Protein Distribution and Muscle-Related Outcomes: Does the Evidence Support the Concept?

Combined mediterranean diet-based sustainable healthy diet and multicomponent training intervention impact on plasma biomarkers and metabolome in older adults

BACKGROUND AND AIMS

Healthy dietary patterns and exercise practices have been associated with improved metabolic and inflammatory profiles. However, studies regarding the combined effect of these interventions on plasma biomarkers and metabolome in older adults are sparser. The primary aim of this study was to investigate the impact of a combined Mediterranean Diet-based Sustainable Healthy Diet (SHD) and Multicomponent Training (MT) intervention on the plasma biomarkers and metabolome and how dietary intake and exercise could modulate these effects.

METHODS

SHD intervention included a weekly supply of Mediterranean Diet-based SHD food and four nutrition sessions involving a Mediterranean-Diet culinary workshop, and the exercise program included 50-min MT group sessions, held three times a week, lasting both 12 weeks. Plasma biomarkers were obtained through standard biochemical analysis. A proton (1H) nuclear magnetic resonance (NMR) spectroscopy-based metabolomics approach was used to study the metabolome in blood plasma. Repeated measures ANOVA were performed and adjusted for confounders.

RESULTS

SHD + MT intervention significantly decreased HDL-C and calcium. SHD + MT showed some changes in common with the SHD and MT group, namely a significant decrease in citrate levels (p = 0.009 for SHD + MT; p = 0.037 for SHDT) and an increase in pyruvate (p < 0.001 for MT and SHD + MT). The SHD + MT group also revealed specific changes in the levels of some amino acids (decrease in alanine, glutamine and lysine: p = 0.026; p < 0.001; p = 0.038, respectively). Increases in formate (p = 0.025) and unsaturated lipids (p = 0.011) are consistent with changes in energy and lipoprotein metabolism.

CONCLUSION

Our data show that a combined lifestyle intervention program, including a Mediterranean Diet-based SHD and MT, could modulate biomarker and metabolome and there seems to be a metabolic path associated to these interventions in older adults. Due to its wide-ranging relevance, it is pertinent to assess to what extent combined SHD and MT can contribute to better clinical profiles.

Distribution of daily protein intake and appendicular skeletal muscle mass in healthy free-living Chinese older adults

AIMS

Evidence regarding impact of protein intake distribution on skeletal muscle mass in older adults is limited and inconsistent. This study aims to investigate the relationship of evenness of dietary protein distribution and number of meals exceeding a threshold with appendicular skeletal muscle mass (ASM) in healthy and free-living Chinese older adults.

METHODS

Repeated measured data of 5689 adult participants aged ≥ 60 years from the China Health and Nutrition Survey (CHNS) 2015 and 2018 waves were analyzed. Mixed-effects linear regression model was performed to examine the relationship between coefficient of variance (CV) of protein intake across meals, number of meals ≥ 0.4 g protein/kg BW and ASM, respectively. Analyses were conducted separately for male and female.

RESULTS

The average CV of protein intake in each wave was in the range of 0.34-0.35. More than 40% male and female participants in each wave had no meal reaching 0.4 g protein/kg BW. Female participants in the highest quartile of protein intake CV had significantly lower ASM (β = -0.18, 95%CI = -0.32, -0.04) compared with those in the lowest quartile, after adjustment for multiple confounders. Significant negative trends were observed across dietary protein CV quartiles with ASM both in male (P trend = 0.043) and female (P trend = 0.007). Significant positive association between number of meals exceeding 0.4 g protein /kg BW and relative ASM were observed in females (2 meals vs. 0 meal: β = 0.003, 95%CI = 0.0007,0.006;≥3 meals vs. 0 meal: β = 0.008, 95%CI = 0.003,0.013), after adjusting for multiple covariates.

CONCLUSIONS

A more even-distributed protein intake pattern and more meals reaching protein intake threshold were respectively associated with higher appendicular skeletal muscle mass in healthy and free-living older Chinese adults. Prospective studies and intervention trials are needed to confirm these cross-sectional findings.

Risk factors for low muscle mass, malnutrition, and (probable-) sarcopenia in adults with or without a history of cancer in the UK Biobank

BACKGROUND AND AIMS

Early identification of people at risk of cancer-related malnutrition, low muscle mass (LMM) and sarcopenia is crucial to mitigate the impact of adverse outcomes. This study investigated risk factors associated with LMM, malnutrition and (probable-) sarcopenia and whether these varied in people with or without a history of cancer.

METHODS

Participants in the UK Biobank, with or without a history of cancer, who completed the Oxford WebQ at the baseline assessment were included. LMM was estimated from fat-free mass derived from bioelectrical impedance analysis, and low muscle strength from handgrip strength, and used to identify probable or confirmed sarcopenia following the European Working Group on Sarcopenia in Older People 2 definition. The Global Leadership Initiative on Malnutrition criteria were applied to determine malnutrition. Generalised linear models were used to estimate prevalence ratios (PR) for associations between risk factors (clinical, functional, nutritional) and study outcomes.

