Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit

Physical activity and fiber intake beneficial for muscle mass and strength preservation during aging: A comprehensive cross-sectional study in the UK biobank cohort

BACKGROUND

Aging triggers intricate physiological changes, particularly in whole-body fat-free mass (FFM) and handgrip strength, affecting overall health and independence. Despite existing research, the broader significance of how muscle health is affected by the intricate interplay of lifestyle factors simultaneously during aging needs more exploration. This study aims to examine how nutrition, physical activity, and sleep impact on FFM and handgrip strength in middle-aged men and women, facilitating future personalized recommendations for preserving muscle health.

METHODS

The cross-sectional analysis of the UK Biobank involved 45,984 individuals (54 % women) aged 40-70 years with a complete dataset. Multiple linear regression explored determinants of FFM and handgrip strength, considering traditional, socio-demographics, medication use and smoking as covariates, with sex and age (younger and older than 55 years) stratifications.

RESULTS

In older men and women, higher physical activity beneficially affect both FFM (respectively Β = 3.36 × 10-3, p-value = 1.66 × 10-3; Β = 2.52 × 10-3, p-value = 3.57 × 10-4) and handgrip strength (Β = 6.05 × 10-3, p-value = 7.99 × 10-5, Β = 8.98 × 10-3, p-value = 2.95 × 10-15). Similar results were found in fiber intake for FFM in older men and women (respectively B = 3.00 × 10-2, p-value = 2.76 × 10-5; B = 2.68 × 10-2, p-value = 1.78 × 10-9) and handgrip strength (Β = 3.27 × 10-2, p-value = 1.40 × 10-3; Β = 3.12 × 10-2, p-value = 1.34 × 10-5). Other lifestyle factors influence FFM and handgrip strength differently. Key determinants influencing handgrip strength included higher protein intake, lower water intake, higher alcohol intake, and extended sleep duration whereas mainly higher water intake is associated with higher FFM.

CONCLUSIONS

In both men and women, the main factors associated with FFM and handgrip strength are physical activity and fiber intake, which may underlie a connection between gut and muscle health. Given the observed complexity of muscle health in the age and sex strata, further longitudinal research is needed to provide personalized lifestyle recommendations.

Adherence to Mediterranean, Dietary Approaches to Stop Hypertension and Healthy Eating Indices are Associated with Lower Risk of Disability among Puerto Rican Adults from the Longitudinal Boston Puerto Rican Health Study

BACKGROUND

Emerging evidence suggests that poor dietary quality is an important risk factor for disability. However, few studies have compared adherence to dietary patterns and disability, and none among Puerto Rican adults.

OBJECTIVE

This study was designed to examine relationships between three dietary patterns, including DASH, Mediterranean (MeDS), and Healthy Eating Index (HEI-2010), and ∼6-y incidence of activities of daily living (ADL) and instrumental ADL (IADL) disability, and to assess potential mediation by handgrip strength.

METHODS

Data are from the Boston Puerto Rican Health Study (BPRHS), a longitudinal cohort of Puerto Rican adults aged 45-75 y (n=1502). Adherence to dietary pattern variables were derived from food frequency questionnaire (FFQ) data averaged at baseline and ∼2-y. Handgrip strength was assessed at baseline. Cox proportional hazards models were used to assess longitudinal associations between DASH, MeDS, HEI-2010, and incident ∼6-y ADL (and subscales) and IADL disability. Mediation by handgrip strength was also tested.

RESULTS

Participants with higher adherence DASH had lower risk of ADL, ADL mobility, and ADL manual dexterity disabilities (HR = 0.96, 95%CI: 0.91, 0.98; HR = 0.96, 95%CI: 0.92, 0.99; HR = 0.95, 95%CI: 0.92, 0.98, respectively).Higher adherence to MeDS was associated with lower risk of ADL and ADL mobility disabilities (HR = 0.89, 95%CI: 0.81, 0.98; HR = 0.90, 95%CI: 0.82, 1.00), and higher adherence to HEI with lower risk of ADL manual dexterity (HR = 0.98, 95%CI: 0.97, 0.99) in fully adjusted models. Only DASH tended to be associated with IADL (HR = 0.97, 95%CI: 0.94, 1.00). Baseline handgrip strength was a mediator between HEI and ADL manual dexterity (23.7% of the indirect effect was explained through handgrip strength).

CONCLUSIONS

Higher adherence to a healthy diet pattern may decrease risk of disability and may be an important prevention strategy for ADL and IADL disability associated with aging.

Association of ultra-processed food consumption with muscle mass among young and middle-aged US adults

INTRODUCTION

Muscle mass is vital for physical activity and fundamental physiological processes supporting long-term health. While aging is inevitable, certain modifiable factors positively influence muscle preservation and overall well-being. However, the relationship between the consumption of ultra-processed foods (UPF) and muscle mass is not yet clear.

METHODS

This study included 7,173 men and nonpregnant women aged 20-59 years with valid 24-hour dietary recalls and accessible whole-body dual-energy x-ray absorptiometry (DXA) scans from NHANES 2011-2018. UPFs were identified through the NOVA classification system, and the percentage of energy derived from UPF consumption was evaluated in quintiles. Muscle mass measures were derived from DXA scans and quantified by the total and regional muscle mass index (MMI, kg/m²) and appendicular muscle mass index (AMMI, kg/m²). Multivariable-adjusted generalized linear regression models were applied to investigate the association between consumption of UPFs and muscle mass measures overall and by sociodemographic subgroups.

RESULTS

The multivariable-adjusted differences of total MMI from the lowest to highest quintile of UPF consumption were 0 (reference), -0.03 (95% CI, -0.13, 0.07), -0.13 (95%CI, -0.24, -0.04), -0.12 (95% CI, -0.23, -0.01), and - 0.17 (95% CI, -0.27, -0.08) (P for trend < 0.001). Subtotal MMI followed a similar magnitude of associational pattern as total MMI. For trunk MMI, corresponding values from the lowest to highest quintiles of UPF consumption were 0 (reference), -0.02 (95% CI, -0.07, 0.02), -0.05 (95%CI, -0.11, 0.00), -0.07 (95% CI, -0.13, -0.01), and - 0.07 (95% CI, -0.12, -0.01). For AMMI, corresponding values from the lowest to highest quintiles of UPF consumption were 0 (reference), -0.004 (95% CI, -0.07, 0.06), -0.08 (95%CI, -0.14, -0.02), -0.05 (95% CI, -0.11, 0.02), and - 0.10 (95% CI, -0.16, -0.04) (All P for trend < 0.001). While most subgroups maintained similar overall patterns, heterogeneous findings were also observed. For example, the multivariable-adjusted differences in total MMI between the lowest and highest quantile of UPF consumption were - 0.19 (95% CI, -0.32, -0.06) for non-Hispanic Whites, 0.18 (95% CI, 0.01, 0.36) for non-Hispanic Blacks, -0.25 (95%CI, -0.45, -0.04) for Hispanics, -0.25 (95% CI, -0.51, 0.05) for non-Hispanic Asians and - 0.32 (95% CI, -0.75, 0.12) for others (P for interaction < 0.001).

CONCLUSION

Higher consumption of UPFs was significantly associated with lower values of total and regional muscle mass. Specifically, comparing the highest quantile of UPF consumption to the lowest, total MMI decreased by 0.93%, trunk MMI decreased by 0.76%, and AMMI decreased by 1.25%. The differences in associational patterns between UPF consumption and muscle mass across sociodemographic subgroups require further investigation.

