week (n = 17) RT program, where full-body training was implemented twice weekly (ClinicalTrials.gov trial registration NCT04015479; registered July 11, 2019). Participants in each program were randomly assigned to consume either a PP supplement once per day (75 total g powder providing 30 g protein, > 9.2 g essential amino acids, ~ 315 kcal; n = 20) or no supplement (CTL; n = 19). Right leg vastus lateralis (VL) muscle biopsies were obtained prior to and 24 h following the first training bout in all participants to assess the change in myofibrillar protein synthetic rates (MyoPS) as measured via the deuterium-oxide (D₂O) tracer method. Pre- and Post-intervention testing in all participants was conducted using dual energy x-ray absorptiometry (DXA), VL ultrasound imaging, a peripheral quantitative computed tomography (pQCT) scan at the mid-thigh, and right leg isokinetic dynamometer assessments. Integrated MyoPS rates over a 24-h period were not significantly different (p < 0.05) between supplement groups following the first training bout. Regarding chronic changes, there were no significant supplement-by-time interactions in DXA-derived fat mass, lean soft tissue mass or percent body fat between supplementation groups. There was, however, a significant increase in VL thickness in PP versus CTL participants when the 6- and 10-week cohorts were pooled (interaction p = 0.041). There was also a significant increase in knee flexion torque in the 10-week PP group versus the CTL group (interaction p = 0.032). In conclusion, a higher-protein, defatted peanut powder supplement in combination with RT positively affects select markers of muscle hypertrophy and strength in an untrained, older adult population. Moreover, subanalyses indicated that gender did not play a role in these adaptations.

The longitudinal relationship between dietary intake, physical activity and muscle strength among adolescents

The longitudinal relationship between muscle strength, dietary intake and physical activity among adolescents is not well understood. We investigated the trend and longitudinal effects of dietary intakes and physical activity scores on muscle strength in adolescents. This prospective cohort study consisted of 436 adolescents (134 males; 302 females) aged 13 years at baseline (2012) who were followed up at the ages of 15 (2014) and 17 (2016) years, respectively. We measured muscle strength using a calibrated hand dynamometer, estimated dietary intake with a 7-d dietary history and physical activity scores with a validated physical activity questionnaire for older children. A generalised estimating equation was used to examine the effect of dietary intakes and physical activity on muscle strength changes. The analysis was performed separately by sex. The muscle strength for males and females had increased within the 5-year period. The dietary intakes (energy and macronutrients) also increased initially but plateaued after the age of 15 years for both sexes. Females recorded a significant declining trend in physical activity scores compared with males as they grew older. A significant positive longitudinal relationship was found between protein (β = 0·035; P = 0·016), carbohydrate intake (β = 0·002; P = 0·013) and muscle strength among males. However, no longitudinal relationship was found between dietary intake, physical activity and muscle strength among females. Higher protein and carbohydrate intake among males was associated with higher muscle strength but was not observed in females. Nutrition and physical activity focusing on strength building are required in early adolescence and need to be tailored to males and females accordingly.

Relationships of Physical Activity and Diet Quality with Body Composition and Fat Distribution in US Adults

OBJECTIVE

This study aimed to investigate the relationships among physical activity (PA), diet quality, body composition, and fat distribution in a representative sample of US adults.

METHODS

A cross-sectional analysis was conducted using publicly accessible data from the 2011 to 2016 National Health and Nutrition Examination Survey and the Food Patterns Equivalents Database (n = 7,423). Variables from the data sets were analyzed for this study, including PA, two 24-hour dietary recalls, and dual-energy x-ray absorptiometry outputs.

RESULTS

For men, PA and diet quality were inversely associated with the percentage of body fat (β = -0.0042, 95% CI: -0.0084 to -0.0001; β = -0.28, 95% CI: -0.42 to -0.14) and fat mass index (β = -0.0125, 95% CI: -0.0209 to -0.0041; β = -0.56, 95% CI: -0.81 to -0.32); meeting the PA recommendation and having good diet quality provided an additive effect on body fat. A similar pattern was observed in women. Additionally, diet quality was inversely associated with all fat distribution measures in both sexes, whereas PA was positively associated with lean mass measures in men only.

CONCLUSIONS

Increased PA and/or better diet quality were associated with reduced body fat, a healthier fat distribution, and increased lean mass. Further research examining how changes in PA or diet quality influence body composition and fat distribution in adults is warranted.

