Amount, Distribution, and Quality of Protein Intake Are Not Associated with Muscle Mass, Strength, and Power in Healthy Older Adults without Functional Limitations-An enable Study

Nutritional approaches targeting mitochondria for the prevention of sarcopenia

A decline in function and loss of mass, a condition known as sarcopenia, is observed in the skeletal muscles with aging. Sarcopenia has a negative effect on the quality of life of elderly. Individuals with sarcopenia are at particular risk for adverse outcomes, such as reduced mobility, fall-related injuries, and type 2 diabetes mellitus. Although the pathogenesis of sarcopenia is multifaceted, mitochondrial dysfunction is regarded as a major contributor for muscle aging. Hence, the development of preventive and therapeutic strategies to improve mitochondrial function during aging is imperative for sarcopenia treatment. However, effective and specific drugs that can be used for the treatment are not yet approved. Instead studies on the relationship between food intake and muscle aging have suggested that nutritional intake or dietary control could be an alternative approach for the amelioration of muscle aging. This narrative review approaches various nutritional components and diets as a treatment for sarcopenia by modulating mitochondrial homeostasis and improving mitochondria. Age-related changes in mitochondrial function and the molecular mechanisms that help improve mitochondrial homeostasis are discussed, and the nutritional components and diet that modulate these molecular mechanisms are addressed.

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.

Association of dietary protein intake, inflammation with muscle mass, physical performance and incident sarcopenia in Chinese community-dwelling older adults

OBJECTIVES

Inflammation and impaired muscle synthesis are important factors of sarcopenia. Plant protein may reduce inflammation but may not be as efficient as animal protein in providing essential amino acids. We therefore examined the associations between dietary protein intake and changes in muscle mass and physical performance, incident sarcopenia, and the interaction effect of inflammation.

DESIGN

Prospective cohort study.

SETTING

The Mr. OS and Ms. OS (Hong Kong) cohort.

PARTICIPANTS

A total of 2,811 sarcopenia-free participants and 569 sarcopenia participants aged ≥65 years were recruited from communities.

MEASUREMENTS

Dietary protein intake was assessed using a validated food frequency questionnaire. Serum high-sensitivity C-reactive protein (hs-CRP) was measured. Linear regression examined the associations between dietary protein intake and 4-year changes in muscle mass and physical performance. Cox regression examined the association between dietary protein intake and incident sarcopenia.

RESULTS

Higher plant protein intake, but not total and animal protein, was associated with less decline in muscle mass and gait speed among sarcopenia-free participants. Conversely, higher ratio of animal-to-plant protein was associated with reduced muscle mass loss among participants with sarcopenia. The highest tertile of plant protein intake was associated with lower incident sarcopenia risk (HR: 0.75, 95% CI: 0.57-0.98; P-trend = 0.034) compared to the lowest tertile. Notably, this association was observed among participants with higher serum hs-CRP levels (HR: 0.57, 95% CI: 0.34-0.95), but not in those with lower hs-CRP levels.

CONCLUSION

Dietary animal and plant protein intake have differential associations with muscle mass and physical performance in older adults with and without sarcopenia. The role of plant protein in preventing sarcopenia involves modulation of inflammation.

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.

Associations of protein intake, sources and distribution on muscle strength in community-dwelling older adults living in Auckland, New Zealand

Protein intake, sources and distribution impact on muscle protein synthesis and muscle mass in older adults. However, it is less clear whether dietary protein influences muscle strength. Data were obtained from the Researching Eating Activity and Cognitive Health (REACH) study, a cross-sectional study aimed at investigating dietary patterns, cognitive function and metabolic syndrome in older adults aged 65-74 years. Dietary intake was assessed using a 4-d food record and muscle strength using a handgrip strength dynamometer. After adjusting for confounders, in female older adults (n 212), total protein intake (β = 0⋅22, P < 0⋅01); protein from dairy and eggs (β = 0⋅21, P = 0⋅03) and plant food sources (β = 0⋅60, P < 0⋅01); and frequently consuming at least 0⋅4 g/kg BW per meal (β = 0⋅08, P < 0⋅01) were associated with higher BMI-adjusted muscle strength. However, protein from meat and fish intake and the coefficient of variance of protein intake were not related to BMI-muscle strength in female older adults. No statistically significant associations were observed in male participants (n = 113). There may be sex differences when investigating associations between protein intake and muscle strength in older adults. Further research is needed to investigate these sex differences.

Protein and Leucine Intake at Main Meals in Elderly People with Type 2 Diabetes

Background: The recommended protein intake for the elderly is 25–30 g at main meals, with at least 2500–2800 mg of leucine at each meal. There is still little evidence regarding the amount and distribution of protein and leucine intake with meals in the elderly with type 2 diabetes (T2D). In this cross-sectional study, we evaluated protein and leucine intake at each meal in elderly patients with T2D. Methods: A total of 138 patients (91 men and 47 women) with T2D, aged 65 years or older, were included. Participants performed three 24-h dietary recalls for the evaluation of their dietary habits and protein and leucine intake at meals. Results: The average protein intake was 0.9 ± 0.2 g/kg body weight/day, and only 23% of patients complied with the recommendations. The average protein intake was 6.9 g at breakfast, 29 g at lunch, and 21 g at dinner. None of the patients reached the recommended protein intake at breakfast; 59% of patients complied with the recommendations at lunch; and 32% at dinner. The average leucine intake was 579 mg at breakfast, 2195 g at lunch, and 1583 mg at dinner. The recommended leucine intake was not reached by any patient at breakfast, by 29% of patients at lunch, and by 13% at dinner. Conclusions: Our data show that, in elderly patients with T2D, the average protein intake is low, particularly at breakfast and dinner, and that leucine intake is remarkably lower than the recommended levels. These data raise the need to implement nutritional strategies capable of increasing protein and leucine intake in the elderly with T2D.

Validation of the German version of the Protein Screener 55

BACKGROUND/OBJECTIVES

The Protein Screener 55 + (Pro55 + ) is a brief food questionnaire to screen older community-dwelling adults for low protein intake. The result is the predicted probability of protein intake <1.0 g/kg adjusted body weight (aBW)/d ranging from 0-1. For purposes of cross-cultural validation, we translated the Pro55+ into German and tested its discriminative accuracy in detecting low protein intake of older community-dwelling people in Germany.

SUBJECTS/METHODS

After translation and pilot-testing, the Pro55+ and the reference standard (3-day dietary record) were completed by 144 participants (81.6 ± 3.9 years, 61.8% female). Discriminative properties were tested by receiver operating characteristic curves and by calculating sensitivity and specificity for different cut-offs of predicted probability (>0.3/>0.5/>0.7) using <1.0 or <0.8 g/kg aBW/d to define low protein intake.