Intestinal Taste Receptor Expression and Its Implications for Health: An Integrative Analysis in Female Rats after Chronic Insect Supplementation

Taste receptors are found in the gastrointestinal tract, where they are susceptible to dietary modulation, a key point that is crucial for diet-related responses. Insects are sustainable and good-quality protein sources. This study analyzed the impact of insect consumption on the modulation of taste receptor expression across various segments of the rat intestine under healthy or inflammatory conditions. Female Wistar rats were supplemented with Tenebrio molitor (T) or Alphitobius diaperinus (B), alongside a control group (C), over 21 days under healthy or LPS-induced inflammation. The present study reveals, for the first time, that insect consumption modulates taste receptor gene expression, mainly in the ascending colon. This modulation was not found under inflammation. Integrative analysis revealed colonic Tas1r1 as a key discriminator for insect consumption (C = 1.04 ± 0.32, T = 1.78 ± 0.72, B = 1.99 ± 0.82, p-value <0.05 and 0.01, respectively). Additionally, correlation analysis showed the interplay between intestinal taste receptors and metabolic and inflammatory responses. These findings underscore how insect consumption modulates taste receptors, influencing intestinal function and broader physiological mechanisms.

Protein Nutrition: Understanding Structure, Digestibility, and Bioavailability for Optimal Health

This review discusses different protein sources and their role in human nutrition, focusing on their structure, digestibility, and bioavailability. Plant-based proteins, such as those found in legumes, nuts, and seeds, may contain anti-nutritional factors that impact their bioavailability apart from structural and compositional differences from animal proteins. Animal proteins are generally highly digestible and nutritionally superior to plant proteins, with higher amino acid bioavailability. Alternative protein sources are also processed in different ways, which can alter their structure and nutritional value, which is also discussed.

Preoperative lifestyle modifications combined with a structured exercise protocol on patient outcomes following total knee replacement surgery: A systematic review

BACKGROUND

Medical guidelines recommend structured prehabilitation protocols consisting of lifestyle modifications and exercise to enhance post-operative outcomes for patients undergoing a total knee replacement (TKR). However, current research showing effectiveness is limited and has primarily focused on outcomes of exercise-based prehabilitation.

OBJECTIVES

To investigate whether a structured prehabilitation protocol consisting of exercise and lifestyle modifications improves physical function and patient-reported outcomes following TKR surgery compared with usual care.

DESIGN

Systematic review.

METHODS

Five databases were searched to identify randomised controlled trials comparing structured prehabilitation programs consisting of lifestyle modifications and exercise, with usual care, for those undergoing a TKR. Methodological quality of included studies was assessed via the RoB 2.0 tool and results synthesis via a Grading of Recommendation Assessment, Development and Evaluation approach was performed to determine the certainty evidence for each outcome.

RESULTS/FINDINGS

Four studies were included in this review. Despite a positive trend supporting the inclusion of a structured prehabilitation protocol, additional improvements in post-operative pain, physical function and self-reported function were only seen in one study. Reductions in hospital length of stay were also seen in one study. No additional improvements in post-operative quality of life following prehabilitation were reported.

CONCLUSION

Limited evidence supporting prehabilitation reported in our review is likely attributed to the intervention type, intensity, and delivery model of included studies. However, there remains to be strong evidence supporting the use of a structured prehabilitation protocol consisting of lifestyle modifications and exercise to improve post-operative outcome.

Protein Supplements with Short Peptides Are Better than Complex Protein-Based Supplements on Improving Early Fat-Free Mass Loss Following Bariatric Surgery: A Retrospective Cohort Study

INTRODUCTION

Bariatric surgery (BS) patients are advised to consume protein supplements to prevent fat-free mass (FFM) loss. However, limited research has explored the efficacy of diverse protein presentations on FFM preservation. This study assesses if short peptide-based (SPB) supplements surpass complex protein-based (CPB) supplements in reducing early FFM loss post-surgery.

METHODS

In this retrospective cohort study, 138 patients who underwent BS other than Roux-en-Y-gastric bypass (RYGB) between January 2021 and March 2021 at the Department of Bariatric Surgery of the Third People's Hospital of Chengdu were included for analysis. Patients were divided into two groups based on their consumption of protein supplements after surgery: SPB group and CPB group. Multiple linear regressions separated by sex were employed to examine the associations between SPB supplements and FFM loss and percentage of FFM (%FFM) loss, respectively.

RESULTS

Among participants, 69.6% were female, with a mean age of 33.3 years. In multiple linear regression analyses, SPB supplements were significantly and positively associated with a lower FFM loss in both female (ꞵ =  - 1.14, P = 0.047) and male (ꞵ =  - 2.36, P = 0.024), and were positively associated with a lower %FFM loss in both female (ꞵ =  - 1.83) and male (ꞵ =  - 2.26) but only significant in male (P = 0.049).

CONCLUSION

SPB supplements may be more effective in preventing early FFM loss after BS, compared to CPB supplements, particularly among male patients. Therefore, SPB supplements may be recommended to patients undergoing BS. Further research is needed to validate these findings.

Treatment of Cachexia in Gastric Cancer: Exploring the Use of Anti-Inflammatory Natural Products and Their Derivatives

(1) Background: Gastric cancer is a significant cause of cancer-related mortality worldwide. Weight loss and malnutrition associated with cancer are linked with increased mortality rates and reduced quality of life. Cancer cachexia, characterised by the loss of skeletal muscle, is associated with approximately 20% of cancer-related deaths and differs from malnutrition in that it cannot be fully reversed by nutritional support alone. It is now recognised that the primary pathophysiological process underlying cancer cachexia is chronic inflammation leading to increased calorie consumption. Current treatments that focus on nutritional supplementation, psychological counselling, appetite stimulation and reducing inflammation are lacking in efficacy. This review focuses on the evidence supporting the potential roles of natural anti-inflammatory products and their derivatives including fatty acids, probiotics, amino acids, curcumin, fucoidan, epigallocatechin-3-gallate, ginger, resveratrol and Boswellia serrata in the management of gastric cancer cachexia. (2) Results: While natural anti-inflammatory products show promise in a number of in vitro and in vivo studies, there are only a small number of human studies available. Where present, the evidence base is heterogeneous, with varying study methodologies and outcomes. (3) Conclusions: Natural anti-inflammatory products represent a potential adjunctive therapy for gastric cancer cachexia. Further research, particularly well-designed clinical trials, is needed to elucidate their optimal role, dosing and safety profiles in the management of gastric cancer cachexia.

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.

Diet quality is associated with adipose tissue and muscle mass: the Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND

Aging is associated with changes in body composition, and preventing loss of muscle mass and accumulation of excess adipose tissue in middle-aged adults may reduce age-related conditions at older ages. Dietary intake is one lifestyle factor shown to improve or maintain body composition. However, few studies have examined the Healthy Eating Index2015 (HEI2015), a measure of diet quality, and the association with body composition in adult men and women.

METHODS

Participant data (n = 3017) from the Coronary Artery Risk Development in Young Adults (CARDIA) study were used to examine the associations of the HEI2015 with body composition measures at Year 25 (Y25), including (1) 25 year-change in weight, body mass index (BMI), and waist circumference and (2) a computed tomography (CT) scan at Y25 measured muscle mass, muscle quality (better quality = less lipid within the muscle), and adipose tissue depots visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and adipose within skeletal muscle (intermuscular adipose tissue; IMAT). Dietary intake was assessed by a diet history three times over 20 years, at years 0, 7, and 20. HEI2015, averaged over three exams, was created and categorized into quintiles. Multiple regression analysis evaluated the associations of body composition stratified across quintiles of HEI2015 adjusted for demographic characteristics, energy intake, lifestyle factors, and baseline anthropometric measures as appropriate. Race-sex interaction was tested (Pinteraction  > 0.30).

RESULTS

Over 25 years of follow-up, averaged HEI2015 was significantly and inversely associated with weight gain (Quintile 1 (Q1) 37.3 lb vs. 32.9 in Q5; Ptrend  = 0.01), change in BMI (Q1 5.8 kg/m2 vs. 5.0 in Q5; Ptrend  = 0.005), and change in waist circumference (Q1 17.5 cm vs. 15.2 cm in Q5; Ptrend  < 0.001). By Y25, HEI2015 was inversely associated with VAT Q1 136.8 cm3 vs. 116.6 in Q5; Ptrend  < 0.001) and IMAT volumes (Q1 9.52 vs. 8.12 cm3 in Q5; Ptrend  < 0.001). Although total muscle volume declined (Ptrend  = 0.03), lean muscle mass volume was similar across quintiles (Ptrend  = 0.55). The IMAT/total muscle mass ratio declined across HEI2015 quintiles (Ptrend  < 0.001). Finally, higher HEI2015 was associated with better muscle quality at Y25 (higher value = less lipid within the muscle; Q1 41.1 vs. 42.2 HU in Q5; Ptrend  = 0.002). HEI2015 was nonlinearly, but inversely, associated with SAT (nonlinear P = 0.011).

