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Special Issue "Dietary Protein and Muscle in Aging People"

A special issue of Nutrients (ISSN 2072-6643).

Deadline for manuscript submissions: closed (15 June 2018)

Special Issue Editors

Guest Editor
Dr. Matteo Cesari

1. Fondazione IRCCS Ca’ Granda – Ospedale Maggiore Policlinico, Milan, Italy
2. Geriatric Unit, Department of Medical Sciences and Community Health, University of Milan, Milan, Italy
Website | E-Mail
Interests: geriatrics; frailty; sarcopenia; healthy aging
Guest Editor
Dr. Emanuele Marzetti

Policlinico Universitario Agostino Gemelli; Department of Geriatrics, Neurosciences and Orthopaedics; Rome, Italy
Website | E-Mail
Interests: Geriatrics; Frailty; Sarcopenia; Mitochondria; Biomarkers

Special Issue Information

Dear Colleagues,

This Special Issue of Nutrients, entitled “Dietary Proteins and Muscle in Aging People”, welcomes the submission of manuscripts either reporting original research or reviewing the scientific literature. Manuscripts should focus on the mechanisms linking dietary protein with muscle quality and quantity. Articles presenting (both positive and negative) results from clinical trials testing protein interventions on muscle mass and function are welcome. The Special Issue aims at including articles spanning different disciplines (e.g., nutritional sciences, geriatrics, sports medicine, public health, rheumatology, oncology, cardiology, orthopedics) for exploring the topic of interest. Reports from basic up to clinical and population research are suitable. Articles adopting a longitudinal approach or reporting data from life-long interventions/observations in the exploration of the theme will be given special consideration.

Potential topics include, but are not limited to:

  • Description of patterns of dietary protein consumption across life
  • Influence of dietary protein intake on the functional status of older people
  • Preclinical and clinical studies describing the mechanisms through which protein intake modifies muscle mass and function
  • Protein/amino acid supplementation interventions against sarcopenia, cachexia or disease conditions associated with muscle wasting in old age
  • Disease-specific alterations modifying the effects of dietary protein intake on the skeletal muscle
  • Interactions of dietary protein intake and gut microbiota on skeletal muscle
Dr. Matteo Cesari
Dr. Emanuele Marzetti
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nutrients is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Proteins
  • Diet
  • Sarcopenia
  • Skeletal muscle
  • Cachexia
  • Supplementation

Published Papers (10 papers)