RESULTS

Protein intake was <1.0 g/kg aBW/d in 39.6% of the sample and <0.8 g/kg aBW/d in 17.4%. Area under the curve was 62.0% (95%CI 52.6-71.5) and 68.8% (58.1-79.4), respectively. Specificity was 82-90% using probability cut-offs of 0.5 and 0.7 for both protein thresholds. Sensitivity was poor for protein threshold of 1.0 g/kg aBW/d regardless of the used probability cut-offs. For protein threshold of <0.8 g/kg aBW/d, sensitivity was 88.0% (71.8-96.9) using a probability cut-off of 0.09.

CONCLUSION

The overall discriminative accuracy of the German Pro55+ to identify older community-dwelling people with low protein intake was poor. However, applying different probability cut-offs allows increasing specificity and sensitivity for 0.8 g/kg aBW/d to levels justifying the use for certain purposes e.g. excluding individuals with adequate protein intake. Further validation is needed.

Lower-Limb Muscle Power Is Negatively Associated with Protein Intake in Older Adults: A Cross-Sectional Study

The present study examined the association between lower-limb muscle power and protein-related parameters in older adults. This study followed a cross-sectional design. Participants were community-dwelling older adults. Candidates were considered eligible if they were 60 years or older, lived independently, and possessed sufficient physical and cognitive abilities to perform all the measurements required by the protocol. The 5 times sit-to-stand (5STS) test was performed as fast as possible according to a standard protocol. Absolute, relative, and allometric muscle power measures were estimated using 5STS-based equations. Diet was assessed by 24-h dietary recall and diet composition was estimated using a nutritional software. One-hundred and ninety-seven older adults participated to the present study. After adjustment for covariates, absolute and allometric muscle power were negatively associated with body weight-adjusted protein intake. Our findings indicate that absolute and allometric muscle power estimated through a simple equation are negatively associated with body weight-adjusted protein intake in community-dwelling older adults.

Protein intake and physical function in older adults: A systematic review and meta-analysis

BACKGROUND

The present study explored cross-sectional and longitudinal associations between protein intake and physical function in older adults.

METHODS

We conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated the association between protein intake and measures of physical function in older adults. Cross-sectional, case-control, and longitudinal cohort studies that investigated the association between protein intake and physical function as a primary or secondary outcome in people aged 60 + years were included. Studies published in languages other than English, Italian, Portuguese, or Spanish were excluded. Studies were retrieved from MEDLINE, SCOPUS, EMBASE, CINAHL, AgeLine, and Food Science Source databases through January 31, 2022. A pooled effect size was calculated based on standard mean differences (SMD), MD, log odds ratio (OR) and Z-score..

RESULTS

Twenty-two cross-sectional studies examined a total of 11,332 community-dwellers, hospitalized older adults, and elite senior athletes with a mean age of approximately 75 years. The pooled analysis indicated that a protein intake higher than the recommended dietary allowance (RDA) was significantly associated with higher Short Physical Performance Battery (SPPB) scores (SMD: 0.63, 95% CI: 0.27, 0.99, P-value: 0.0006), faster walking speed, greater lower-limb (SMD: 0.22, 95% CI: 0.04, 0.40, P-value: 0.02) and isometric handgrip strength (Z-score: 0.087, 95% CI: 0.046-0.128, P-value: 0.0001), and better balance (SMD: 0.33, 95% CI: 0.05, 0.62, P-value: 0.02). Nine longitudinal studies investigated 12,424 community-dwelling and native older adults with a mean age of approximately 85 years. A protein intake higher than the current RDA was not associated with lower decline in either isometric handgrip strength (logOR: 0.99, 95% CI: 0.97-1.02, P-value= 0.67) or walking speed (logOR: 0.92, 95% CI: 0.77-1.10, P-value= 0.35).

CONCLUSIONS

A protein intake higher than the RDA is cross-sectionally associated with better physical performance and greater muscle strength in older adults. However, a high consumption of proteins does not seem to prevent physical function decline over time.

Evenness of Dietary Protein Intake Is Positively Associated with Lean Mass and Strength in Healthy Women

Background:

Evenness of protein intake is associated with increased lean mass, but its relationship with muscle strength and performance is uncertain.

Objectives:

We determined the association of evenness of protein intake with lean mass, muscle strength and endurance, and functional ability.

Design:

This was a cross-sectional study.

Setting:

Data were collected at a research university in the upper midwestern United States.

Participants:

One hundred ninety-two healthy women, aged 18 to 79 years, mean ± SEM 41.9 ± 1.3, completed the study.

Measurements:

Dietary intake was assessed using 3-day food diaries verified with food frequency questionnaires. To assess evenness of protein intake, the day was divided into 3 periods: waking to 11:30, 11:31 to 16:30, and after 16:30. Lean mass was measured with dual energy X-ray absorptiometry. Lower-body muscle strength and endurance were determined using isokinetic dynamometry. Upper-body muscle strength was maximal handgrip strength. Functional ability was assessed using 6-m gait speed and 30-second chair stand tests. Accelerometry measured physical activity.

Results:

Intakes of 25 g or more of protein at 1 or more of the 3 periods was positively associated with lean mass (β ± S.E.; 1.067 ± 0.273 kg, P < .001) and upper-body (3.274 ± 0.737 kg, P < .001) and lower-body strength (22.858 ± 7.918 Nm, P = .004) when controlling for age, body mass index, physical activity, and energy and protein intakes. Consuming at least 0.24 g/kg/period for those under 60 years and 0.4 g/kg/period for those 60 years and older was related to lean mass (0.754 ± 0.244 kg, P = .002), upper-body strength (2.451 ± 0.658 kg, P < .001), and lower-body endurance (184.852 ± 77.185 J, P = .018), controlling for the same variables.

Conclusions:

Evenness of protein intake is related to lean mass, muscle strength, and muscular endurance in women. Spreading protein intake throughout the day maximizes the anabolic response to dietary protein, benefiting muscle mass and performance.