RESULTS

Overall, 50,592 adults with (n = 2,287, mean ± SD 59.7 ± 7.1 years) or without (n = 48,305, mean ± SD 55.8 ± 8.2 years) cancer were included. For all participants (PRs [cancer, without cancer]), slow walking pace (PR 1.85; 1.99), multimorbidity (PR 1.72; 1.51), inflammation (PR 2.91; 2.07), and low serum 25(OH)D (PR 1.85, 1.44) were associated with higher prevalence of LMM, while higher energy intake (PR 0.55; 0.49) was associated with lower prevalence. Slow walking pace (PR 1.54 [cancer], 1.51 [without cancer]) and higher protein intake (PR 0.18 [cancer]; 0.11 [without cancer]) were associated with increased or decreased prevalence of malnutrition, respectively regardless of cancer status. Multimorbidity was the only common factor associated with higher prevalence (PR 1.79 [cancer], 1.68 [without cancer]) of (probable-)sarcopenia in all participants.

CONCLUSION

Risk factors for LMM and malnutrition were similar in adults with and without cancer, although these varied between LMM and malnutrition. These findings have implications for the future of risk stratification, screening and assessment for these conditions and the development or modification of existing screening tools.

Are higher protein intake and distribution of protein intake related to higher appendicular muscle mass among an older Japanese population?: A cross-sectional analysis of the National Health and Nutrition Survey 2017

AIM

Protein intake is an important component in retaining muscle mass, especially among older people. This study examined the relationship between total protein intake and/or the distribution of protein intake in each meal and appendicular muscle mass, using data from the National Health and Nutrition Survey (NHNS) in Japan.

METHODS

Data from the NHNS were re-analyzed in this study. We used data from a one-day dietary record, physical examination, and lifestyle questionnaire completed by 1766 participants aged over 60 years. Appendicular muscle mass was assessed by multiple-frequency bioimpedance measurement. Leucine intake was calculated by the weighted average amino acid content from all 98 food subcategories used in the NHNS, based on amino acid composition data in the 2020 Standard Tables of Food Composition.

RESULTS

Participants with higher protein intake showed significantly higher appendicular muscle mass. This relationship was independent of physical activity, including steps taken per day, exercise habit, and physical labor. Frequent intake of ≥0.4 g protein/kg/meal was not related to appendicular muscle mass. The combination of higher total protein intake and higher physical activity seemed to have the largest association with appendicular muscle mass.

CONCLUSIONS

Higher protein intake may be related to higher appendicular muscle mass, independent of higher physical activity, among older Japanese people. Geriatr Gerontol Int 2024; 24: 634-640.

Timing matters? The effects of two different timing of high protein diets on body composition, muscular performance, and biochemical markers in resistance-trained males

Background

It is unclear whether resistance training in combination with different timing of protein intake might have differential effects on muscle hypertrophy, strength, and performance. Therefore, we compared the effects of 8 weeks of resistance training combined with two different high-protein diet strategies (immediately pre-and after, or 3 h pre and after exercise) in resistance-trained males.

Methods

Forty resistance-trained males (24 ± 4 years) performed 8 weeks of resistance training combined with 2 g kg-1 d-1 protein. Body composition, muscular performance, and biochemical markers were assessed pre and post-intervention.

Results

Nine participants (four from 3 h group and five from the immediate group) withdrew from the study. Therefore, 31 participants completed the study. All measures of skeletal muscle mass, Australian pull-up, and muscle strength, significantly increased post-intervention in both groups (p < 0.05). The biochemical marker urea also significantly increased from pre to post in both groups (p < 0.05). There were no significant between-group differences (p > 0.05).

Conclusion

High-protein diet enhances muscular performance and skeletal muscle mass in resistance-trained males, irrespective of intake time. Consequently, the total daily protein intake appears to be the primary factor in facilitating muscle growth induced by exercise.

Effect of breakfast protein intake on muscle mass and strength in adults: a scoping review

BACKGROUND

The distribution of protein intake throughout the day is frequently skewed, with breakfast having the lowest protein intake across all age groups. There is no review that addresses the association between breakfast protein intake and muscle mass and strength.

OBJECTIVE

This scoping review aims to summarize the literature on the relationship between protein intake during breakfast and muscle mass and strength in adults.

METHODS

This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. Two independent reviewers screened and appraised the articles identified from 3 electronic databases (Medline, Web of Science, and Scopus) that focused on protein intake per meal and its impact on muscle-related outcomes.

RESULTS

A total of 14 763 articles were retrieved from 3 databases, and after the screening process, 15 articles were included for analysis. Approximately 58.8% of findings from 11 studies examining the association between high protein intake during breakfast and muscle mass indicated an increase in muscle mass among participants. Half of 6 studies (50.0%) exploring the relationship between high protein intake at breakfast and muscle strength demonstrated an increase in muscle strength. Consuming high amounts of protein at breakfast or more protein in the morning than in the evening was associated with an increase in the skeletal muscle index and lean body mass.