CONCLUSIONS

Improving diet quality in young to middle-aged adults is a recommended strategy to promote better measures of body composition. Our study findings suggest that healthier food choices may influence body composition.

Athletes' nutritional demands: a narrative review of nutritional requirements

Nutrition serves as the cornerstone of an athlete's life, exerting a profound impact on their performance and overall well-being. To unlock their full potential, athletes must adhere to a well-balanced diet tailored to their specific nutritional needs. This approach not only enables them to achieve optimal performance levels but also facilitates efficient recovery and reduces the risk of injuries. In addition to maintaining a balanced diet, many athletes also embrace the use of nutritional supplements to complement their dietary intake and support their training goals. These supplements cover a wide range of options, addressing nutrient deficiencies, enhancing recovery, promoting muscle synthesis, boosting energy levels, and optimizing performance in their respective sports or activities. The primary objective of this narrative review is to comprehensively explore the diverse nutritional requirements that athletes face to optimize their performance, recovery, and overall well-being. Through a thorough literature search across databases such as PubMed, Google Scholar, and Scopus, we aim to provide evidence-based recommendations and shed light on the optimal daily intakes of carbohydrates, protein, fats, micronutrients, hydration strategies, ergogenic aids, nutritional supplements, and nutrient timing. Furthermore, our aim is to dispel common misconceptions regarding sports nutrition, providing athletes with accurate information and empowering them in their nutritional choices.

The relation between excess adiposity and breast cancer in women: Clinical implications and management

BACKGROUND

Breast cancer (BC) is the most common cancer in women. While the combination of improved screening, earlier detection, and advances in therapeutics has resulted in lower BC mortality, BC survivors are now increasingly dying of cardiovascular disease. Cardiovascular disease in the leading cause of non-cancer related mortality among BC survivors. This situation underscores the critical need to research the role of modifiable cardiometabolic risk factors, such as excess adiposity, that will affect BC remission, long-term survivorship, and overall health and quality of life.

PURPOSE

First, this review summarizes the evidence on the connection between adipose tissue and BC. Then we review the data on weight trends after BC diagnosis with a focus on the effect of weight gain on BC recurrence and BC- and non-BC-related death. Finally, we provide a guide for weight management in BC survivors, considering the available data on the effect of weight loss interventions on BC.

The animal protein hydrolysate attenuates sarcopenia via the muscle-gut axis in aged mice

Age-related muscle loss and dysfunction, sarcopenia, is a common condition that results in poor quality of life in the elderly. Protein supplementation is a potential strategy for preventing sarcopenia and increasing muscle synthesis, but the effectiveness of protein type and level in improving sarcopenia is not well understood. In this study, we compared animal protein hydrolysate (APH), which has a high protein digestibility-corrected amino acid score (PDCAAS) and low molecular weight, with casein as a control group to investigate the effects and mechanisms of sarcopenia improvement, with a particular focus on the gut-muscle axis. APH supplementation improved age-related declines in muscle mass, grip strength, hind leg thickness, muscle protein level, muscle fiber size, and myokine levels, compared to the control group. In particular, levels of plasma cortisol, muscle lipids, and muscle collagen were markedly reduced by APH supplements in the aged mice. Furthermore, APH efficiently recovered the concentration of total SCFAs including acetic, propionic, and isovaleric acids decreased in aged mice. Finally, APH induced changes in gut microbiota and increased production of SCFAs, which were positively correlated with muscle protein level and negatively correlated with pro-inflammatory cytokines. In conclusion, APH can help to inhibit age-related sarcopenia by increasing muscle synthesis, inhibiting muscle breakdown, and potentially modulating the gut-muscle axis.

Exploring high-protein diets in the context of cardiac rehabilitation

The review aims to explore the potential benefit and risk of high-protein diets (HPD) regarding the comorbidity of sarcopoenia and CVD in the setting of cardiac rehabilitation (CR). CR is standard care for individuals who have experienced a cardiac event, but the current practice of predominantly aerobic exercise, a lower-fat diet and weight loss poorly addresses the issue of sarcopoenia. HPD, especially when combined with resistance exercise (RE), may be valuable adjuncts to current CR practice and benefit both muscle and cardiovascular health. Meta-analyses and randomised controlled trials of HPD and CVD risk show beneficial but variable effects regarding weight loss, the lipid profile, insulin resistance and lean body mass in those living with or high risk of CVD. Meta-analyses of prospective cohort studies on hard CVD endpoints favour lower- and plant-protein diets over higher animal protein, but the evidence is inconsistent. HPD augment the strength and muscle gaining benefits of RE in older populations, but there are no published data in those living with CVD providing promising opportunities for CR research. HPD raise concern regarding renal and bone health, the microbiome, branched chain amino acids and environmental sustainability and findings suggest that plant-based HPD may confer ecological and overall health advantages compared to animal-based HPD. However, incorporating RE with HPD might alleviate certain health risks. In conclusion, a largely plant-based HPD is deemed favourable for CR when combined with RE, but further research regarding efficacy and safety in CR populations is needed.

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 Role of Dietary Protein in Body Weight Regulation among Active-Duty Military Personnel during Energy Deficit: A Systematic Review

Active-duty military personnel are subjected to sustained periods of energy deficit during combat and training, leaving them susceptible to detrimental reductions in body weight. The importance of adequate dietary protein intake during periods of intense physical training is well established, where previous research has primarily focused on muscle protein synthesis, muscle recovery, and physical performance. Research on how protein intake may influence body weight regulation in this population is lacking; therefore, the objective of this review was to evaluate the role of dietary protein in body weight regulation among active-duty military during an energy deficit. A literature search based on fixed inclusion and exclusion criteria was performed. English language peer-reviewed journal articles from inception to 3 June 2023 were selected for extraction and quality assessment. Eight studies were identified with outcomes described narratively. The study duration ranged from eight days to six months. Protein was directly provided to participants in all studies except for one. Three studies supplied additional protein via supplementation. The Downs and Black Checklist was used to assess study quality. Five studies were classified as good, two as fair, and one as excellent. All studies reported mean weight loss following energy deficit: the most severe was 4.0 kg. Protein dose during energy deficit varied from 0.5 g/kg/day to 2.4 g/kg/day. Six studies reported mean reductions in fat mass, with the largest being 4.5 kg. Four studies reported mean reductions in fat-free mass, while two studies reported an increase. Results support the recommendation that greater than 0.8 g/kg/day is necessary to mitigate the impact of energy deficit on a decline in lean body mass, while intakes up to 1.6 g/kg/day may be preferred. However, exact recommendations cannot be inferred as the severity and duration of energy deficit varied across studies. Longer and larger investigations are needed to elucidate protein's role during energy deficit in active-duty military.

The associations between anthropometric characteristics and nutritional parameters in male elite rugby union players

The objective was to analyse the associations between anthropometric characteristics and diet in male rugby players according to the playing position. A cross-sectional study was developed. The forwards had higher body weight (107 kg) and fat mass (FM; 12%) than the backs (87.8 kg and 8.47%, respectively) (p < 0.05). The quality of diet needs to improve (KIDMED value of 5.87 and 6.36 for forwards and backs, respectively). Nutritional imbalances, such as deficits in carbohydrates, fibre, calcium, magnesium and vitamin D, and excess of fats, saturated fatty acid, cholesterol and sugars were found. Carbohydrates and proteins intake were significant associated (p < 0.05) with a minor FM. Forwards with a KIDMED index of less than 8 had a significantly higher FM than those who maintained an optimal diet (p < 0.05). The diet of rugby players should be more in line with dietary recommendations and take into account the player position to optimise sports performance.