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 with skeletal muscle mass in older adults: A systematic review

Protein supplementation has been shown to be effective in attenuating the loss of lean body mass and muscle mass in older adults; however, its benefits as dietary protein remain unclear. This systematic review of observational studies aimed to investigate the association of dietary protein intake with skeletal muscle mass (SM). Observational studies that investigated the association of dietary protein intake with SM in older adults were retrieved from MEDLINE, Web of Science and Cochrane-CENTRAL databases. Of the 26 analyses in the 17 studies, 18 showed a significant positive association. In cohort studies, 55.6% (five of nine analyses) showed a significant positive association. Of these, four analyses were adjusted for well-known confounding factors, used energy-adjusted protein intake, and used the amount of change of SM between baseline and follow-up as the outcome, with two of them showing a significant positive association. Although 69.2% (18 of 26 analyses) of the 17 studies showed a significant positive association between dietary protein intake and SM in older adults, most studies were cross-sectional and had at least one important methodological limitation. Therefore, we could not draw any conclusions. Thus, well-designed cohort studies are needed in future to identify the association between dietary protein intake and SM in older adults. Geriatr Gerontol Int 2021; 21: 1077-1083.

Association between meal-specific daily protein intake and lean mass in older adults: results of the cross-sectional BASE-II study

BACKGROUND

Adequate total and meal-specific protein intake is considered an important prerequisite to preserve appendicular lean mass (ALM) in older adults and to prevent sarcopenia.

OBJECTIVES

We analyzed the meal-specific protein intake across the main meals between participants with normal vs. low ALM to BMI ratio (ALMBMI).

METHODS

782 participants [59.6% men; median 69 (IQR: 65, 71) y] of the Berlin Aging Study II have been included in this analysis. ALM was assessed by dual X-ray absorptiometry. Low lean mass was defined as ALMBMI using recommended sex-specific cut-offs. A 5-day nutritional protocol was used to assess total and meal-specific protein intake.

RESULTS

Median total protein intake was 0.89 (IQR: 0.74, 1.05) g/kg/d body weight (BW) in participants with low ALMBMI and 1.02 (IQR: 0.86, 1.21) g/kg BW in participants with normal ALMBMI (P < 0.001). Daily protein intake at breakfast was similar in both groups [0.23 (95% CI: 0.20, 0.26) vs. 0.24 (95% CI: 0.23, 0.26) g/kg BW; P = 0.245]. Subjects with low ALMBMI reported a lower protein intake at lunch and dinner compared with those with normal ALMBMI [0.29 (95% CI: 0.27, 0.32) vs. 0.35 (95% CI: 0.34, 0.36) g/kg BW; P = 0.001 and 0.32 (95% CI: 0.30, 0.35) vs. 0.36 (95% CI: 0.35, 0.37) g/kg BW; P = 0.027, respectively]. In a stepwise regression model, a higher total protein intake was positively associated with ALMBMI [ß = 0.10 (95% CI: 0.07, 0.13) P < 0.001]. The protein intake at dinner was positively associated with ALMBMI [ß = 0.14 (95% CI: 0.08, 0.19) P < 0.001] irrespective of protein intake at breakfast and lunch. This association disappeared after additional adjustment for total protein intake.

CONCLUSION

Our data highlight an association of total protein intake and ALMBMI in older adults. Although current data support an association of high ALMBMI with protein intake at dinner in particular, this was not independent from total protein intake and the findings do not allow a conclusion on causality.

Personalized Protein Supplementation Improves Total Protein, Leucine, and Energy Intake in (Pre)Sarcopenic Community-Dwelling Older Adults in the ENHANce RCT

Recommendations concerning protein quantity, source, and leucine intake for older adults are difficult to reach by regular dietary intake. This randomized clinical trial assesses in sarcopenic community-dwelling older adults (i) the regular (non-supplemented) daily protein and leucine intake; and (ii) the effect of personalized protein supplementation (aiming for an evenly distributed total protein intake of 1.5 g·kg^-1·d^-1 of body mass, accounting for energy intake) on regular and total (dietary and supplemental) intake. A preliminary feasibility study in participants of the ongoing Exercise and Nutrition for Healthy AgeiNg (ENHANce) study was performed with the objective to assess the intake and distribution of regular dietary protein and leucine, protein source and energy intake in (pre)sarcopenic community-dwelling older adults. Moreover, this study aimed to assess if personalized protein supplementation was feasible without negatively affecting regular dietary intake. ENHANce (NCT03649698) is a 5-armed RCT that assesses the effect of anabolic interventions on physical performance in (pre)sarcopenic older adults. In August 2019, n = 51 participants were included in ENHANce with complete available data on dietary intake at screening and thus eligible for inclusion in present analysis. Of these, n = 35 participants completed the intervention period of ENHANce at the moment of analysis, allowing an exploration of the effect of supplementation on regular dietary intake. The regular dietary protein intake of 51 (pre)sarcopenic adults (73.6 ± 6.5 years) was 1.06 ± 0.3 g·kg^-1·d^-1 of body mass. Protein supplementation (n = 20) improved total protein intake to 1.55 ± 0.3 g·kg^-1·d^-1 of body mass (P < 0.001) without affecting regular dietary protein (P = 0.176) or energy intake (P = 0.167). Placebo supplementation (n = 15) did not affect regular dietary protein intake (P = 0.910) but decreased regular dietary energy intake (P = 0.047). Regular leucine intake was unevenly distributed over the day, but increased by supplementation at breakfast (P < 0.001) and dinner (P = 0.010) to at least 2.46 g leucine·meal^-1, without reducing regular dietary leucine intake (P = 0.103). Animal-based protein intake-the main protein source-was not affected by supplementation (P = 0.358). Personalized protein supplementation ensured an adequate quantity and even distribution of protein and leucine over the day, without affecting regular dietary protein or energy intake.

Adequate protein intake in older adults in the context of frailty: cross-sectional results of the Nutrition and Health Survey in Taiwan 2014-2017

BACKGROUND

Emerging evidence suggests that a dietary protein intake higher than the current recommended dietary allowance of 0.8 g/kg body weight (BW)/d may be needed to maintain optimal muscle mass, strength, and function in older adults. However, defining optimal protein intake in this age group remains a challenge.

OBJECTIVE

In this study we sought to describe the dietary protein intake in frail, prefrail, and robust older Taiwanese adults.

METHODS

Data for 1920 older adults were collected from the Nutrition and Health Survey in Taiwan from 2014 to 2017. Dietary intake was assessed using the 24-h recall method. Frailty was determined using the modified Fried's criteria. Body composition was assessed using DXA. Sex-specific dietary protein intakes, measured as values/kg of BW, fat-free mass (FFM), and lean mass (LM), were estimated for the 3 age groups (65-69, 70-79, and ≥80y) and the 3 frailty levels.