CONCLUSION

Protein consumption at breakfast revealed potential benefits in increasing muscle mass across 5 studies involving an elderly population and 2 studies encompassing middle-aged women and young men in our review. However, the relationship between protein intake at breakfast and muscle strength remains unclear. Further high-quality randomized controlled trials are required to examine whether adults can preserve skeletal muscle health outcomes by consuming higher amounts of protein at breakfast.

"Diet for the prevention and management of sarcopenia"

Sarcopenia is a geriatric condition characterized by a progressive loss of skeletal muscle mass and strength, with an increased risk of adverse health outcomes (e.g., falls, disability, institutionalization, reduced quality of life, mortality). Pharmacological remedies are currently unavailable for preventing the development of sarcopenia, halting its progression, or impeding its negative health outcomes. The most effective strategies to contrast sarcopenia rely on the adoption of healthier lifestyle behaviors, including adherence to high-quality diets and regular physical activity. In this review, the role of nutrition in the prevention and management of sarcopenia is summarized. Special attention is given to current "blockbuster" dietary regimes and agents used to counteract age-related muscle wasting, together with their putative mechanisms of action. Issues related to the design and implementation of effective nutritional strategies are discussed, with a focus on unanswered questions on the most appropriate timing of nutritional interventions to preserve muscle health and function into old age. A brief description is also provided on new technologies that can facilitate the development and implementation of personalized nutrition plans to contrast sarcopenia.

Nutritional Interventions: Dietary Protein Needs and Influences on Skeletal Muscle of Older Adults

BACKGROUND

This narrative review describes foundational and emerging evidence of how dietary protein intakes may influence muscle-related attributes of older adults.

METHODS

PubMed was used to identify pertinent research.

RESULTS

Among medically stable older adults, protein intakes below the recommended dietary allowance (RDA) (0.8 g/kg body weight [BW]/d) exacerbate age-related reductions in muscle size, quality, and function. Dietary patterns with total protein intakes at or moderately above the RDA, including one or preferably more meals containing sufficient dietary protein to maximize protein anabolism, promote muscle size and function. Some observational studies suggest protein intakes from 1.0 to 1.6 g/kg BW/d may promote greater muscle strength and function more so than muscle size. Experimental findings from randomized controlled feeding trials indicate protein intakes greater than the RDA (averaging ~1.3 g/kg BW/d) do not influence indices of lean body mass or muscle and physical functions with non-stressed conditions, but positively influence changes in lean body mass with purposeful catabolic (energy restriction) or anabolic (resistance exercise training) stressors. Among older adults with diagnosed medical conditions or acute illness, specialized protein or amino acid supplements that stimulate muscle protein synthesis and improve protein nutritional status may attenuate the loss of muscle mass and function and improve survival of malnourished patients. Observational studies favor animal versus plant protein sources for sarcopenia-related parameters.

CONCLUSIONS

Quantity, quality, and patterning of dietary protein consumed by older adults with varied metabolic states, and hormonal and health status influence the nutritional needs and therapeutic use of protein to support muscle size and function.

Important Concepts in Protein Nutrition, Aging, and Skeletal Muscle: Honoring Dr Douglas Paddon-Jones (1969-2021) by Highlighting His Research Contributions

This review is a tribute to honor Dr Douglas Paddon-Jones by highlighting his career research contributions. Dr Paddon-Jones was a leader in recognizing the importance of muscle health and the interactions of physical activity and dietary protein for optimizing the health span. Aging is characterized by loss of muscle mass and strength associated with reduced rates of muscle protein synthesis (MPS) and the ability to repair and replace muscle proteins. Research from the team at the University of Texas Medical Branch in Galveston discovered that the age-related decline in MPS could be overcome by increasing the quantity or quality of dietary protein at each meal. Dr Paddon-Jones was instrumental in proposing and testing a "protein threshold" of ∼30 g protein/meal to optimize MPS in older adults. Dr Paddon-Jones demonstrated that physical inactivity greatly accelerates the loss of muscle mass and function in older adults. His work in physical activity led him to propose the "Catabolic Crisis Model" of muscle size and function losses, suggesting that age-related muscle loss is not a linear process, but the result of acute periods of disuse associated with injuries, illnesses, and bed rest. This model creates the opportunity to provide targeted interventions via protein supplementation and/or increased dietary protein through consuming high-quality animal-source foods. He illustrated that nutritional support, particularly enhanced protein quantity, quality, and meal distribution, can help preserve muscle health during periods of inactivity and promote health across the life course.