Protein intakes of pregnant women and children in India-protein quality implications

The recent National Family Health Survey (NFHS-4, 2016) reports a national average of 18% for low birthweight (LBW) and 38% for stunting in children <5 years. Nutrition and environmental influences (chronic enteric pathogenic exposure through poor water, sanitation, and hygiene) are two critical factors that impact the health outcomes of the populxation. This is particularly relevant for vulnerable age groups such as pregnant women and children <5 years, who bear long-lasting and intergenerational consequences of impoverished nutrition and suboptimal living conditions. The present review provides, for the first time, an analysis of indispensable amino acid (IAA) requirements for pregnant women, separately for the second and third trimesters, using protein accretion data from a recent Indian study. Furthermore, using these estimates for pregnancy, and the current IAA requirements for young children, the quality of protein was assessed in Indian diets consumed by pregnant women and children (1-3 and 4-6 years) from national representative rural National Nutrition Monitoring Bureau survey. The assessment was considered in the context of an adverse environment and in relation to outcomes such as LBW, stunting, and underweight. Finally, an assessment was made of the proportion of the surveyed population at risk of dietary quality protein inadequacy and implications for planning nutrition intervention programmes. Specifically, state-wise estimates of the risk of quality protein inadequacy are provided, in addition to evaluations of additional dietary supplementation, which could inform the policy of supplementary nutrition programmes to improve health outcomes.

Healthy Dietary Intake Behavior Potentially Modifies the Negative Effect of COVID-19 Lockdown on Depression: A Hospital and Health Center Survey

Background: The COVID-19 pandemic causes a huge burden for affected countries. Several public health interventions were applied to contain the infection. However, the pandemic itself and the lockdown measure negatively influence people's lifestyles and psychological health. Purpose: To explore determinants of healthy dietary intake and depression, and examine the interaction between healthy dietary intake and COVID-19 lockdown on depression. Methods: A cross-sectional study was conducted at 18 hospitals and health centers from February 14 to May 31, 2020. Data of 8,291 outpatients were collected including patients' characteristics, clinical parameters, health literacy, healthy dietary intake (using the healthy eating score, HES), other health-related behaviors, and depression (using the patient health questionnaire, PHQ). Depression was defined as PHQ score ≥ 10. Results: Protective factors of healthy dietary intake and depression were higher education, better medication payment ability, higher social status, more physical activity, and higher health literacy, whereas older age, ever married, own business or other types of occupation, lockdown, suspected COVID-19 symptoms, and comorbidity were associated with lower HES scores and a higher depression likelihood. Besides, overweight/obesity and alcohol drinking were associated with lower HES scores. As compared with patients not under lockdown and with lowest HES score, those who were under lockdown and with lowest HES score had 10.6 times higher depression likelihood (odds ratio, OR, 10.60; 95% CI 6.88, 16.32; p < 0.001), whereas people with higher HES score had 15% lower depression likelihood (OR 0.85; 95% CI 0.82, 0.89; p < 0.001). Conclusions: Healthy dietary intake and depression were determined by several sociodemographic, clinical, and behavioral factors. Lockdown measure affects people's dietary intake behavior and depression. Importantly, healthy dietary intake potentially modifies the negative effect of lockdown on depression.

Nutrient-dense protein as a primary dietary strategy in healthy ageing: please sir, may we have more?

A progressive decrement in muscle mass and muscle function, sarcopoenia, accompanies ageing. The loss of skeletal muscle mass and function is the main feature of sarcopoenia. Preventing the loss of muscle mass is relevant since sarcopoenia can have a significant impact on mobility and the quality of life of older people. Dietary protein and physical activity have an essential role in slowing muscle mass loss and helping to maintain muscle function. However, the current recommendations for daily protein ingestion for older persons appear to be too low and are in need of adjustment. In this review, we discuss the skeletal muscle response to protein ingestion, and review the data examining current dietary protein recommendations in the older subjects. Furthermore, we review the concept of protein quality and the important role that nutrient-dense protein (NDP) sources play in meeting overall nutrient requirements and improving dietary quality. Overall, the current evidence endorses an increase in the daily ingestion of protein with emphasis on the ingestion of NDP choices by older adults.

Of Sound Mind and Body: Exploring the Diet-Strength Interaction in Healthy Aging

Strength is a vital component of healthy aging. However, “strength” comes in different forms (includes both physical and mental aspects) and can look different at various phases of adult life. Healthy eating and regular exercise are clearly important pillars for strength. This paper proposes a framework that underlines the value of protein foods and resistance exercise for aging strong.