The moderating role of macronutrient intake in relation to body composition and genotoxicity: A study with gym users

In a cross-sectional study of gymnasium users (both sexes, ages = 41.9 ± 14.8 years), we examined the moderating role of macronutrient intake in relation to body composition and genotoxicity. A questionnaire was administered to evaluate characteristics of the participants. To assess macronutrient consumption, we used 24-h food recalls on three non-consecutive days. Body composition (body fat percentage and muscle mass) was evaluated with a bioimpedance scale. Genotoxicity was assessed with the buccal micronucleus cytome assay. Multiple linear regression models were applied, adjusting for age; sex; tobacco and alcohol consumption; and (with regard to exercise habits) frequency, training time, intensity, and types. Micronucleus frequency was directly associated with body fat and inversely associated with muscle mass. Our study shows that carbohydrate and fat intakes affect body fat percentage and micronucleus frequency in gymnasium users.

Targeting Sarcopenia as an Objective Clinical Outcome in the Care of Children with Spinal Cord-Related Paralysis: A Clinician's View

Muscle loss is consistently associated with immobility and paralysis and triggers significant metabolic and functional changes. The negative effects of sarcopenia are amplified in children who are in the process of building their muscle mass as part of development. Because muscle mass loss is consistently associated with increased morbidity and mortality throughout life, optimizing the size and health of muscles following a neurologic injury is an objective target for therapeutic interventions. This review hypothesizes that muscle mass correlates with functional outcomes in children with paralysis related to spinal cord-related neurologic deficits. We propose that the measurement of muscle mass in this population can be used as an objective outcome for clinical long-term care. Finally, some practical clinical approaches to improving muscle mass are presented.

Assessment of the Use of Food Supplements by Military Personnel: Study Protocol and Results

Due to their specific mode of operation, military personnel are challenged physically as well as mentally. In most countries, the use of food supplements by military personnel is not regulated, and a high prevalence of supplementation is expected. However, data on this are scarce or very limited, without insights into the importance of supplementation for the intake of bioactive substances. Our goal was, therefore, to develop a study protocol to enable an assessment of the prevalence of using food supplements and an estimate of the contribution of supplementation practices to the dietary intake of specific nutrients and other compounds. The protocol was tested in a study of Slovene Armed Forces (SAF) personnel. Data were collected using an anonymous questionnaire in a sample of 470 participants from different military units-about half from the barracks located across the country, and the other half returning from military operations abroad. To provide meaningful results, we recorded the use of food supplements and functional foods available in single-sized portions (i.e., energy drinks, protein bars, etc.). Altogether, 68% of the participants reported supplementation, most commonly with vitamin, mineral, and protein supplements. Military rank, participation status in military operations, and physical activity were the main determinants of the specific supplements used. Surprisingly, a lower prevalence of overall and protein supplementation was observed in subjects returning from military operations abroad (62 vs. 74%) than in personnel stationed in barracks across Slovenia; however, the frequency of the use of energy drinks and caffeine supplements was higher in this population (25 vs. 11%). The study design allowed for estimations of the daily intake of supplemented bioactive compounds. We describe the challenges and approaches used in the study to support similar studies in the future and within other populations.

Association of Sarcopenia with Cognitive Function and Dementia Risk Score: A National Prospective Cohort Study

The relationship between skeletal muscle and cognitive disorders has drawn increasing attention. This study aims to examine the associations of sarcopenia with cognitive function and dementia risk score. Data on 1978 participants (aged 65 years and older) from the 2011 wave of the China Health and Retirement Longitudinal Study, with four follow-up waves to 2018, were used. Cognitive function was assessed by four dimensions, with a lower score indicating lower cognitive function. Dementia risk was assessed by a risk score using the Rotterdam Study Basic Dementia Risk Model (BDRM), with a higher score indicating a greater risk. Sarcopenia was defined when low muscle mass plus low muscle strength or low physical performance were met. We used generalized estimating equations to examine the associations of sarcopenia. In the fully adjusted models, sarcopenia was significantly associated with lower cognitive function (standardized, β = -0.15; 95% CIs: -0.26, -0.04) and a higher BDRM score (standardized, β = 0.42; 95% CIs: 0.29, 0.55). Our findings may provide a new avenue for alleviating the burden of cognitive disorders by preventing sarcopenia.

Dietary protein and muscle wasting in chronic kidney disease: new insights

PURPOSE OF REVIEW

Muscle wasting is an important health problem in chronic kidney disease (CKD) patients. Protein restriction in the diet can be one of the main causes of muscle wasting in this population. In this review, we aimed to investigate the relationship between dietary protein intake and muscle wasting in CKD patients according to recent literature.

RECENT FINDINGS

The one of the main mechanisms responsible for the muscle wasting is the disturbances in skeletal muscle protein turnover. Muscle wasting primarily occurs when the rates of muscle protein breakdown exceed the muscle protein synthesis. Dietary protein intake represents an important role by causing a potent anabolic stimulus resulting a positive muscle protein balance. Compared to studies made in healthy populations, there are very limited studies in the literature about the relationship between dietary protein intake and muscle wasting in the CKD population. Majority of the studies showed that a more liberal protein intake is beneficial for muscle wasting in especially advanced CKD and hemodialysis population.

SUMMARY

Although evaluating muscle wasting in CKD patients, the amount of protein in the diet of patients should also be reviewed. Although excessive protein intake has some negative consequences on this patient group, a more liberated dietary protein intake should be taken into account in this patient group with muscle wasting and especially in dialysis patients.

Potential mechanisms involved in regulating muscle protein turnover after acute exercise: A brief review

It is well established that resistance training increases muscle mass. Indeed, there is evidence to suggest that a single session of resistance training is associated with an increase in muscle protein synthesis in young adults. However, the fundamental mechanisms that are involved in regulating muscle protein turnover rates after an acute bout of physical exercise are unclear. Therefore, this review will briefly focus on summarizing the potential mechanisms behind the growth of skeletal muscle after physical exercise. We also present mechanistic differences that may exist between young and older individuals during muscle protein synthesis and breakdown after physical exercise. Pathways leading to the activation of AKT/mTOR signals after resistance exercise and the activation of AMPK signaling pathway following a HIIT (High intensity interval training) are discussed.

Food for our future: the nutritional science behind the sustainable fungal protein - mycoprotein. A symposium review

Mycoprotein is a well-established and sustainably produced, protein-rich, high-fibre, whole food source derived from the fermentation of fungus. The present publication is based on a symposium held during the Nutrition Society Summer Conference 2022 in Sheffield that explored 'Food for our Future: The Science Behind Sustainable Fungal Proteins'. A growing body of science links mycoprotein consumption with muscle/myofibrillar protein synthesis and improved cardiometabolic (principally lipid) markers. As described at this event, given the accumulating health and sustainability credentials of mycoprotein, there is great scope for fungal-derived mycoprotein to sit more prominently within future, updated food-based dietary guidelines.

Daily Dietary Supplementation with Steamed Soybean Improves Muscle Volume and Strength in Healthy People Lacking Exercise

Various dietary protein supplements are used by the elderly and bedridden to maintain their skeletal muscle mass and functions. High-quality proteins act as an anabolic driver and help to improve muscle strength and performance. Previously, we reported that soy protein significantly attenuates denervation-induced loss of muscle mass and myofiber cross sectional area in mice with inhibition of ubiquitination and degradation of IRS-1 in tibialis anterior muscle. It also increased muscle volume and strength in bedridden patients. In the present study, we investigated the effects of dietary soybean supplementation on muscle functions in taxi drivers lacking vigorous physical exercise. We conducted a case-control study on 25 healthy, male taxi drivers between the ages of 36 and 71 y performing minimal physical exercise. They were divided into two dietary groups: the soybean diet group (n=13) who ate daily meals (dinner) supplemented with 50 g of steamed soybean for 30 d and the control diet group (n=12) who received no soybean supplement. Next, we measured the muscle cross-sectional area (CSA) and muscle strength and function in both the groups before and after 30 d of soybean intake. The body weights of both diet groups did not differ significantly over time. However, after 30 d of soybean supplementation, the soybean-fed group developed significantly higher muscle CSA and grip strength compared to the control groups. In conclusion, dietary soybean supplementation improved muscle function in taxi drivers who lacked exercise.