Improvement in chrono-nutrition is associated with robust weight loss outcomes: An extension of the feasibility study

Previously we had demonstrated the development and feasibility of an integrated chrono-nutrition weight reduction program among non-shift workers with morning and evening chronotypes. In this current paper, we described the association between the changes in chrono-nutrition practice and weight loss outcomes upon completing the weight reduction program. A total of 91 overweight/obese non-shift workers participated in the 12-week integrated chrono-nutrition weight reduction program (Age: 39.6 ± 6.3 y; 74.7% women; BMI: 31.2 ± 4.5 kg/m²). All the assessments including anthropometry, dietary, sleep habits, physical activity, and process of change were measured during pre- and post-intervention. Participants who had lost ≥3% of their body weight were categorized as satisfactory weight loss outcome, and those who did not achieve 3% weight loss were categorized as unsatisfactory weight loss. The satisfactory weight loss had greater daily percent energy intake during earlier in the day from protein (Mean difference (MD): +3.2%, 95% CI: 1.6, 4.9, p < .001) and smaller intake from fat during later in the day (MD: -2.6%, 95% CI: -5.1, -0.1, p = .045), earlier last mealtime (MD: -49.5 min, 95% CI: -86.5, -12.6, p = .009) and midpoint of eating (MD: -27.3 min, 95% CI: -46.3, -8.2, p = .006), shorter eating window (-0.8 h, 95% CI: -1.4, -0.1, p = .031) and greater reduction in night eating syndrome score (MD: -2.4, 95% CI: -4.3, -0.5, p = .015) compared to unsatisfactory weight loss outcome. After accounting for potential confounders, the temporal pattern of energy, protein, and fat intake were associated with greater odds of achieving a satisfactory weight loss. The findings suggest a promising role of chrono-nutrition as one of the strategies in weight reduction intervention.

Protein Intake in NCAA Division 1 Soccer Players: Assessment of Daily Amounts, Distribution Patterns, and Leucine Levels as a Quality Indicator

Dietary protein is required to support recovery and adaptation following exercise training. While prior research demonstrates that many athletes meet total daily protein needs, intake seems to be predominantly skewed toward the evening meal. An even distribution of protein doses of ≥0.24 g/kg BW consumed throughout the course of a day is theorized to confer greater skeletal muscle anabolism outcomes compared to a skewed pattern of intake. Protein quality is also an important dietary consideration for athletes, with the amino acid leucine seemingly serving as the primary driver of the postprandial anabolic response. The present study investigates protein consumption characteristics among a cohort of NCAA D1 soccer players and evaluates differences between male and female athletes. Athletes were instructed to complete 3-day food diaries, which were subsequently analyzed and compared to UEFA expert group-issued nutrition guidelines for soccer players. Breakfast, lunch, and dinner accounted for 81.4% of the total daily dietary protein intake. Most athletes (77.8%) ingested optimum amounts of protein at dinner but not at breakfast (11.1%) or lunch (47.2%). In addition, statistically significant sex-based differences in daily dietary protein intake, meal-specific protein amounts, and protein quality measures were detected. Findings indicate suboptimal dietary protein intake practices among the collegiate soccer athletes.

Public Health Need, Molecular Targets, and Opportunities for the Accelerated Development of Function-Promoting Therapies: Proceedings of a National Institute on Aging Workshop

Background

People ≥ 65 years are expected to live a substantial portion of their remaining lives with a limiting physical condition and the numbers of affected individuals will increase substantially due to the growth of the population of older adults worldwide. The age-related loss of muscle mass, strength, and function is associated with an increased risk of physical disabilities, falls, loss of independence, metabolic disorders, and mortality. The development of function-promoting therapies to prevent and treat age-related skeletal muscle functional limitations is a pressing public health problem.

Methods

On March 20–22, 2022, the National Institute on Aging (NIA) held a workshop entitled “Development of Function-Promoting Therapies: Public Health Need, Molecular Targets, and Drug Development.”

Results

The workshop covered a variety of topics including advances in muscle biology, novel candidate molecules, findings from randomized trials, and challenges in the design of clinical trials and regulatory approval of function-promoting therapies. Leading academic investigators, representatives from the National Institutes of Health (NIH) and the U.S. Food and Drug Administration (FDA), professional societies, pharmaceutical industry, and patient advocacy organizations shared research findings and identified research gaps and strategies to advance the development of function-promoting therapies. A diverse audience of 397 national and international professionals attended the conference.

Conclusions

Function-promoting therapies to prevent and treat physical disabilities associated with aging and chronic diseases are a public health imperative. Appropriately powered, well-designed clinical trials and synergistic collaboration among academic experts, patients and stakeholders, the NIH and the FDA, and the pharmaceutical industry are needed to accelerate the development of function-promoting therapies.

Muscle-Related Effect of Whey Protein and Vitamin D3 Supplementation Provided before or after Bedtime in Males Undergoing Resistance Training

There is increasing evidence that dietary protein intake with leucine and vitamin D is an important factor in muscle protein synthesis. This study investigated the combined effects of consuming whey protein and vitamin D₃ in the evening before bedtime or in the morning after sleeping on muscle mass and strength. Healthy, untrained males (N = 42; Age = 18-24 year) were randomly assigned into three groups: before bedtime, after sleeping, and control. Subjects underwent a 6-week resistance training program in combination with supplements that provided 25 g whey protein and 4000 IU vitamin D₃ for the before bedtime and after sleeping groups and a 5 g maltodextrin placebo for the control group. A significant increase in serum vitamin D was observed in both before bedtime and after sleeping groups. All groups experienced a significant gain in leg press. However, the control group did not experience significant improvements in muscle mass and associated blood hormones that were experienced by the before bedtime and after sleeping groups. No significant differences in assessed values were observed between the before bedtime and after sleeping groups. These findings suggest that the combination of whey protein and vitamin D supplements provided either before or after sleep resulted in beneficial increases in muscle mass in young males undergoing resistance training that exceeded the changes observed without these supplements.