RESULTS

In both males (P for trend = 0.034) and females (P for trend = 0.015), there were significant downward trends for protein intake/kg of BW with the severity of frailty. The age-adjusted protein intake/kg of BW was still significant in males (P for trend = 0.009), but no longer in females. This phenomenon was also seen for protein intake at lunch and dinner but not at breakfast. Age-adjusted trends for protein intake/kg FFM or LM were not significant in either sex. The median protein intake in robust older males and females was 1.21 and 1.19 g/kg BW/d, respectively, and the mean intakes were even higher.

CONCLUSION

Median protein intake in robust Taiwanese older adults was approximately 1.2 g/kg BW/d, with higher mean values. The protein adequate intake in Taiwanese older adults was higher than the current recommended daily allowance (RDA) level but within the RDA range derived from the state-of art indicator amino acid oxidation technique.

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.

The Effects of a High-Protein Dairy Milk Beverage With or Without Progressive Resistance Training on Fat-Free Mass, Skeletal Muscle Strength and Power, and Functional Performance in Healthy Active Older Adults: A 12-Week Randomized Controlled Trial

The study aimed to investigate the independent and combined effects of consuming a high-protein dairy milk beverage, twice daily, with or without a progressive resistance training (PRT) program on outcomes of age-related sarcopenia, in healthy active older (≥50 years) adults. In this 12-week, 2 × 2 factorial study, participants were randomly allocated into one of four groups: dairy milk beverage (DM), exercise and dairy milk beverage (EX+DM), exercise alone (EX), and control (CON). The EX group underwent a 12-week whole-body PRT schedule (three sessions/week) and a high-protein dairy milk beverage (DM) was consumed twice daily (30 g protein/day). At weeks 0, 6, and 12, body composition (iDXA), strength [one-repetition maximum (1RM): leg press, chest press, lateral (lat) pull-down, and handgrip], power (countermovement jump), cardiorespiratory fitness (VO2), and physical performance (gait speed) were measured. Before measurements, blood samples were collected to determine the immune (i.e., leukocyte trafficking and inflammatory cytokines) and hormonal (i.e., insulin, cortisol, IGF-1, testosterone, and estradiol) profiles. Participants (n = 37) completed the study within the controlled experimental conditions. Protein intake increased in the EX+DM [mean ± SD, 1.2 ± 0.2 to 1.8 ± 0.4 g/kg body mass (BM) per day-1] and DM (1.3 ± 0.5 to 1.8 ± 0.6 g kg-1 BM day-1) groups during the intervention. Absolute fat-free mass increased in the EX+DM [mean (95% confidence interval) = 0.65 (0.25-1.0) kg] and EX [0.49 (-0.44 to 1.40) kg] groups (P < 0.001) compared to DM [-0.54 (-1.6 to 0.05) kg]. Relative fat mass decreased (group*time, P = 0.018) in DM [-1.8% (-3.3 to -0.35%)] and EX+DM [-1.3% (-2.3 to -0.31%)], which was a greater reduction than that in the CON [0.10% (-0.80 to 1.0%)] group (P < 0.01). Relative maximal strength increased in both the EX and EX+DM (≥35%, P < 0.05) groups, but not in the DM and CON groups. The change in 1RM strength outcomes was higher in EX+DM compared to all other groups (53-78%, P < 0.01). There was an increase in resting plasma IL-10 concentration in EX+DM (88%), compared to all the other groups (P = 0.016). No other differences in systemic inflammatory cytokines were observed. There were no significant changes in all hormone concentrations measured among all groups. In conclusion, a high-protein dairy milk beverage providing additional protein did not further enhance the effects of PRT on outcomes of fat-free mass, power, or physical performance. However, there was a significant augmentative effect for high-protein dairy milk consumption on changes to maximal strength outcomes during PRT in healthy active older adults.

Impact of dietary protein intake on the incidence of low muscle strength in middle-aged and older adults

BACKGROUND

A reduction in skeletal muscle strength is a prognostic indicator of negative consequences, such as physical disability, frailty, and mortality in older adults. Studies investigating associations between the risk of reduction in skeletal muscle strength and the amount of dietary protein which is a factor influenced muscle health are scarce, particularly in Asian populations. Therefore, we investigated the association between the amount and change in daily protein intake and the prospective risk of developing low skeletal muscle strength in middle-aged and older adults.

METHODS

This study used data from the Korean Genome and Epidemiology Study as an ongoing population-based cohort study of adults aged 40 years and over. The amount of daily protein consumed was assessed using a semi-quantitative food frequency questionnaire. Low skeletal muscle strength was measured with a handgrip strength dynamometer.

RESULTS

In total, 32,458 adults (11,358 males and 21,100 females) were evaluated. The amount of daily dietary protein consumed was not associated with the risk of low muscle strength over the 4-year follow-up period after adjusting for covariates. No associations between low muscle strength events according to the change in the amount of protein consumed from the baseline to the follow-up surveys were identified.

CONCLUSIONS

The amount of and change in dietary protein consumed were not associated with developing low muscle strength in middle-aged and older adults. Further studies with a focus on physical activity-protein intake interactions and specific conditions, such as mobility-limited adults or hospitalized patients, are warranted to clarify the relationship between protein intake status and the incidence of low skeletal muscle strength.

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.

Protein Intake, Protein Mealtime Distribution and Seafood Consumption in Elderly Norwegians: Associations with Physical Function and Strength

Protein intake is considered important in the maintenance of muscle health in ageing. However, both the source and mealtime distribution of protein might affect the intake of protein and its effect on muscle protein synthesis. In this study, protein intake, mealtime distribution of protein, and seafood consumption were assessed in 92 older adults (aged 65+), and associations with physical performance (Short Physical Performance Battery (SPPB)), grip strength and gait speed were assessed in a multiple linear regression analysis. The participants had a mean age of 73 ± 8.9 years. Mean protein intake was 1.1 g/kg body weight. Protein intake was well distributed, with coefficient of variance between meals (CV meals) 0.6 ± 0.3. However, dinner had the highest protein intake. No associations were found between the nutrition factors and physical performance or strength; however, this result might have been caused by a ceiling effect in the chosen test batteries, as the mean score on SPPB was 10.3 ± 2.7, and 48.9% of the participants reached the top score of 12 points. Mean grip strength was 44.4 ± 9.4 kg (men) and 26.2 ± 6.8 kg (women). Mean gait speed was 1.0 ± 0.3 m/s. The interaction analysis suggests that there might be gender differences in the effect of seafood consumption on gait speed.

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.