The combination of isomalto-oligosaccharides (IMO)-based dietary fiber and hypocaloric high-protein diet could improve the anthropometric profile and fasting plasma glucose of healthy adults: A repeated single-arm clinical trial

Background and aims

Meals with high protein and fiber could reduce weight and improve diabetes risk factors. Isomalto-oligosaccharide (IMO), a form of dietary fiber, could induce the afferent signal that causes appetite suppression. However, the direct effect of fiber supplementation in the form of IMO combined with a high-protein diet (HPF) on those parameters is still unknown. This study aims to investigate the effect of HPF on anthropometric parameters and blood glucose regulation of healthy subjects. 
.

Methods

Thirteen healthy subjects were given a hypocaloric high protein diet (HPD) mixed with their prepared meals for two weeks. Followed by the HPF diet for another two weeks. Their anthropometric parameters, such as body composition (total body weight, body fat percentage, and fat-free mass), BMI and waist circumference, and fasting plasma glucose, were measured.

Results

Compared to pre-intervention, HPF could significantly (p ≤ 0.004) reduce the anthropometric parameters and fasting plasma glucose. Compared to HPD, HPF could significantly (p ≤ 0.005) reduce more total body weight, body fat percentage, and BMI. In addition, HPF could induce more satiety than HPD (higher VAS score).

Conclusion

HPF could improve the subject's anthropometric parameters which is obviously beneficial in preventing the risk of developing diabetes.

Adaptation and validation of a protein intake screening tool for a UK adult population

Adequate dietary protein intake is important in human subjects for maintaining muscle turnover, determining the protein content of tissues and thus the preservation of muscle mass and function as we age. A screening tool to assess if an older individual is likely to have a lower dietary protein intake (predicted probability of protein intake ≤1⋅0 g/kg per d), has been developed for a Netherlands dietary profile, but this has not been validated in a UK population. This study aimed to adapt and then validate the protein screening tool for use in a UK population. Amendment of the tool was undertaken using data from UK BioBank and the UK National Diet and Nutrition Survey to reflect protein sources in the UK diet. Validation of the amended version of the protein screener screening tool was conducted using protein intake derived from a food frequency questionnaire (FFQ) in a sample of UK adults (n = 184) (age range 18-91 years) as the reference standard. Using the FFQ, 40 % of respondents (n = 74) reported a protein intake of ≤1⋅0 g per kg body mass. The discriminative accuracy of the amended screener was tested using receiver operating characteristic (ROC) curves. The area under the curve for the ROC was 0⋅731 (95 % CI 0⋅657, 0⋅805), indicating that the amended screener may be a valid tool to screen for individuals consuming ≤1⋅0 g/kg adjusted BM/d in an adult UK population. This protein screener tool is a potential method to screen individuals with a likelihood of habitually consuming protein intakes of ≤1⋅0 g/kg per d. Further validation is needed using a more robust dietary intake methodology and for specific groups, such as older adults. The screener may be applicable across healthcare, clinical and research applications.

Cardio-sarcopenia: A syndrome of concern in aging

Cardiac alterations in structure and function, namely, the left ventricle, have been intensely studied for decades, in association with aging. In recent times, there has been keen interest in describing myocardial changes that accompany skeletal muscle changes in older adults. Initially described as a cardio-sarcopenia syndrome where alterations in myocardial structure were observed particularly among older adults with skeletal muscle sarcopenia, investigations into this syndrome have spurred a fresh level of interest in the cardiac-skeletal muscle axis. The purpose of this perspective is to summarize the background for this "syndrome of concern," review the body of work generated by various human aging cohorts, and to explore future directions and opportunities for understanding this syndrome.

Triglyceride Level- and MTHFR- Specific Mediation Effect of Handgrip Strength on the Association of Dietary Protein Intake and Cognitive Function in the Chinese Elderly

BACKGROUND

Recent findings suggest that both dietary protein intake and hand grip strength (HGS) were associated with cognitive function, however, few studies have been devoted specifically to the mediation effect of HGS on the association of dietary protein with cognitive function.

OBJECTIVES

To confirm the hypothesis that HGS mediated the association of dietary protein intake with cognitive function in the elderly, which was modified by triglyceride level and methylenetetrahydrofolate reductase (MTHFR) gene status.

METHODS

This cross-sectional study included 3,268 participants. Dietary protein intake, HGS, and cognitive function were collected by food frequency questionnaires (FFQ), grip measurements and mini mental state examination (MMSE), respectively. In this mediation analysis, dietary protein intake was entered as independent variable, HGS was entered as mediator, and cognitive function was entered as dependent variable.

RESULTS

HGS significantly mediated the associations of dietary protein (β = 0.0013, 95% CI: 0.0007, 0.0022), animal protein (β = 0.0024, 95% CI: 0.0012, 0.0037), and plant protein intake (β = 0.0011, 95% CI: 0.0001, 0.0023) with cognitive function in total participants, with the mediated proportion of 16.19%, 12.45% and 20.57%, respectively. Furthermore, significant mediation effects of HGS on the associations of dietary protein, animal protein, and plant protein intake with MMSE score were found in the elderly without hypertriglyceridemia or in MTHFR C677T CC/CT carriers.

CONCLUSION

This study suggested that HGS mediated the association of dietary protein intake with cognitive function, and this mediation effect was modified by triglyceride level and MTHFR C677T gene status.

Assessment of gastrointestinal function and its' effect on bone mineral density and body composition in hypermobility spectrum disorder and hypermobile Ehlers-Danlos syndrome

BACKGROUND

Hypermobile Ehlers-Danlos Syndrome (hEDS) and Hypermobility Spectrum Disorders (HSD) are associated with hypermobility, musculoskeletal pain, a decreased bone mineral density (BMD) and gastrointestinal (GI) complications. The role of GI symptoms and diet in BMD has not been established in this population. The GI complications can lead to an energy deficit due to lack of essential macronutrients. The primary objective of this study was to determine the severity of GI symptoms compared to body composition and BMD in individuals with hEDS/HSD. The secondary objective is to examine GI symptoms on energy balance, body composition and strength.

METHODOLOGY

This study was IRB approved. Eighteen female participants (aged 28.2 ± 4.9; BMI 22.5 ± 4.9) with a diagnosis of hEDS or HSD and 18 female healthy control participants (aged 28.1 ± 3.8; BMI 22.8 ±3.9) signed consent to participate. Participants were matched by sex, age, and BMI. The Gastrointestinal Symptom Rating Scale (GSRS) was used to investigate severity of GI symptoms. Dual X-ray absorptiometry was used to determine body composition (body fat%, lean body mass (LBM). BMD was measured by Z- scores of both femurs and lumbar spine. Resting metabolic rate (RMR) was measured using indirect calorimetry and strength was determined using a hand grip dynamometer.

RESULTS

All hEDS/HSD participants reported GI symptoms. There was no difference in body composition between hEDS/HSD and controls. Participants with hEDS/HSD had lower BMD both femoral z scores (p=0.02,0.004) and spine z scores (p= 0.04). There was no difference in caloric intake between groups; yet both groups demonstrated caloric deficits. Additionally, hEDS/HSD consumed less protein and more carbohydrates (p=0.03, p=0.03). There were no differences in grip strength.

CONCLUSIONS

This study identified that pre-menopausal women with hEDS/HSD presented with significant GI complications and lower BMD than age matched controls. The GI complications and the reduced protein intake long-term may have a lasting impact on bone health. This study found that the GSRS identified and quantified GI symptoms in persons with hEDS/HSD. Future studies are needed for the longitudinal effects of a caloric/protein deficit in this population and to help guide future preventive and nutritional treatment approaches in individuals with hEDS/HSD.