Muscle Protein Synthesis and Whole-Body Protein Turnover Responses to Ingesting Essential Amino Acids, Intact Protein, and Protein-Containing Mixed Meals with Considerations for Energy Deficit

Protein intake recommendations to optimally stimulate muscle protein synthesis (MPS) are derived from dose-response studies examining the stimulatory effects of isolated intact proteins (e.g., whey, egg) on MPS in healthy individuals during energy balance. Those recommendations may not be adequate during periods of physiological stress, specifically the catabolic stress induced by energy deficit. Providing supplemental intact protein (20–25 g whey protein, 0.25–0.3 g protein/kg per meal) during strenuous military operations that elicit severe energy deficit does not stimulate MPS-associated anabolic signaling or attenuate lean mass loss. This occurs likely because a greater proportion of the dietary amino acids consumed are targeted for energy-yielding pathways, whole-body protein synthesis, and other whole-body essential amino acid (EAA)-requiring processes than the proportion targeted for MPS. Protein feeding formats that provide sufficient energy to offset whole-body energy and protein-requiring demands during energy deficit and leverage EAA content, digestion, and absorption kinetics may optimize MPS under these conditions. Understanding the effects of protein feeding format-driven alterations in EAA availability and subsequent changes in MPS and whole-body protein turnover is required to design feeding strategies that mitigate the catabolic effects of energy deficit. In this manuscript, we review the effects, advantages, disadvantages, and knowledge gaps pertaining to supplemental free-form EAA, intact protein, and protein-containing mixed meal ingestion on MPS. We discuss the fundamental role of whole-body protein balance and highlight the importance of comprehensively assessing whole-body and muscle protein kinetics when evaluating the anabolic potential of varying protein feeding formats during energy deficit.

Effects of pre-sleep protein consumption on muscle-related outcomes - A systematic review

OBJECTIVES

The timing of protein intake over the day on muscle mass and strength gains have received interest in the literature. Thus, the aim of this systematic review is to analyze clinical studies that evaluated the acute effects of pre-sleep protein consumption on overnight muscle protein synthesis and the chronic effects on muscle mass and strength.

DESIGNS

Systematic review.

METHODS

A literature search was conducted up to June 2020 according to PRISMA statement and nine articles were included to analyze.

RESULTS

The consumption of 20-40 g of casein approximately 30 min before sleep stimulates whole-body protein synthesis rates over a subsequent overnight period in young and elderly men (preceded or not by resistance exercise, respectively). In addition, pre-sleep protein consumption can augment the muscle adaptive response (muscle fiber cross-sectional area, strength and muscle mass) during 10-12 weeks of resistance exercise in young, but not in elderly men.

CONCLUSIONS

Based on current evidence, the consumption of 20-40 g of casein approximately 30 min before sleep improves protein synthetic response during an overnight recovery period in healthy young adult men, with possible positive effects on muscle mass and strength following prolonged resistance exercise. In elderly, despite the initial evidence regarding the pre-sleep protein enhances overnight muscle protein synthesis rates, the current available evidence is limited precluding to conclude about the chronic effects on skeletal muscle mass or strength. These conclusions need to be taken with caution due to uneven protein intakes between experimental groups. Therefore, more data are needed before further considering pre-sleep protein as an effective nutritional intervention.

Myoprotective Whole Foods, Muscle Health and Sarcopenia: A Systematic Review of Observational and Intervention Studies in Older Adults

Decline in skeletal muscle strength and mass (sarcopenia) accelerates with age, leading to adverse health outcomes and poor quality of life. Diet plays a crucial role in muscle ageing being an important element of a healthy lifestyle. However, unlike single nutrients, such as dietary protein, or dietary patterns, such as the Mediterranean diet, the relationship between individual whole foods and muscle health has not been systematically evaluated. We aimed to investigate which whole foods (meat, fish, eggs, fruit and vegetables, and non-liquid dairy) may be beneficial (myoprotective) for ageing muscle and sarcopenia in adults aged ≥ 50 years. Nineteen observational and nine intervention studies were identified through systematic searches of the four electronic databases (last search: March 2020). The synthesis of findings showed strong and consistent evidence for a beneficial effect of lean red meat on muscle mass or lean tissue mass in both observational and intervention studies. Higher intake of fruit and vegetables was associated with better muscle function in observational studies, but the evidence from intervention studies was scarce. Non-liquid dairy foods were beneficial for muscle mass in both observational and intervention studies. There was moderate evidence for the role of these foods in muscle strength and sarcopenia, and limited or inconclusive evidence for the benefits of other whole foods (e.g., fish, eggs) for muscle health in older adults. Although current nutritional recommendations are often based on a single nutrient approach, further research about the role of protein-rich and other foods in muscle health will allow for the development of guidelines that are based on whole foods, also highlighting the potential importance of non-protein nutrients within these foods for myoprotection in older adults.