A Review of Nutritional Requirements of Adults Aged ≥65 Years in the UK

Appropriate dietary choices in later life may reduce the risk of chronic diseases and rate of functional decline, however, there is little well-evidenced age-specific nutritional guidance in the UK for older adults, making it challenging to provide nutritional advice. Therefore, the aim of this critical review was to propose evidence-based nutritional recommendations for older adults (aged ≥65 y). Nutrients with important physiological functions in older adults were selected for inclusion in the recommendations. For these nutrients: 1) recommendations from the UK Scientific Advisory Committee for Nutrition (SACN) reports were reviewed and guidance retained if recent and age-specific, and 2) a literature search conducted where SACN guidance was not sufficient to set or confirm recommendations for older adults, searching Web of Science up to March 2020. Data extracted from a total of 190 selected publications provided evidence to support age-specific UK recommendations for protein (1.2 g·kg-1·d-1), calcium (1000 mg·d-1), folate (400 μg·d-1), vitamin B-12 (2.4 μg·d-1), and fluid (1.6 L·d-1 women, 2.0 L·d-1 men) for those ≥65 y. UK recommendations for carbohydrates, free sugars, dietary fiber, dietary fat and fatty acids, sodium, and alcohol for the general population are likely appropriate for older adults. Insufficient evidence was identified to confirm or change recommendations for all other selected nutrients. In general, significant gaps in current nutritional research among older adults existed, which should be addressed to support delivery of tailored nutritional guidance to this age group to promote healthy aging.

Dietary Protein Intake and Determinants in Māori and Non-Māori Octogenarians. Te Puāwaitanga o Ngā Tapuwae Kia Ora Tonu: Life and Living in Advanced Age: A Cohort Study in New Zealand

Protein intake, food sources and distribution are important in preventing age-related loss of muscle mass and strength. The prevalence and determinants of low protein intake, food sources and mealtime distribution were examined in 214 Māori and 360 non-Māori of advanced age using two 24 h multiple pass recalls. The contribution of food groups to protein intake was assessed. Low protein intake was defined as ≤0.75 g/kg for women and ≤0.86 g/kg for men. A logistic regression model was built to explore predictors of low protein intake. A third of both women (30.9%) and men (33.3%) had a low protein intake. The main food group sources were beef/veal, fish/seafood, milk, bread though they differed by gender and ethnicity. For women and men respectively protein intake (g/meal) was lowest at breakfast (10.1 and 13.0), followed by lunch (14.5 and 17.8) and dinner (23.3 and 34.2). Being a woman (p = 0.003) and having depressive symptoms (p = 0.029) were associated with consuming less protein. In adjusted models the odds of adequate protein intake were higher in participants with their own teeth or partial dentures (p = 0.036). Findings highlight the prevalence of low protein intake, uneven mealtime protein distribution and importance of dentition for adequate protein intake among adults in advanced age.

Safety of a Combined WB-EMS and High-Protein Diet Intervention in Sarcopenic Obese Elderly Men

Purpose

Whole-body electromyostimulation (WB-EMS) especially in combination with a high-protein supplementation has been established as an efficient treatment against sarcopenia. However, there are several case reports of rhabdomyolysis after WB-EMS application. Thus, we asked if this training could potentially lead to deteriorations of the cardiac as well as the renal function.

Materials and Methods

One hundred sarcopenic obese men aged 70 years and older were randomly balanced (1-1-1) and allocated to one of the three study arms. During 16 weeks of intervention, these groups either performed WB-EMS and took a protein supplement (WB-EMS&P), solely received the protein supplement (Protein) or served as control group (CG). WB-EMS consisted of 1.5×20 min (85 Hz, 350 μs, 4 s of strain to 4 s of rest) applied with moderate-to-high intensity while moving. We further generated a daily protein intake of 1.7-1.8 g/kg/body mass per day. At baseline and 8-10 days after completion of the intervention, blood was drawn and biomarkers of muscle, cardiac and renal health were assessed.

Results

Hereby, we found slight but significant elevations of creatine kinase (CK) levels in the WB-EMS group pointing to minor damages of the skeletal muscle (140 U/l [81-210], p < 0.001). This was accompanied by a significant, low-grade increase of creatine kinase-muscle brain (CK-MB, 0.43 ng/mL [-0.29-0.96], p < 0.01) and high-sensitivity troponin T (hsTnT, 0.001 ng/mL. [0.000-0.003], p < 0.001) but without a higher risk of developing heart failure according to N-terminal prohormone of brain natriuretic peptide (NT-proBNP, -5.7 pg/mL [-38.8-24.6], p = 0.17). Estimated glomerular filtration rate (eGFR) was impaired neither by the high-protein supplementation alone nor in combination with WB-EMS (CG 76.0 mL/min/1.73 m² [71.9-82.2] vs Protein 73.2 mL/min/1.73 m² [63.0-78.9] vs WB-EMS&P 74.6 mL/min/1.73 m² [62.8-84.1], p = 0.478).

Conclusion

In conclusion, even in the vulnerable group of sarcopenic obese seniors, the combination of WB-EMS with a high-protein intake revealed no short-term, negative impact on the eGFR, but potential consequences for the cardiovascular system need to be addressed in future studies.

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

There is a shift in thinking about dietary protein requirements from daily requirements to individual meal requirements. Per meal, stimulation of muscle protein synthesis has a saturable dose relationship with the quantity of dietary protein consumed. Protein intake above the saturable dose does not further contribute to the synthetic response; the "excess" amino acids are predominantly oxidized. Given that daily dietary protein intake is finite, finding protein distribution patterns that both reduce amino acid oxidation and maximize their contribution towards protein synthesis (in theory improving net balance) could be "optimal" and is of practical scientific interest to promote beneficial changes in skeletal muscle-related outcomes. This article reviews both observational and randomized controlled trial research on the protein distribution concept. The current evidence on the efficacy of consuming an "optimal" protein distribution to favorably influence skeletal muscle-related changes is limited and inconsistent. The effect of protein distribution cannot be sufficiently disentangled from the effect of protein quantity. Consuming a more balanced protein distribution may be a practical way for adults with marginal or inadequate protein intakes (<0.80 g·kg^-1·d^-1) to achieve a moderately higher total protein intake. However, for adults already consuming 0.8-1.3 g·kg^-1·d^-1, the preponderance of evidence supports that consuming at least one meal that contains sufficient protein quantity to maximally stimulate muscle protein synthesis, independent of daily distribution, is helpful to promote skeletal muscle health.

Distribution of daily protein intake across meals and lower extremity functioning in community-dwelling Spanish older adults: a prospective cohort study

PURPOSE

Total dietary protein intake has been associated with better physical function in older adults. However, it is unclear whether an even mealtime distribution of protein intake also has an impact on physical functioning. The aim of this study was to examine the prospective association between distribution of daily protein intake across meals and the risk of impaired lower extremity function (ILEF).