Association of Dietary Protein Intake and Grip Strength Among Adults Aged 19+ Years: NHANES 2011–2014 Analysis

Background

Research on the role of protein in the diet has evolved beyond a focus on quantity to include the impact of its quality and distribution across meal times in an effort to optimize dietary protein recommendations.

Objective

To determine the association of dietary protein amount, type, and intake pattern with grip strength in adults.

Design

Data from the National Health and Nutrition Examination Survey (NHANES) 2011–2014 for adults 19 + years (N = 9,214) were used with exclusions for pregnant and lactating women. Intakes of dietary total protein (TP), animal protein (AP, including dairy), plant protein (PP), and leucine (Leu) were determined using day 1 24 h dietary recall data after adjusting for the complex sample design of NHANES. Regression analyses were used to assess the association of dietary protein and leucine intake quartiles, and whether consuming &gt; 20 g of dietary protein at one or more meals was related to grip strength with adjustment for age, gender, and ethnicity.

Results

Mean intake of TP among adults aged 19 + years was 83.6 ± 0.5 g/day, and 2/3rd of this was from animal sources (including dairy). Grip strength increased (p &lt; 0.05) with increasing quartiles of TP, AP, PP, and leucine among all adults 19 + years (β = 1.340.19, 1.27 ± 0.19, 0.76 ± 0.20, and 1.33 ± 0.23, respectively), 19–50 years (β = 1.14 ± 0.27, 1.06 ± 0.25, 0.77 ± 0.30, and 1.18 ± 0.27, respectively), and 51 + years (β = 0.95 ± 0.26, 1.08 ± 0.27, and 1.05 ± 0.27, respectively, for TP, AP, and Leu); however, the increase was more pronounced for AP than PP. Grip strength also increased (p &lt; 0.05) with increasing the number of meal occasions containing &gt; 20 g of dietary protein (β = 1.50 ± 0.20, 1.41 ± 0.25, and 0.91 ± 0.37 for 19+, 19–50, and 51 + years, respectively), and significant increases were detected for two meals compared to zero meals.

Conclusion

Dietary protein quantity, quality, and distribution should be considered collectively when looking to optimize protein intake to support muscle strength and function.

Increases in protein intake, protein distribution score, and micronutrient intakes in older adults in response to a whole food-based dietary intervention

BACKGROUND

Changes in nutrient intakes and protein distribution were analyzed in response to a whole food-based dietary intervention targeting high-protein meals in older adults.

METHODS

Community-dwelling older adults (n = 56; M/F, 28/28; age, 69.3 ± 4.0 years) completed a 12-week intervention after randomization to exercise only (EX, n = 19), nutrition only (NUTR, n = 16), or nutrition plus exercise (NUTR + EX, n = 21). NUTR and NUTR + EX followed a dietary intervention targeting ~ 0.4 g/kg of protein at each of breakfast, lunch and dinner.

RESULTS

Relative protein intake increased in NUTR (0.99 ± 0.34 to 1.43 ± 0.39 g/kg, P < 0.001) and NUTR + EX (0.90 ± 0.20 to 1.57 ± 0.49 g/kg, P < 0.001). Intakes of cholesterol, B vitamins, selenium and iodine were increased in both NUTR and NUTR + EX (P < 0.05 for all).

CONCLUSION

This dietary intervention was effective at increasing daily protein intake and achieving an even distribution pattern. Changes in micronutrient intake were marked, and reflect the increase in consumption of animal-derived protein-rich food sources.

Older American Women May Especially Benefit from Distributing and Consuming Protein for Decreasing Odds of Functional Limitations

OBJECTIVES

Protein is a key macronutrient for preserving physical function, but the role of protein intake on functional status may differ in men and women. We sought to examine the associations of daily protein intake and distribution on functional limitations in older American men and women.

DESIGN

Cross-sectional.

SETTING

Population-based survey.

PARTICIPANTS

The analytic sample included 3,976 men and 4,081 women aged ≥60-years from the 2007-2016 waves of the National Health and Nutrition Examination Survey.

MEASUREMENTS

Participants reported their ability to perform basic activities of daily living, instrumental activities of daily living, leisure and social activities, lower extremity mobility activities, and general physical tasks. Those reporting difficulty or an inability in completing such functional tasks were considered as having a functional limitation. Protein intake was determined with dietary recalls and participants revealed functional limitations. Protein recommendations of ≥0.80, ≥1.00, and ≥1.50 g/kg/day were used. Based on these cut-points, we also investigated distribution of protein across 4 eating occasions at ≥0.20, ≥0.25, and ≥0.38 g/kg/meal, respectively.