Nutritional Supplements to Support Resistance Exercise in Countering the Sarcopenia of Aging

Skeletal muscle plays an indispensable role in metabolic health and physical function. A decrease in muscle mass and function with advancing age exacerbates the likelihood of mobility impairments, disease development, and early mortality. Therefore, the development of non-pharmacological interventions to counteract sarcopenia warrant significant attention. Currently, resistance training provides the most effective, low cost means by which to prevent sarcopenia progression and improve multiple aspects of overall health. Importantly, the impact of resistance training on skeletal muscle mass may be augmented by specific dietary components (i.e., protein), feeding strategies (i.e., timing, per-meal doses of specific macronutrients) and nutritional supplements (e.g., creatine, vitamin-D, omega-3 polyunsaturated fatty acids etc.). The purpose of this review is to provide an up-to-date, evidence-based account of nutritional strategies to enhance resistance training-induced adaptations in an attempt to combat age-related muscle mass loss. In addition, we provide insight on how to incorporate the aforementioned nutritional strategies that may support the growth or maintenance of skeletal muscle and subsequently extend the healthspan of older individuals.

Nutritional Strategies to Offset Disuse-Induced Skeletal Muscle Atrophy and Anabolic Resistance in Older Adults: From Whole-Foods to Isolated Ingredients

Preserving skeletal muscle mass and functional capacity is essential for healthy ageing. Transient periods of disuse and/or inactivity in combination with sub-optimal dietary intake have been shown to accelerate the age-related loss of muscle mass and strength, predisposing to disability and metabolic disease. Mechanisms underlying disuse and/or inactivity-related muscle deterioration in the older adults, whilst multifaceted, ultimately manifest in an imbalance between rates of muscle protein synthesis and breakdown, resulting in net muscle loss. To date, the most potent intervention to mitigate disuse-induced muscle deterioration is mechanical loading in the form of resistance exercise. However, the feasibility of older individuals performing resistance exercise during disuse and inactivity has been questioned, particularly as illness and injury may affect adherence and safety, as well as accessibility to appropriate equipment and physical therapists. Therefore, optimising nutritional intake during disuse events, through the introduction of protein-rich whole-foods, isolated proteins and nutrient compounds with purported pro-anabolic and anti-catabolic properties could offset impairments in muscle protein turnover and, ultimately, the degree of muscle atrophy and recovery upon re-ambulation. The current review therefore aims to provide an overview of nutritional countermeasures to disuse atrophy and anabolic resistance in older individuals.

Reply to "Limitations of the Digestible Indispensable Amino Acid Score (DIAAS) and Choice of Statistical Reporting. Comment on "A Comparison of Dietary Protein Digestibility, Based on DIAAS Scoring, in Vegetarian and Non-Vegetarian Athletes." Nutrients 2019, 11, 3106"

We appreciate the critique of our paper (Ciuris et al [...].

Maximizing Post-exercise Anabolism: The Case for Relative Protein Intakes

Maximizing the post-exercise increase in muscle protein synthesis, especially of the contractile myofibrillar protein fraction, is essential to facilitate effective muscle remodeling, and enhance hypertrophic gains with resistance training. MPS is the primary regulated variable influencing muscle net balance with dietary amino acid ingestion representing the single most important nutritional variable enhancing post-exercise rates of muscle protein synthesis. Dose-response studies in average (i.e., ~80 kg) males have reported an absolute 20 g dose of high quality, rapidly digested protein maximizes mixed, and myofibrillar protein synthetic rates. However, it is unclear if these absolute protein intakes can be viewed in a “one size fits all” solution. Re-analysis of published literature in young adults suggests a relative single meal intake of ~0.31 g/kg of rapidly digested, high quality protein (i.e., whey) should be considered as a nutritional guideline for individuals of average body composition aiming to maximize post-exercise myofibrillar protein synthesis while minimizing irreversible amino acid oxidative catabolism that occurs with excessive intakes of this macronutrient. This muscle-specific bolus intake is lower than that reported to maximize whole body anabolism (i.e., ≥0.5 g/kg). Review of the available literature suggests that potential confounders such as the co-ingestion of carbohydrate, sex, and amount of active muscle mass do not represent significant barriers to the translation of this objectively determined relative protein intake. Additional research is warranted to elucidate the effective dose for proteins with suboptimal amino acid compositions (e.g., plant-based), and/or slower digestion rates as well as whether recommendations are appreciably affected by other physiological conditions such endurance exercise, high habitual daily protein ingestion, aging, obesity, and/or periods of chronic negative energy balance.