METHODS

We used information of 2975 individuals ≥ 60 years from the Seniors-ENRICA cohort. Habitual dietary protein intake was assessed in 2008-2010 with a validated diet history. For each participant, dietary protein intake across meals was determined using the coefficient of variation (CV) of the distribution. Study participants were followed up until 2017 to identify incident ILEF, assessed with the short physical performance battery (SPPB).

RESULTS

Over a median follow-up of 6.3 years, we identified 521 participants with ILEF (SPPB ≤ 6). After adjusting for potential confounders including total protein intake/kg/day, a higher CV (less even distribution) of protein intake did not show an association with the risk of ILEF [hazard ratios (HR) and 95% confidence intervals (CI) for second and third vs. the first tertile: 1.08 (0.87-1.34), and 1.06 (0.85-1.32), respectively; p trend = 0.60]. When assessing each component of the SPPB, a higher CV of protein intake was associated with higher risk of impaired standing balance (HR for tertile 3 vs. tertile 1: 1.26 (1.03-1.54); p trend = 0.02).

CONCLUSION

The mealtime distribution of protein intake was not associated with ILEF. The possibility of a detrimental effect of uneven distribution of protein on standing balance needs to be further investigated.

Protein intake in older people : Why, how much and how?

The protein intake of older people has gained increasing scientific interest as a potential factor to delay the age-associated decline in muscle mass and consequently to counteract the development of sarcopenia. The skeletal muscle of older people seems less responsive to the anabolic stimulus of protein intake. Therefore, higher protein needs are discussed to overcome this anabolic resistance and to maintain muscle mass as far as possible. Besides the total amount of protein consumed, the distribution, quality and timing in relation to physical exercise are considered relevant; however, deriving clear recommendations for clinical practice is still difficult as positive results of protein intake on muscle metabolism found in experimental trials cannot simply be transferred to everyday conditions and randomized controlled trials often failed to show improvements in muscular outcomes related to protein supplementation. The effectiveness of protein supplementation may depend on functional resources of the older persons and the habitual protein intake. There is still a need for studies with well-defined protocols and populations to further elucidate the role of protein in the prevention and treatment of sarcopenia.

The Relationship Between Healthy Eating Motivation and Protein Intake in Community-Dwelling Older Adults With Varying Functional Status

In older adults, the relationship between healthy eating motivation (HEM) and protein intake as key component of a healthy diet is poorly understood. Therefore, we investigate the association of HEM with (1) total protein intake and (2) intake of different protein sources in older adults with varying functional status. In this cross-sectional study including 250 adults (≥70 years), we assessed HEM with “The Eating Motivation Survey” and protein intake by 7-day food records. In addition, gender, age, Body Mass Index (BMI), energy intake and functional status were considered. Regression analyses revealed that HEM was neither related to total (β = −0.02; p = 0.723) nor to relative protein intake (β = 0.04; p = 0.370). Notwithstanding this, participants with stronger HEM showed lower intake of protein from meat and meat products (β = −0.14; p = 0.018), higher intake of overall plant-based protein (β = 0.11; p = 0.032), protein from fruit and vegetables (β = 0.20; p = 0.002) and from pulses, nuts an seeds (β = 0.16; p = 0.016). Our findings suggest HEM as a valuable indicator for intake of distinct protein sources. However, since HEM is not related to total protein intake, the importance of sufficient protein consumption should be emphasized by promoting healthy eating, regardless of self-perceived HEM.

Protein-Related Dietary Parameters and Frailty Status in Older Community-Dwellers across Different Frailty Instruments

The present study investigated the associations between frailty status and (a) daily protein intake, (b) daily body weight-adjusted protein intake, (c) branched-chain amino acid (BCAA) consumption, (d) evenness of protein distribution across main meals, (e) number of daily meals providing at least 30 g of protein, and (f) number of daily meals providing at least 0.4 g protein/kg of body weight in community-dwelling older adults. The relationship between frailty status and protein-related dietary parameters was explored across different frailty assessment tools. Two hundred older adults were enrolled in the study. Participant frailty status was determined according to a modified Fried’s frailty phenotype (mFP), the FRAIL scale, and the Study of Osteoporotic Fracture (SOF) index. Diet was assessed by 24-h dietary recall, while diet composition was estimated using a nutritional software. A frailty instrument-dependent relationship was observed between frailty status and protein-related dietary parameters. Protein consumption was associated with frailty status only in participants identified as frail according to the mFP. In addition, protein and BCAA intake was found to be greater in robust and pre-frail participants relative to their frail counterparts. Our findings suggest that the association between frailty and protein-related dietary parameters is tool dependent. Specifically, protein and BCAA consumption appears to be lower only in older adults identified as frail by the mFP.

The Consumption of Two or Three Meals per Day with Adequate Protein Content Is Associated with Lower Risk of Physical Disability in Mexican Adults Aged 60 Years and Older

Adequate protein intake per day has been associated with a lower risk of physical disability; however, if adequate protein intake per meal is also associated is unknown. The purpose of this study was to analyze the association between adequate protein intake per meal and physical disability in daily living activities in Mexican adults aged ≥60 years. We assessed the number of meals per day with an adequate protein content (24 h dietary recall), the presence of physical disability in daily living activities (two validated questionnaires), and their association in 187 participants through logistic regression. Consuming two or three meals per day with ≥30 g each was associated with lower risk of physical disability on Transportation (OR [95% CI]: 0.06 [0.01–0.50], p = 0.01), Shopping (0.05 [0.01–0.40], p = 0.004), Feeding (0.06 [0.01–0.74], p = 0.028), and Transfer (0.09 [0.01–0.98], p = 0.048). On the other hand, consuming two or three meals per day with ≥0.4 g/kg each was associated with lower risk of physical disability on Shopping (0.21 [0.05–0.89], p = 0.034) and Transportation (0.12 [0.03–0.48], p = 0.003). The consumption of two or three meals per day with adequate protein content is associated with lower risk of physical disability in Mexican adults aged 60 years and older.

Dietary Protein, Exercise, and Frailty Domains

Increasing awareness of the impact of frailty on elderly people resulted in research focusing on factors that contribute to the development and persistence of frailty including nutrition and physical activity. Most effort so far has been spent on understanding the association between protein intake and the physical domain of frailty. Far less is known for other domains of frailty: cognition, mood, social health and comorbidity. Therefore, in the present narrative review, we elaborate on the evidence currently known on the association between protein and exercise as well as the broader concept of frailty. Most, but not all, identified studies concluded that low protein intake is associated with a higher prevalence and incidence of physical frailty. Far less is known on the broader concept of frailty. The few studies that do look into this association find a clear beneficial effect of physical activity but no conclusions regarding protein intake can be made yet. Similar, for other important aspects of frailty including mood, cognition, and comorbidity, the number of studies are limited and results are inconclusive. Future studies need to focus on the relation between dietary protein and the broader concept of frailty and should also consider the protein source, amount and timing.