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Research

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Open AccessArticle A Distinct Pattern of Circulating Amino Acids Characterizes Older Persons with Physical Frailty and Sarcopenia: Results from the BIOSPHERE Study
Nutrients 2018, 10(11), 1691; https://doi.org/10.3390/nu10111691
Received: 17 September 2018 / Revised: 30 October 2018 / Accepted: 1 November 2018 / Published: 6 November 2018
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Abstract
Physical frailty and sarcopenia (PF&S) are hallmarks of aging that share a common pathogenic background. Perturbations in protein/amino acid metabolism may play a role in the development of PF&S. In this initial report, 68 community-dwellers aged 70 years and older, 38 with PF&S
[...] Read more.
Physical frailty and sarcopenia (PF&S) are hallmarks of aging that share a common pathogenic background. Perturbations in protein/amino acid metabolism may play a role in the development of PF&S. In this initial report, 68 community-dwellers aged 70 years and older, 38 with PF&S and 30 non-sarcopenic, non-frail controls (nonPF&S), were enrolled as part as the “BIOmarkers associated with Sarcopenia and Physical frailty in EldeRly pErsons” (BIOSPHERE) study. A panel of 37 serum amino acids and derivatives was assayed by UPLC-MS. Partial Least Squares–Discriminant Analysis (PLS-DA) was used to characterize the amino acid profile of PF&S. The optimal complexity of the PLS-DA model was found to be three latent variables. The proportion of correct classification was 76.6 ± 3.9% (75.1 ± 4.6% for enrollees with PF&S; 78.5 ± 6.0% for nonPF&S). Older adults with PF&S were characterized by higher levels of asparagine, aspartic acid, citrulline, ethanolamine, glutamic acid, sarcosine, and taurine. The profile of nonPF&S participants was defined by higher concentrations of α-aminobutyric acid and methionine. Distinct profiles of circulating amino acids and derivatives characterize older people with PF&S. The dissection of these patterns may provide novel insights into the role played by protein/amino acid perturbations in the disabling cascade and possible new targets for interventions. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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Open AccessArticle Impact of Meeting Different Guidelines for Protein Intake on Muscle Mass and Physical Function in Physically Active Older Women
Nutrients 2018, 10(9), 1156; https://doi.org/10.3390/nu10091156
Received: 2 July 2018 / Revised: 21 August 2018 / Accepted: 21 August 2018 / Published: 24 August 2018
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Abstract
The role of dietary protein intake on muscle mass and physical function in older adults is important for the prevention of age-related physical limitations. The aim of the present study was to elucidate links between dietary protein intake and muscle mass and physical
[...] Read more.
The role of dietary protein intake on muscle mass and physical function in older adults is important for the prevention of age-related physical limitations. The aim of the present study was to elucidate links between dietary protein intake and muscle mass and physical function in older women meeting current guidelines of objectively assessed physical activity. In 106 women (65 to 70 years old), protein intake was assessed using a 6-day food record and participants were classified into high and low protein intake groups using two Recommended Dietary Allowance (RDA) thresholds (0.8 g·kg−1 bodyweight (BW) and 1.1 g·kg−1 BW). Body composition, aerobic fitness, and quadriceps strength were determined using standardized procedures, and self-reported physical function was assessed using the SF-12 Health Survey. Physical activity was assessed by accelerometry and self-report. Women below the 0.8 g·kg−1 BW threshold had a lower muscle mass (p < 0.05) with no differences in physical function variables. When based on the higher RDA threshold (1.1 g·kg−1 BW), in addition to significant differences in muscle mass, women below the higher threshold had a significantly (p < 0.05) higher likelihood of having physical limitations. In conclusion, the present study supports the RDA threshold of 0.8 g·kg−1 BW of proteins to prevent the loss of muscle mass and emphasizes the importance of the higher RDA threshold of at least 1.1 g·kg−1 BW to infer additional benefits on constructs of physical function. Our study also supports the role of protein intake for healthy ageing, even in older adults meeting guidelines for physical activity. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
Open AccessArticle Sensory-Driven Development of Protein-Enriched Rye Bread and Cream Cheese for the Nutritional Demands of Older Adults
Nutrients 2018, 10(8), 1006; https://doi.org/10.3390/nu10081006
Received: 8 July 2018 / Revised: 26 July 2018 / Accepted: 30 July 2018 / Published: 1 August 2018
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Abstract
To promote healthy aging and minimize age-related loss of muscle mass and strength, adequate protein intake throughout the day is needed. Developing and commercializing protein-enriched foods holds great potential to help fulfill the nutritional demands of older consumers. However, innovation of appealing protein-enriched
[...] Read more.
To promote healthy aging and minimize age-related loss of muscle mass and strength, adequate protein intake throughout the day is needed. Developing and commercializing protein-enriched foods holds great potential to help fulfill the nutritional demands of older consumers. However, innovation of appealing protein-enriched products is a challenging task since protein-enrichment often leads to reduced food palatability. In this study, rye bread and cream cheese prototypes fortified by whey protein hydrolysate (WPH), whey protein isolate (WPI), and/or soy protein isolate (SPI) were developed. Both sensory properties and consumer liking of prototypes were evaluated. Results showed that different proteins had various effects on the sensory characters of rye bread and cream cheese. The taste and texture modification strategies had positive effects in counteracting negative sensory changes caused by protein-enrichment. Consumers preferred 7% WPH and 4% WPH + 4% SPI-enriched breads with taste and texture modified. Sour taste and dry texture had considerable effects on consumer liking of rye bread. Addition of WPI and butter enhanced the flavor of cream cheese and increased consumer acceptance. Protein-enrichment doubled the protein content in the most liked prototypes, which have the potential to be incorporated into older consumers’ diets and improve their protein intake substantially. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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Review