Nutrition Behavior and Physical Activity of Middle-Aged and Older Adults in Saudi Arabia

As people get older, their nutritional status deteriorates, resulting in increased vulnerability to chronic diseases. The adoption of a healthy lifestyle has been linked to improved health throughout the aging process. The current study aimed to assess nutritional behaviors, dietary patterns, and physical activity among middle-aged and older adults in Saudi Arabia. An electronic questionnaire was completed between September and November 2021 by 419 participants aged 45 years and older. Of those, 65% reported that nutrition was important to them and 19% stated that they were consuming a healthy diet. Participants reported consuming an average of around 6 servings/week each of fruit and vegetables, with mean intake scores of 5.92 ± 0.25 and 5.57 ± 0.22, respectively. It was reported that around 3 servings/week of red meat, 4 servings/week of poultry, and 1 serving/week of fish were consumed, with mean intake scores of 2.65 ± 0.13, 4.34 ± 0.16, and 1.36 ± 0.08, respectively. Most of the participants (60%) reported being inactive. Middle-aged and older adults living in Saudi Arabia have poor dietary patterns and nutritional behaviors. Education and guidance on nutrition are needed for this population to help them improve their diet and lifestyle.

The role of protein intake in the relationship between egg consumption and body composition in young adults. A mediation analysis

BACKGROUND & AIMS

To date, the literature examining the effects of whole-egg consumption on health outcomes focuses primarily on cardiovascular health markers; however, a significant gap exists in the literature about how egg consumption may influence body composition indicators. The aim of this study was to estimate the association between egg consumption and body composition indicators and to examine whether this relationship is mediated by protein intake in young adults.

METHODS

A cross-sectional study was conducted involving 355 first-year university students (aged 18-30 years) from a Spanish public university. Body composition was measured using bioimpedance and dual-energy X-ray absorptiometry (DXA) and fitness components were determined using the course-navette test. Egg consumption and protein intake (both in g/day/kg of body weight) were determined using a 137-item Food-Frequency Questionnaire. ANCOVA models were used to test the mean differences in body composition indicators (body mass index [BMI], ratio waist circumference/height [WC/height], body fat mass percentage, and body lean mass percentage) by egg consumption categories (<1 egg/week, 1-4 eggs/week, ≥5 eggs/week). Hayes's PROCESS macro was used for mediation analyses.

RESULTS

Participants reporting high egg consumption (≥5 eggs/week) showed significantly lower BMI, WC/height and body fat mass percentage values and higher body lean mass percentage values than those reporting low egg consumption (<1 egg/week) (p < 0.05). However, these relationships were not maintained after adjusting for protein intake. Protein intake acted as a full mediator of the relationships of egg consumption with BMI (indirect effect [IE] = -1.19; 95% CI [-3.33; -0.36]), WC/height (IE = -0.01; 95% CI [-0.04; -0.01]) and body lean mass percentage (IE = 2.99; 95% CI [1.26; 5.73]) as a partial mediator of the relationship be-tween egg consumption and body fat mass percentage (IE = -2.19; 95% CI [-4.92; -0.46]).

CONCLUSIONS

The association between egg consumption and body composition is mediated by protein intake. This finding is important from a public health perspective, suggesting that higher egg consumption (≥5 eggs/week) may lead to a healthier body composition, especially due to higher protein intake.

Effects of Thai native chicken breast meat consumption on serum uric acid level, biochemical parameters, and antioxidant activities in rats

This study aimed to evaluate the effect of a high protein diet comprising breast meat from commercial broiler (BR), Thai native (PD), and commercial broiler × Thai native crossbred (KKU-ONE) chicken on serum uric acid, biochemical parameters, and antioxidant activities in rats. Male Sprague–Dawley rats were divided into four groups. The control group received a standard chow diet, and the other three groups were fed a high protein diet (70% standard diet + 30% BR, PD, or KKU-ONE chicken breast) for five weeks. The PD- and KKU-ONE-fed rats had lower plasma total cholesterol and triglyceride levels than the control rats. A decrease in HDL-c was also observed in rats fed a diet containing BR. Liver weight, liver enzyme, plasma ALP, xanthine oxidase activity, serum uric acid, creatinine, superoxide production, and plasma malondialdehyde levels increased in BR-fed rats. The findings of this study might provide evidence to support the use of Thai native and Thai native crossbred chicken breast meat as functional foods.

Relative protein intake and associations with markers of physical function in those with type 2 diabetes

AIMS

To examine the independent associations between relative protein intake (g kg^-1  day ¹ ) and markers of physical function in those with type 2 diabetes, while also comparing with current guidelines for protein intake.

METHODS

This analysis reports data from the ongoing Chronotype of Patients with Type 2 Diabetes and Effect on Glycaemic Control (CODEC) study. Functional assessments included: Short Physical Performance Battery (SPPB), 60 s sit-to-stand (STS-60), 4-m gait speed, time to rise from a chair (×5) and handgrip strength. Participants also completed a self-reported 4 day diet diary. Regression analyses assessed whether relative protein intake was associated with markers of physical function. Interaction terms assessed whether the associations were modified by sex, age, HbA1c or body mass index (BMI).

RESULTS

413 participants were included (mean ± SD:age = 65.0 ± 7.7 years, 33% female, BMI = 30.6 ± 5.1 kg/m² ). The average total protein intake was 0.88 ± 0.31 g kg^-1  day^-1 . 33% of individuals failed to meet the reference nutrient intake for the United Kingdom (≥0.75 g kg^-1  day^-1 ), and 87% for European recommendations (≥1.2 g kg^-1  day^-1 ). After adjustment, each 0.5 g/kg of protein intake was associated with an 18.9% (95% CI: 2.3, 35.5) higher SPPB score, 22.7% (1.1, 44.3) more repetitions in STS-60, 21.1% (4.5, 37.7) faster gait speed and 33.2% (16.9, 49.5) lower chair rise time. There were no associations with handgrip strength or any interactions.

CONCLUSIONS

Relative protein intake was positively associated with physical function outcomes, even after consideration of total energy intake. As a number of individuals were below the current guidelines, protein intake may be a modifiable factor of importance for people with type 2 diabetes.

Physical Activity and Diet in a Global Pandemic: An Investigation of the Impact of COVID-19 on Factors Relevant for Musculoskeletal Health at Two Different Stages of the Lifecourse

Background

Physical activity, nutrition and other lifestyle factors play important roles in maintaining musculoskeletal health. The coronavirus disease (COVID-19) originated in late 2019, spread globally to be declared a pandemic by the World Health Organisation in March 2020, and led to widespread behaviour change. The aim of this study was to use two existing cohorts, the Hertfordshire Cohort Study (HCS) and Health and Employment After Fifty Study (HEAF), to understand how wave one of the COVID-19 pandemic impacted lifestyle factors associated with musculoskeletal health in the UK.

Methods

125 eligible participants, 65 males and 60 females (drawn from the HCS study, median (IQR) age 84.3 (82.4-86.6) years, all Caucasian, and community dwelling) were contacted by telephone and asked to complete a questionnaire administered by a trained researcher. Data collection occurred over the period July 2020 to February 2021. 2469 participants, 1086 men and 1383 women (drawn from the HEAF study, median age 65.7 (62.0-69.3) years, mostly Caucasian and community dwelling) completed an online questionnaire in March 2021.

Results

In HCS, 47% respondents reported being less physically active than before the pandemic (and only 5% more so), 27% said they consumed less alcohol compared to pre-pandemic times (and only 3% more so), and 18% reported eating less than before, although quality of diet was generally unchanged over this timeframe surveyed. In HEAF, 44% participants said they were less active than before the pandemic, while 17% reported being more active. The majority of participants reported no changes in alcohol consumption and diet; however, 19% said they drank more than before (32% of which was above recommended levels), 16% said their diet was less healthy, and 19% reported eating more than before.