Daily and per-meal animal and plant protein intake in relation to muscle mass in healthy older adults without functional limitations: an enable study

OBJECTIVE

Animal protein sources are considered to be of higher quality than plant protein sources in terms of stimulating muscle metabolism. Our objective was to investigate whether protein intake from animal and plant sources on a daily and per-meal basis differs between healthy older adults with normal and with low muscle mass.

METHODS

In this cross-sectional study including 100 healthy, community-dwelling adults (51 women) aged 75-85 years without functional limitations dietary intake was assessed using 7-day food records. Protein intake was classified by six animal and six plant protein sources. Skeletal muscle index (SMI) was determined based on bioelectrical impedance analysis and categorized into 'normal' or 'low' (men ≤ 8.50, women ≤ 5.75 kg/m²). The absolute animal and plant protein intake and their proportion of total protein intake were compared between these groups using Mann-Whitney U test.

RESULTS

Daily protein intake was 0.96 ± 0.27 g/kg body weight (BW), 61 ± 10% hereof were from animal origin with no difference between men and women. SMI was low in 39% of men and 35% of women. No differences in absolute daily animal and plant protein intake between participants with normal vs. low SMI were observed. The proportion of animal protein was not different on neither a daily nor a per-meal basis between those with normal and those with low SMI. Women with low SMI consumed less animal protein (in g) for breakfast (4.8 ± 4.1 g vs. 8.5 ± 6.9 g, p = 0.031) and fewer meals per day with at least 50% animal protein (2.2 ± 0.9 vs. 2.7 ± 1.0, p = 0.046) compared to those with normal SMI.

CONCLUSION

On a daily basis, the absolute and relative animal protein intake does not differ between healthy older adults without functional limitations with normal vs. low SMI. However, our results indicate that in women animal protein intake on a per-meal basis might be of relevance for the maintenance of muscle mass.

Measuring eating motives in older adults with and without functional impairments with The Eating Motivation Survey (TEMS)

Gaining a better understanding which motives play a role in daily eating is crucial in order to develop personalized interventions promoting adequate diet. The Eating Motivation Survey (TEMS) is a comprehensive tool to assess manifold reasons for eating but has not been specifically applied in an older sample including very old persons and persons differing in functional status. Therefore, the first step of the study was to investigate whether the basic motives of TEMS are consistent in an older sample and comparable across older adults with and without functional impairments. Second, the study aimed at describing which motives underlie eating behavior in older age most often as well as to analyze the relationship between eating motives and functional status. 376 community-dwelling older persons aged 70 years and older filled in the brief survey version (15 motives à 3 items) of TEMS. The sample comprises 149 unimpaired and 227 impaired participants in terms of physical function. Confirmatory factor analysis yielded good model fit with RMSEA 0.036 and SRMR 0.048. Furthermore, multi-group analysis revealed a generally invariant factor structure across participants with and without functional impairments. Liking was rated to underlie eating behavior most often, followed by Health and Natural Concerns. Considering gender, age and BMI, significant associations between functional status and the motive Sociability emerged. Since the results suggest that the fifteen basic eating motives are generalizable in older age and across different functional states, TEMS might be a valuable tool in nutrition-related health promotion to developing individualized approaches considering health aspects as well as hedonistic factors.

Muscle adaptation in response to a high-intensity interval training in obese older adults: effect of daily protein intake distribution

BACKGROUND

Aging is associated with declines in muscle mass, strength and quality, leading to physical impairments. An even protein distribution in daily meals has recently been proposed along with adequate total protein intake as important modulators of muscle mass. In addition, due to its short duration, high-intensity interval training (HIIT) has been highlighted as a promising intervention to prevent physical deterioration. However, the interaction between daily protein intake distribution and HIIT intervention in elderlies remain unknown.

OBJECTIVE

To investigate muscle adaptation following HIIT in older adults according to daily protein intake distribution.

METHODS

Thirty sedentary obese subjects who completed a 12-week elliptical HIIT program were matched [criteria: age (± 2 years), sex, BMI (± 2 kg/m²)] and divided a posteriori into 2 groups according to the amount of protein ingested at each meal: < 20 g in at least one meal (P20-, n = 15, 66.8 ± 3.7 years) and ≥ 20 g in each meal (P20+, n = 15, 68.1 ± 4.1 years). Body composition, functional capacity, muscle strength, muscle power, physical activity level, and nutritional intakes were measured pre- and post-intervention. A two way repeated ANOVA was used to determine the effect of the intervention (HIIT) and protein distribution (P20- vs P20+, p < 0.05).

RESULTS

No difference was observed at baseline between groups. Following the HIIT intervention, we observed a significant decrease in waist and hip circumferences and improvements in functional capacities in both P20- and P20 + group (p < 0.05). However, no protein distribution effect was observed.

CONCLUSION

A 12-week HIIT program is achievable and efficient to improve functional capacities as well as body composition in obese older adults. However, consuming at least 20 g of proteins in every meal does not further enhance muscle performance in response to a 12-week HIIT intervention.

Amount Rather than Animal vs Plant Protein Intake Is Associated with Skeletal Muscle Mass in Community-Dwelling Middle-Aged and Older Chinese Adults: Results from the Guangzhou Nutrition and Health Study

BACKGROUND

Current literature does not indicate if the amount and animal vs plant protein are equally important in the prevention of muscle loss in middle-aged and older Chinese adults.

OBJECTIVE

The aim of the study was to examine the associations between amount or animal vs plant protein and skeletal muscle mass in Chinese adults aged 40 to 80 years.

DESIGN

A cross-sectional analysis of a prospective, community-based cohort was performed.

PARTICIPANTS/SETTING

Participants included 1,044 men and 2,169 women aged 40 to 80 years from the Guangzhou Nutrition and Health Study 2011-2013 with body composition measurements by dual-energy x-ray absorptiometry.

MAIN OUTCOME MEASURE

The skeletal muscle index (SMI) was defined as appendicular skeletal muscle mass divided by body weight. Participants in the lowest quartile of the sex-specific SMI were considered to have low muscle mass (LMM).

STATISTICAL ANALYSIS

Analyses of covariance were performed to estimate the SMI across quintiles of relative dietary intake of total, animal, and plant protein and the ratio of animal-to-plant protein. Logistic regression models were applied to assess the associations between quintiles of protein intake and LMM.