RESULTS

Older women meeting each recommendation had decreased odds for functional limitations: 0.55 (95% confidence interval (CI): 0.40-0.75) for ≥0.80 g/kg/day, 0.75 (CI: 0.58-0.97) for ≥1.00 g/kg/day, and 0.72 (CI: 0.55-0.94) for ≥1.5 g/kg/day. No significant associations were observed in older men. Further, older women with protein consumption ≥0.20 g/kg/meal had decreased odds for functional limitations: 0.24 (CI: 0.10-0.61) for 1 occasion, 0.20 (CI: 0.08-0.49) for 2 occasions, 0.16 (CI: 0.07-0.40) for 3 occasions, and 0.12 (CI: 0.04-0.32) for 4 occasions. A similar trend was observed for intake ≥0.25 g/kg/meal: 0.31 (CI: 0.16-0.62) for 2 occasions, 0.30 (CI: 0.14-0.61) for 3 occasions, and 0.31 (CI: 0.12-0.78) for 4 occasions. Women with 1 and 2 eating occasions at ≥0.38 g/kg/meal of protein had 0.66 (CI: 0.48-0.91) and 0.54 (CI: 0.37-0.79) decreased odds for functional limitations, respectively.

CONCLUSION

Trials that are powered to detect the effects of protein on functional status in women will help to establish causality.

Strategies to Prevent Sarcopenia in the Aging Process: Role of Protein Intake and Exercise

Sarcopenia is one of the main issues associated with the process of aging. Characterized by muscle mass loss, it is triggered by several conditions, including sedentary habits and negative net protein balance. According to World Health Organization, it is expected a 38% increase in older individuals by 2025. Therefore, it is noteworthy to establish recommendations to prevent sarcopenia and several events and comorbidities associated with this health issue condition. In this review, we discuss the role of these factors, prevention strategies, and recommendations, with a focus on protein intake and exercise.

A muscle-centric view of time-restricted feeding for older adults

PURPOSE OF REVIEW

The practice of time-restricted feeding (TRF) has received fervent interest in recent years as a strategy to mitigate obesity and metabolic disease. We sought to review the implications of TRF for skeletal muscle health and function in aging.

RECENT FINDINGS

TRF has high adherence and can promote body weight loss in older populations. Body weight reductions favor fat mass in the young, however, there is also the potential for undesirable losses in lean mass. There is currently no evidence to support TRF for skeletal muscle function and metabolism in older persons, and only tentative findings in the young. With a narrow eating window of 6-8 h and a prolonged fasting period to minimize daily insulin exposure, TRF may contradict recommended dietary practices for optimizing skeletal muscle anabolism in older people.

SUMMARY

TRF might represent a promising intervention to address obesity and its associated metabolic diseases, however, at present there is insufficient evidence for optimizing skeletal muscle mass or health in older individuals. Further research is needed to: (1) ascertain the impact of TRF on body composition, skeletal muscle anabolism, and autophagy in aging, and; (2) delineate the potentially myoprotective roles of dietary protein and exercise within the framework of TRF in older persons.

Protein Requirements for Master Athletes: Just Older Versions of Their Younger Selves

It is established that protein requirements are elevated in athletes to support their training and post-exercise recovery and adaptation, especially within skeletal muscle. However, research on the requirements for this macronutrient has been performed almost exclusively in younger athletes, which may complicate their translation to the growing population of Master athletes (i.e. > 35 years old). In contrast to older (> 65 years) untrained adults who typically demonstrate anabolic resistance to dietary protein as a primary mediator of the ‘normal’ age-related loss of muscle mass and strength, Master athletes are generally considered successful models of aging as evidenced by possessing similar body composition, muscle mass, and aerobic fitness as untrained adults more than half their age. The primary physiology changes considered to underpin the anabolic resistance of aging are precipitated or exacerbated by physical inactivity, which has led to higher protein recommendations to stimulate muscle protein synthesis in older untrained compared to younger untrained adults. This review puts forth the argument that Master athletes have similar muscle characteristics, physiological responses to exercise, and protein metabolism as young athletes and, therefore, are unlikely to have protein requirements that are different from their young contemporaries. Recommendations for protein amount, type, and pattern will be discussed for Master athletes to enhance their recovery from and adaptation to resistance and endurance training.

Usual Protein Intake Amount and Sources of Nursing Home Residents with (Risk of) Malnutrition and Effects of an Individualized Nutritional Intervention: An enable Study

Nursing home (NH) residents with (risk of) malnutrition are at particular risk of low protein intake (PI). The aim of the present analysis was (1) to characterize usual PI (total amount/day (d) and meal, sources/d and meal) of NH residents with (risk of) malnutrition and (2) to evaluate the effects of an individualized nutritional intervention on usual PI. Forty residents (75% female, 85 ± 8 years) with (risk of) malnutrition and inadequate dietary intake received 6 weeks of usual care followed by 6 weeks of intervention. During the intervention phase, an additional 29 ± 11 g/d from a protein-energy drink and/or 2 protein creams were offered to compensate for individual energy and/or protein deficiencies. PI was assessed with two 3-day-weighing records in each phase and assigned to 4 meals and 12 sources. During the usual care phase, mean PI was 41 ± 10 g/d. Lunch and dinner contributed 31 ± 11% and 32 ± 9% to daily intake, respectively. Dairy products (median 9 (interquartile range 6–14) g/d), starchy foods (7 (5–10) g/d) and meat/meat products (6 (3–9) g/d) were the main protein sources in usual PI. During the intervention phase, an additional 18 ± 10 g/d were consumed. Daily PI from usual sources did not differ between usual care and intervention phase (41 ± 10 g/d vs. 42 ± 11 g/d, p = 0.434). In conclusion, daily and per meal PI were very low in NH residents with (risk of) malnutrition, highlighting the importance of adequate intervention strategies. An individualized intervention successfully increased PI without affecting protein intake from usual sources.