Conclusion

We have reported the experience of the first wave of the COVID-19 pandemic among participants of two Caucasian community dwelling UK cohorts, highlighting the impact of the pandemic on lifestyle factors associated with musculoskeletal health. Changed physical activity levels were reported in a high proportion of respondents in both studies; an investigation of reversibility of these changes is required.

The Association Between Total Protein Intake and All-Cause Mortality in Middle Aged and Older Korean Adults With Chronic Kidney Disease

Background and Aims

Over the past decades, the optimum protein intake for patients with chronic kidney disease (CKD) has been an important, controversial issue. Dietary protein restriction has been commonly recommended for patients with CKD for preserving kidney function. However, evidence of the associations between long-term protein intake and mortality is not consistent in patients with CKD. Therefore, we aimed to examine the associations between total protein intake and all-cause mortality in Korean adults with CKD.

Methods

From three sub-cohorts of the Korean Genome and Epidemiology Study (KoGES) starting from 2001, total 3,892 participants with eGFR < 60 mL/min/1.73 m² (CKD stage 3–5) were included in this study. Dietary data were collected using food-frequency questionnaires at baseline. Deaths were followed from 2001 to 2019. Cox proportional hazards regression model was used to evaluate the association between protein intake and all-cause mortality.

Results

During a median follow-up (min-max) of 11.1 years (0.3–15.1), 602 deaths due to all causes of mortality were documented. After adjustment for covariates, higher total protein intake was not associated with all-cause mortality [highest vs. lowest quintile of total protein intake (g/kg/day) and proportion (%) (Q5 vs. Q1), HR = 1.14 (0.75–1.72), and HR = 0.87 (0.67–1.13)] in CKD stage 3–5 patients.

Conclusion

Dietary protein intake was not associated with mortality from all causes in patients with CKD. Further research is needed to establish optimal protein intake levels and examine the impact of the dietary source of protein on various health outcomes and mortality in CKD.

The effects of acute arginine supplementation on neuroendocrine, metabolic, cardiovascular, and mood outcomes in younger men: a double-blind placebo controlled trial

Objectives:

Arginine is an amino-acid supplement and precursor for nitric-oxide synthesis, which affects various biologic processes. The objective of this study was to determine the effects of arginine supplementation on growth hormone (GH) and metabolic parameters.

Methods:

Thirty physically active, healthy men (age 18–39 y; body mass index: 18.5–25 kg/m²) were randomized in a double-blind, placebo-controlled, crossover trial. Arginine (10 g) and placebo (0 g) beverages were consumed after an overnight fast. Blood samples were collected at baseline and 1.5, 3.0, and 24 h after supplementation. The primary outcomes were serum GH and metabolomics. Also, amino acids, glucose, insulin, triacylglycerols, thyroid hormones, testosterone, cortisol, dehydroepiandrosterone, and mood state were assessed. Individuals with detectable increases in GH were analyzed separately (responders: n = 16; < 0.05 ng/mL at 1.5 h). Repeated-measure analyses of variance estimated the treatment effects at each timepoint.

Results:

Arginine levels increased at 1.5 h (146%) and 3.0 h (95%; P ≤ 0.001) and GH (193%) and thyroid-stimulating hormone (TSH; 10%) levels at 24 h (P < 0.05) after arginine versus placebo consumption. Arginine versus placebo increased glucose levels at 1.5 h (5%) and 3.0 h (3%; P ≤ 0.001). Arginine versus placebo did not affect other dependent measures, including mood state (P > 0.05), but changes in the urea, glutamate, and citric-acid pathways were observed. Among responders, arginine versus placebo increased GH at 1.5 h (37%), glucose at 1.5 h (4%) and 3.0 h (4%), and TSH at 24 h (9%; P < 0.05). Responders had higher levels of benzoate metabolites at baseline and 1.5 h, and an unknown compound (X-16124) at baseline, 1.5 h, and 24 h that corresponds to a class of gut microbes (P < 0.05).

Conclusions:

Arginine supplementation modestly increased GH, glucose, and TSH levels in younger men. Responders had higher benzoate metabolites and an unknown analyte attributed to the gut microbiome. Future studies should examine whether the increased prevalence of these gut microorganisms corresponds with GH response after arginine supplementation.

Glycomacropeptide in PKU-Does It Live Up to Its Potential?

The use of casein glycomacropeptide (CGMP) as a protein substitute in phenylketonuria (PKU) has grown in popularity. CGMP is derived from κ casein and is a sialic-rich glycophosphopeptide, formed by the action of chymosin during the production of cheese. It comprises 20–25% of total protein in whey products and has key biomodulatory properties. In PKU, the amino acid sequence of CGMP has been adapted by adding the amino acids histidine, leucine, methionine, tyrosine and tryptophan naturally low in CGMP. The use of CGMP compared to mono amino acids (L-AAs) as a protein substitute in the treatment of PKU promises several potential clinical benefits, although any advantage is supported only by evidence from non-PKU conditions or PKU animal models. This review examines if there is sufficient evidence to support the bioactive properties of CGMP leading to physiological benefits when compared to L-AAs in PKU, with a focus on blood phenylalanine control and stability, body composition, growth, bone density, breath odour and palatability.

Interaction effect of systemic inflammation and modifiable rheumatoid cachexia risk factors on resting energy expenditure in patients with rheumatoid arthritis

Background

In rheumatoid cachexia (RC), high resting energy expenditure (REE) is associated with loss of muscle mass driven by proinflammatory cytokines. The objectives of this study were to investigate parameters associated with RC, and the interaction between systemic inflammation and modifiable risk factors for RC on REE.

Methods

Thirty-five rheumatoid arthritis (RA) and nineteen non-RA controls comparable in age, sex, race and BMI underwent measures of REE by indirect calorimetry. Clinical, dietary, body composition and physical function data were collected. Homeostasis model assessment for insulin resistance (HOMA-IR) and serum interleukin-6 (IL-6) were used as parameters of IR and systemic inflammation, respectively. Regression models tested association between REE and dependent variables, including pre-specified interaction tests involving HOMA-IR and IL-6 and dietary intake of protein per weight (PPW) and IL-6.

Results

RA subjects were mostly women (94%) and had a median age of 54 years (50.5, 70) and BMI of 30.5 kg/m2 (26.1, 36.9). We observed a significant interaction effect between PPW and serum IL-6 on REE among RA subjects in the multiple regression model among RA. The upper tertile of PPW demonstrated a significant negative correlation between REE and IL-6 (β=-19.97, 95% CI [-35.41, -4.54], p=0.01). The lower tertile of PPW demonstrated a significant positive correlation between REE and IL-6 (β=42.24, 95% CI [4.25, 80.23], p=0.03).

Conclusions

While IR can lead to muscle catabolism, IR was not significantly associated with REE in RA individuals. Higher dietary protein intake could attenuate the effect of systemic inflammation on REE in RA patients.

Branched Chain Amino Acid Supplementation to a Hypocaloric Diet Does Not Affect Resting Metabolic Rate but Increases Postprandial Fat Oxidation Response in Overweight and Obese Adults after Weight Loss Intervention

Background: Branched chain amino acids (BCAA) supplementation is reported to aid in lean mass preservation, which may in turn minimize the reduction in resting metabolic rate (RMR) during weight loss. Our study aimed to examine the effect of BCAA supplementation to a hypocaloric diet on RMR and substrate utilization during a weight loss intervention. Methods: A total of 111 Chinese subjects comprising 55 males and 56 females aged 21 to 45 years old with BMI between 25 and 36 kg/m² were randomized into three hypocaloric diet groups: (1) standard-protein (14%) with placebo (CT), (2) standard-protein with BCAA, and (3) high-protein (27%) with placebo. Indirect calorimetry was used to measure RMR, carbohydrate, and fat oxidation before and after 16 weeks of dietary intervention. Results: RMR was reduced from 1600 ± 270 kcal/day to 1500 ± 264 kcal/day (p < 0.0005) after weight loss, but no significant differences in the change of RMR, respiratory quotient, and percentage of fat and carbohydrate oxidation were observed among the three diet groups. Subjects with BCAA supplementation had an increased postprandial fat (p = 0.021) and decreased postprandial carbohydrate (p = 0.044) oxidation responses compared to the CT group after dietary intervention. Conclusions: BCAA-supplemented standard-protein diet did not significantly attenuate reduction of RMR compared to standard-protein and high-protein diets. However, the postprandial fat oxidation response increased after BCAA-supplemented weight loss intervention.