RESULTS

The SMI increased significantly across quintiles of relative dietary intake of total, animal, and plant protein (all P trends<0.001). Odds ratios (95% CIs) for LMM among participants in the highest (vs lowest) quintile were 0.3 (0.2, 0.4) for total protein, 0.3 (0.2, 0.5) for animal protein, and 0.4 (0.3, 0.7) for plant protein, respectively (all P trends<0.001). However, the ratio of animal-to-plant protein was not associated with either the SMI or the presence of LMM.

CONCLUSION

Higher dietary intakes of total, animal, and plant protein, regardless of the ratio of animal-to-plant protein, are associated with greater skeletal muscle mass in community-dwelling middle-aged and older Chinese adults with a mean protein intake above the current recommendation for protein of 0.8 g/kg per day.

Inadequate Protein Intake at Specific Meals Is Associated with Higher Risk of Impaired Functionality in Middle to Older Aged Mexican Adults

Purpose

To describe the proportions of inadequate protein intake (IPI) per day and per meal and their association with functionality in middle to older aged Mexican adults.

Materials and Methods

In a cross-sectional design, we evaluated the protein intake and functionality of instrumental activities of daily living (IADL) and activities of daily living (ADL) of 190 middle to older aged Mexican adults. IPI was considered as any protein intake: <1.2 g/kg/day, <30 g/meal, or <0.4 g/kg/meal. Functionality was organized into three groups: high, middle, and low scores. The first was set as the reference, and the other was considered as impaired functionality. With a multinomial logistic regression, we analyzed the association between IPI per day and per meal with impaired functionality.

Results

A high proportion of participants showed IPI per day. The meal with the highest proportion of IPI was dinner, followed by breakfast and lunch for both criteria. IPI at lunch was a significant risk factor for impaired functionality in ADL when assessed with the 30 g/meal criterion (low scores, OR 3.82 (95% CI, 1.15–12.65); middle scores, OR 2.40 [1.03–5.62]). For the 0.4 g/kg/meal criterion, IPI at dinner was a significant risk factor for IADL middle scores only (OR 7.64, [1.27–45.85]).

Conclusion

IPI per meal is high in middle to older aged Mexican adults, and at specific meals, it is a significant risk factor for impaired functionality in activities of daily living.

Mitochondria as a Target for Mitigating Sarcopenia

Sarcopenia is the loss of muscle mass, strength, and physical function that is characteristic of aging. The progression of sarcopenia is gradual but may be accelerated by periods of muscle loss during physical inactivity secondary to illness or injury. The loss of mobility and independence and increased comorbidities associated with sarcopenia represent a major healthcare challenge for older adults. Mitochondrial dysfunction and impaired proteostatic mechanisms are important contributors to the complex etiology of sarcopenia. As such, interventions that target improving mitochondrial function and proteostatic maintenance could mitigate or treat sarcopenia. Exercise is currently the only effective option to treat sarcopenia and does so, in part, by improving mitochondrial energetics and protein turnover. Exercise interventions also serve as a discovery tool to identify molecular targets for development of alternative therapies to treat sarcopenia. In summary, we review the evidence linking mitochondria and proteostatic maintenance to sarcopenia and discuss the therapeutic potential of interventions addressing these two factors to mitigate sarcopenia.

Do Aspects of Protein Intake Vary Across the Week in Healthy Community-Dwelling Older Adults?-An enable Study

Various aspects of protein intake are thought to be crucial for the prevention of sarcopenia in older adults. Information about the day-to-day variation in these aspects is lacking. Our objective was to examine whether daily protein intake, protein distribution across meals, number of meals providing adequate protein, and protein sources vary across the week in healthy community-dwelling older adults. In 140 persons (51% women) that were aged 75–85 years, protein intake was assessed by seven-day food records. On average across the week, protein intake (median [IQR]) was 0.93 [0.79–1.10] g/kg body weight (BW) and the coefficient of variation across the three main meals was 0.50 [0.40–0.61]. The number of meals per day providing ≥0.4 g protein/kg BW was 0.57 [0.43–1.00] and 60.0 [52.4–65.2]% of protein intake was animal-based. According to Friedman’s test, differences throughout the week were observed in women for daily protein intake (p = 0.038; Sunday: 0.99 [0.78–1.31] vs. Tuesday: 0.79 [0.68–1.12] g/kg BW) and number of meals with adequate protein (p = 0.019; ≥1 daily meal: Sunday: 69.4% vs. Tuesday: 41.7%). On Sunday, protein intake was most in agreement with suggestions to prevent sarcopenia. In men, protein intake did not differ throughout the week.

An Update on Protein, Leucine, Omega-3 Fatty Acids, and Vitamin D in the Prevention and Treatment of Sarcopenia and Functional Decline

Aging is associated with sarcopenia and functional decline, leading to frailty and disability. As a modifiable risk factor, nutrition may represent a target for preventing or postponing the onset of these geriatric conditions. Among nutrients, high-quality protein, leucine, vitamin D, and omega-3 polyunsaturated fatty acids (n-3 PUFA) are of particular interest for their demonstrated effects on skeletal muscle health. This narrative review aims to examine the recent observational and interventional evidence on the associations and the role of these nutrients in the muscle mass, strength, mobility, and physical function of free-living older adults, who are either healthy or at risk of frailty. Recent evidence supports a higher protein intake recommendation of 1.0⁻1.2 g/kg/day in healthy older adults; an evenly distributed mealtime protein intake or minimal protein per meal may be beneficial. In addition, vitamin D supplementation of 800⁻1000 IU, particularly when vitamin D status is low, and doses of ~3 g/day of n-3 PUFA may be favorable for physical function, muscle mass, and strength. Reviewed studies are highly heterogenous, yet the quantity, quality, and timing of intakes should be considered when designing intervention studies. Combined protein, leucine, vitamin D, and n-3 PUFA supplements may convey added benefits and may represent an intervention strategy in the prevention of sarcopenia and functional decline.

[The Influence of Protein on the Prevention of Fragility Fractures Among Senior Adults]

The Influence of Protein on the Prevention of Fragility Fractures Among Senior Adults Abstract. The aim of this review article is to discuss protein intake in senior adults at risk for fragility fractures as a modifiable factor for fracture prevention. Proteins are building blocks of the bone matrix and the muscles. This dual function fits in with the concept of prevention of fragility fractures in senior adults aimed at reducing both bone loss and falls. In older adults, a protein-rich diet could be another simple and effective way to promote bone and muscle health, in addition to the established recommendations for adequate vitamin D and calcium intake.