Pre-Sleep Casein Supplementation, Metabolism, and Appetite: A Systematic Review

Protein intake is an important factor for augmenting the response to resistance training in healthy individuals. Although food intake can help with anabolism during the day, the period of time during sleep is typically characterized by catabolism and other metabolic shifts. Research on the application of nighttime casein protein supplementation has introduced a new research paradigm related to protein timing. Pre-sleep casein supplementation has been attributed to improved adaptive response by skeletal muscle to resistance training through increases in muscle protein synthesis, muscle mass, and strength. However, it remains unclear what the effect of this nutritional strategy is on non-muscular parameters such as metabolism and appetite in both healthy and unhealthy populations. The purpose of this systematic review is to understand the effects of pre-sleep casein protein on energy expenditure, lipolysis, appetite, and food intake in both healthy and overweight or obese individuals. A systematic review following PRISMA guidelines was conducted in CINAHL, Cochrane, and SPORTDiscus during March 2021, and 11 studies met the inclusion criteria. A summary of the main findings shows limited to no effects on metabolism or appetite when ingesting 24-48 g of casein 30 min before sleep, but data are limited, and future research is needed to clarify the relationships observed.

Indicators and Recommendations for Assessing Sustainable Healthy Diets

Research coupling human nutrition and sustainability concerns is a rapidly developing field, which is essential to guide governments' policies. This critical and comprehensive review analyzes indicators and approaches to "sustainable healthy diets" published in the literature since this discipline's emergence a few years ago, identifying robust gauges and highlighting the flaws of the most commonly used models. The reviewed studies largely focus on one or two domains such as greenhouse gas emissions or water use, while overlooking potential impact shifts to other sectors or resources. The present study covers a comprehensive set of indicators from the health, environmental and socio-economic viewpoints. This assessment concludes that in order to identify the best food option in sustainability assessments and nutrition analysis of diets, some aspects such as the classification and disaggregation of food groups, the impacts of the rates of local food consumption and seasonality, preservation methods, agrobiodiversity and organic food and different production systems, together with consequences for low-income countries, require further analysis and consideration.

High Frequency Protein-Rich Meal Service to Promote Protein Distribution to Stimulate Muscle Function in Preoperative Patients

Apart from meeting daily protein requirements, an even distribution of protein consumption is proposed instrumental to optimizing protein muscle synthesis and preserving muscle mass. We assessed whether a high frequency protein-rich meal service for three weeks contributes to an even daily protein distribution and a higher muscle function in pre-operative patients. This study was a post-hoc analysis of a randomized controlled trial (RCT) in 102 patients. The intervention comprised six protein-rich dishes per day. Daily protein distribution was evaluated by a three-day food diary and muscle function by handgrip strength before and after the intervention. Protein intake was significantly higher in the intervention group at the in-between meals in the morning (7 ± 2 grams (g) vs. 2 ± 3 g, p < 0.05) and afternoon (8 ± 3 g vs. 2 ± 3 g, p < 0.05). Participants who consumed 20 g protein for at least two meals had a significantly higher handgrip strength compared to participants who did not. A high frequency protein-rich meal service is an effective strategy to optimize an even protein distribution across meals throughout the day. Home-delivered meal services can be optimized by offering more protein-rich options such as dairy or protein supplementation at breakfast, lunch and prior to sleep for a better protein distribution.

Evenness of dietary protein distribution is associated with higher muscle mass but not muscle strength or protein turnover in healthy adults: a systematic review

PURPOSE

Age-related decrease in muscle mass is, among several other factors, caused by suboptimal dietary protein intake. The protein intake of the general population has a skewed distribution towards the evening meal. However, it is hypothesised that an intake of protein with an even meal distribution leads to a more frequently maximised protein synthesis. This review investigates whether an even protein distribution is associated with preservation or gain in muscle mass, muscle strength, and protein turnover.

METHODS

Seven databases: PubMed, Web of Science, Google Scholar, CINAHL, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Embase were searched. Studies included had a healthy population between 20 and 85 years of age, with a BMI between 18.5 and 30.0, investigated even vs. skewed protein distribution, and measured skeletal muscle relevant outcomes. Case studies and systematic reviews were excluded. Studies were appraised using the AXIS scale for observational studies and the PEDro scale for the remaining studies.

RESULTS

Fifteen studies met the eligibility criteria and were included. Three out of seven studies showed an association between even protein distribution and higher muscle mass. Two out of seven studies showed an association between greater muscle strength and an even protein distribution. Only one out of six studies found a positive association between protein synthesis and an even protein distribution.