Diet and Chronic Non-Cancer Pain: The State of the Art and Future Directions

Nutrition plays an important role in pain management. Healthy eating patterns are associated with reduced systemic inflammation, as well as lower risk and severity of chronic non-cancer pain and associated comorbidities. The role of nutrition in chronic non-cancer pain management is an emerging field with increasing interest from clinicians and patients. Evidence from a number of recent systematic reviews shows that optimising diet quality and incorporating foods containing anti-inflammatory nutrients such as fruits, vegetables, long chain and monounsaturated fats, antioxidants, and fibre leads to reduction in pain severity and interference. This review describes the current state of the art and highlights why nutrition is critical within a person-centred approach to pain management. Recommendations are made to guide clinicians and highlight areas for future research.

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 Intake Is Positively Associated with Appendicular Lean Mass and Handgrip Strength among Middle-Aged US Adults

BACKGROUND

Sarcopenia, a progressive loss of skeletal muscle mass and strength, can begin in the 4th decade of life. Protein intake predicts skeletal muscle mass and strength among older adults, but knowledge of similar associations among middle-aged adults is lacking.

OBJECTIVES

We aimed to assess associations between protein intake and skeletal muscle mass, characterized by appendicular lean mass adjusted for BMI [in kg/m2 (ALMBMI)], and muscle strength, represented by handgrip strength adjusted for BMI (GSMAXBMI), among middle-aged adults.

METHODS

We analyzed cross-sectional data from 1209 men and 1208 women aged 40-59 y in the 2011-2014 NHANES. Protein intake per kilogram actual body weight (BW), assessed by two 24-h recalls, was examined as continuous and categorical parameters [low (<RDA, 0.8 g/kg BW), moderate (≥RDA, <1.2 g/kg BW), and high (≥1.2 g/kg BW)]. ALM was measured using DXA, and GSMAX was measured using handgrip dynamometer. "Low lean mass" and "weakness" were defined using NIH criteria for ALMBMI and GSMAXBMI, respectively. Linear and logistic regression models were performed.

RESULTS

Among middle-aged adults, 15.6% of men and 13.4% of women had low lean mass and 3.5% of men and 2.3% of women exhibited weakness. Protein intakes per kilogram BW were positively associated with ALMBMI and GSMAXBMI among men and women after adjustment for age, race/Hispanic origin, physical activity, and self-rated health. Compared with the moderate protein group, the high protein group had a higher GSMAXBMI and the low protein group had a lower GSMAXBMI among men and women. The low protein group had a lower ALMBMI (women) and had a higher OR for low lean mass (men) compared with the moderate protein group.

CONCLUSIONS

Higher protein intakes were associated with greater ALMBMI and GSMAXBMI in this representative sample of US middle-aged adults. Our findings highlight the need for further research on dietary protein as a potential modifying factor of sarcopenia risk in middle age.

Kimchi cabbage (Brassica rapa L.) by-products treated with calcium oxide and alkaline hydrogen peroxide as feed ingredient for Holstein steers

This study aimed to investigate the effects of Kimchi cabbage by-products either treated or untreated with calcium oxide (CaO) and alkaline hydrogen peroxide (AHP) as substitutional ingredient of total mixed ration (TMR) on in vitro fermentation, in situ disappearance and growth performance of Holstein steers. Cannulated Holstein (600 ± 47 kg) was used for both the in vitro and in situ experiments. The treatments used were TMR only (CON), TMR + 30% Kimchi cabbage by-products fresh matter (FM) basis (TC), TMR + 30% Kimchi cabbage by-products FM basis + 5% CaO FM basis (TCC), and TMR + 30% Kimchi cabbage by-products FM basis + 5% CaO FM basis + 3.22% AHP FM basis (TCCA). For in vivo experiment, thirty-four Holstein steers (273 ± 45 kg) were subjected to a 150-day feeding trial, divided into two groups: CON and TC. In the in vitro experiment, pH of TCCA was greatest (p < 0.05) among other treatments at all incubation times. Ammonia nitrogen and volatile fatty acid concentrations were not significantly different for each treatment. However, butyrate was greater (p < 0.05) in TCC and CON than in both TC and TCCA. During in situ experiment, the dry matter (DM) disappearance was greatest (p < 0.05) in TCCA among other treatments. Also, disappearance of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were observed greatest (p > 0.05) in TCCA treatment. In the in vivo experiment, average daily gain (ADG) did not differ between CON and TC. In blood profile analysis, alanine aminotransferase, aspartate aminotransferase, glucose, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and total protein concentration were not significantly different between treatments. But, creatinine concentration was greater (p < 0.05) in TC than in CON. Overall results suggest that Kimchi cabbage by-products either treated or untreated with CaO and AHP can be used as substitutional ingredient in TMR for Holstein steers.

Effect of Coconut and Chestnut Flour Supplementations on Texture, Nutritional and Sensory Properties of Baked Wheat Based Bread

Wheat bread, produced by the single-phase method, is a common food consumed all over the world. Due to changes in lifestyle and nutritional trends, alternative raw materials are sought to increase the nutritional value and improve the taste of daily consumed products. Additionally, customers seek a wide variety of foods, especially when it comes to basic foods. Nuts, such as coconuts or chestnuts, might provide an attractive flavour with benefits to the nutritional quality. In this study, the effect of substituting wheat flour with coconut or chestnut flour (flour contribution level: 5, 10, 15, 30, 50% w/w), was evaluated in terms of the breads specific volume, texture, colour, nutritional composition, and dietary fibre fraction contents. Moreover, a sensory evaluation was conducted to assess potential consumer acceptance. Based on the consumer's perception, the overall acceptance of bread with 15% w/w of coconut and chestnut flour was in privilege compared to the control sample. As a result, taking all of the tested parameters into account, the breads with 5, 10, and 15% supplementation of chestnut or coconut flour were still of good quality compared to the wheat bread and their fibre content was significantly higher.

Functionality of Bread and Beverage Added with Brosimum alicastrum Sw. Seed Flour on the Nutritional and Health Status of the Elderly

Physiological changes in elderly individuals (EI) can contribute to nutritional deterioration and comorbidities that reduce their quality of life. Factors such as diet can modulate some of these effects. The aim was to evaluate the functionality of foods added with Brosimum alicastrum Sw. seed flour in EI. EI (n = 23) living in nursing home conditions agreed to participate. A control stage was carried out (30 days) and subsequently, an intervention stage (30 days) was realized in which a muffin and a beverage, designed for EI, were added to the participants’ their usual diet. In both stages, anthropometric parameters, body composition, nutritional status, dietary intake, sarcopenic status, cognitive and affective states, biometric parameters, and total phenolic compounds (TPC), and antioxidant capacity in foods and plasma of EI were determined. The results showed that the consumption of the foods improved the energy intake and preserved the muscle reserves of the EI. The EI gained body weight (+1.1 kg), increased their protein (+18.6 g/day; 1.5 g/kg BW/day), dietary fiber (+13.4 g/day), iron (+4.4 mg/day), zinc (+1.8 mg/day), folic acid (+83.4 µg/day) consumption while reducing their cholesterol (−66 mg/day) and sodium (−319.5 mg/day) consumption. LDL-C lipoproteins reduced (14.8%) and urea (33.1%) and BUN (33.3%) increased. The TPC increased (7.8%) in the plasma, particularly in women (10.7%). The foods improve the EI nutritional status, and this has a cardiovascular protective effect that can benefit the health of the EI.