CONCLUSION

Evidence indicated an association between muscle mass and an even protein intake. However, the evidence is currently insufficient to conclude whether an even protein intake is positively associated with muscle strength or protein turnover.

Joint position statement on management of patient with osteoporosis during COVID-19 contingency from the AMMOM, CONAMEGER, FELAEN, FEMECOG, FEMECOT, and ICAAFYD

Infection by SARS-Cov-2 (COVID-19) has affected practically all the world. This joint position statement of Latin American Medical Societies provides an updated guide for the prevention, diagnosis, and treatment of osteoporotic patients in the face of possible clinical scenarios posed by the COVID-19 health crisis.

BACKGROUND

Infection by SARS-Cov-2 (COVID-19) has affected practically all the world. Characterized by high contagiousness, significative morbidity, and mortality in a segment of those infected, it has overwhelmed health services and forced to redirect resources to the emergency while impacting the attention of acute non-COVID-19 and many chronic conditions.

OBJECTIVE

The objective of this study is to provide an updated guide for the prevention, diagnosis, and treatment of osteoporotic patients in the face of possible clinical scenarios posed by the COVID-19 health crisis.

METHODS

A task force, of bone specialists with a wide range of disciplines in the field of osteoporosis and fragility fracture, was convened with the representation of several professional associations, namely, the Mexican Association of Bone and Mineral Metabolism (AMMOM), the National College of Geriatric Medicine (CONAMEGER), the Latin American Federation of Endocrinology (FELAEN), the Mexican Federation of Colleges of Obstetrics and Gynecology (FEMECOG), the Mexican Federation of Colleges of Orthopedics and Traumatology (FEMECOT), and the Institute of Applied Sciences for Physical Activity and Sports of the University of Guadalajara (ICAAFYD). Clinical evidence was collated, and an evidence report was rapidly generated and disseminated. After finding the gaps in the available evidence, a consensus opinion of experts was made. The resulting draft was reviewed and modified accordingly, in 4 rounds, by the participants.

RESULTS

The task force approved the initial guidance statements, with moderate and high consensus. These were combined, resulting in the final guidance statements on the (1) evaluation of fracture risk; (2) stratification of risk priorities; (3) indications of bone density scans and lab tests; (4) initiation and continuation of pharmacologic therapy; (5) interruptions of therapy; (6) treatment of patients with incident fracture; (7) physical therapy and fall prevention; and (8) nutritional interventions.

CONCLUSION

These guidance statements are provided to promote optimal care to patients at risk for osteoporosis and fracture, during the current COVID-19 pandemic. However, given the low level of available evidence and the rapidly evolving literature, this guidance is presented as a "living document" and future updates are anticipated.

Dietary Protein Intake Patterns and Inadequate Protein Intake in Older Adults from Four Countries

Recent interest in protein intake per meal is observed in studies that have reported the protein intake patterns in different countries; however, comparisons of these data are lacking. We aimed to compare protein intake patterns and the percentage of inadequate protein intake (IPI) per day and meal in older adults from different countries. We acquired data of protein intake in older adults from four countries (Mexico, United States of America, Germany, and United Kingdom). We compared protein intake (per day and meal), IPI per day and meal, and the number of meals with an adequate protein content among countries. The IPI per day significantly differed among countries for <0.8 and <1.0 (both p < 0.001), but not for <1.2 g/kg/d (p = 0.135). IPI per meal (<30 g/meal) did not differ among countries at breakfast (p = 0.287) and lunch (p = 0.076) but did differ at dinner (p < 0.001). Conversely, IPI per meal (<0.4 g/kg/meal) significantly differed among countries at breakfast, lunch, and dinner (all p < 0.001). The percentage of participants that ate ≥30 g/meal or ≥0.4 g/kg/meal at zero, one, and two or three meals per day significantly differed among countries (all p < 0.05). IPI at breakfast and lunch (<30 g/meal) was a common trait in the analyzed samples and might represent an opportunity for nutritional interventions in older adults in different countries.

Daily Protein and Energy Intake Are Not Associated with Muscle Mass and Physical Function in Healthy Older Individuals-A Cross-Sectional Study

Dietary protein has a pivotal role in muscle mass maintenance with advancing age. However, an optimal dose and distribution of protein intake across the day as well as the interaction with energy intake for the maintenance of muscle mass and physical function in healthy older adults remain to be fully elucidated. The purpose of this study was to examine the association between muscle mass, strength, and physical function, and the total amount and distribution of protein and energy intake across the day in healthy older individuals. The research question was addressed in a cross-sectional study including 184 Danish men and woman (age: 70.2 ± 3.9 years, body mass: 74.9 ± 12.1 kg, Body Mass Index (BMI): 25.4 ± 3.7 kg/m²) where a 3-day dietary registration, muscle mass, strength, and functional measurements were collected. We found that neither daily total protein intake nor distribution throughout the day were associated with muscle mass, strength, or physical function. Consequently, we do not provide an incentive for healthy older Danish individuals who already adhere to the current internationally accepted recommended dietary protein intake (0.83 g/kg/day) to change dietary protein intake or its distribution pattern throughout the day.

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.