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Open AccessReview Low Protein Intake Is Associated with Frailty in Older Adults: A Systematic Review and Meta-Analysis of Observational Studies
Nutrients 2018, 10(9), 1334; https://doi.org/10.3390/nu10091334
Received: 23 July 2018 / Revised: 12 September 2018 / Accepted: 14 September 2018 / Published: 19 September 2018
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Abstract
(1) Background: Several factors have been suggested to be associated with the physiopathology of frailty in older adults, and nutrition (especially protein intake) has been attributed fundamental importance in this context. The objective of this study was to conduct a systematic review and
[...] Read more.
(1) Background: Several factors have been suggested to be associated with the physiopathology of frailty in older adults, and nutrition (especially protein intake) has been attributed fundamental importance in this context. The objective of this study was to conduct a systematic review and meta-analysis to investigate the relationship between protein intake and frailty status in older adults. (2) Methods: A search of scientific studies was conducted in the main databases (Medline, Scopus, Cochrane library), and in the reference lists of selected articles. The search terms included synonyms and Medical Subject Headings and involved the use of Boolean operators which allowed the combination of words and search terms. Observational studies—cross-sectional and longitudinal—that met the eligibility criteria were included in the review. Article selection and data extraction were performed by two independent reviewers. Meta-analyses with random effects were performed. Publication bias was measured using the Strengthening the Reporting of Observational Studies in Epidemiology instrument. (3) Results: In the final sample, 10 articles, seven cross-sectional and three longitudinal, were included in the present study. Overall, studies investigated a total of 50,284 older adults from three different continents between 2006 and 2018. Four cross-sectional studies were included in the meta-analyses. The results demonstrated that a high protein intake was negatively associated with frailty status in older adults (odds ratio: 0.67, confidence interval = 0.56 to 0.82, p = 0.0001). (4) Conclusions: Our findings suggest that a high consumption of dietary protein is inversely associated with frailty in older adults. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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Open AccessReview Relative Protein Intake and Physical Function in Older Adults: A Systematic Review and Meta-Analysis of Observational Studies
Nutrients 2018, 10(9), 1330; https://doi.org/10.3390/nu10091330
Received: 22 July 2018 / Revised: 3 September 2018 / Accepted: 13 September 2018 / Published: 19 September 2018
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Abstract
(1) Background: The present work aims to conduct a systematic review and meta-analysis of observational studies, in order to investigate the association of relative protein intake and physical function in older adults; (2) Methods: Observational studies, that investigated the association between protein intake
[...] Read more.
(1) Background: The present work aims to conduct a systematic review and meta-analysis of observational studies, in order to investigate the association of relative protein intake and physical function in older adults; (2) Methods: Observational studies, that investigated the association between protein intake and physical function in older adults, were retrieved from MEDLINE, SCOPUS, CINAHL, AgeLine, EMBASE, and Cochrane-CENTRAL. Two independent researchers conducted study selection and data extraction; (3) Results: Very high protein intake (≥1.2 g/kg/day) and high protein intake (≥1.0 g/kg/day) groups showed better lower limb physical functioning and walking speed (WS) performance, respectively, in comparison to individuals who present relative low protein (<0.80 g/kg/day) intake. On the other hand, relative high protein intake does not seem to propitiate a better performance on isometric handgrip (IHG) and chair rise in comparison to relative low protein intake. In addition, there were no significant differences in the physical functioning of high and middle protein intake groups; (4) Conclusions: In conclusion, findings of the present study indicate that a very high (≥1.2 g/kg/day) and high protein intake (≥1.0 g/kg/day) are associated with better lower-limb physical performance, when compared to low protein (<0.80 g/kg/day) intake, in community-dwelling older adults. These findings act as additional evidence regarding the potential need to increase protein guidelines to above the current recommendations. However, large randomized clinical trials are needed to confirm the addictive effects of high-protein diets (≥1.0 g/kg/day) in comparison to the current recommendations on physical functioning. All data are available in the Open ScienceFramework. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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Open AccessReview Muscle and Bone Health in Postmenopausal Women: Role of Protein and Vitamin D Supplementation Combined with Exercise Training
Nutrients 2018, 10(8), 1103; https://doi.org/10.3390/nu10081103
Received: 17 July 2018 / Revised: 11 August 2018 / Accepted: 13 August 2018 / Published: 16 August 2018
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Abstract
Menopause is an age-dependent physiological condition associated with a natural decline in oestrogen levels, which causes a progressive decrease of muscle mass and strength and bone density. Sarcopenia and osteoporosis often coexist in elderly people, with a prevalence of the latter in elderly
[...] Read more.
Menopause is an age-dependent physiological condition associated with a natural decline in oestrogen levels, which causes a progressive decrease of muscle mass and strength and bone density. Sarcopenia and osteoporosis often coexist in elderly people, with a prevalence of the latter in elderly women. The profound interaction between muscle and bone induces a negative resonance between the two tissues affected by these disorders worsening the quality of life in the postmenopausal period. It has been estimated that at least 1 in 3 women over age 50 will experience osteoporotic fractures, often requiring hospitalisation and long-term care, causing a large financial burden to health insurance systems. Hormonal replacement therapy is effective in osteoporosis prevention, but concerns have been raised with regard to its safety. On the whole, the increase in life expectancy for postmenopausal women along with the need to improve their quality of life makes it necessary to develop specific and safe therapeutic strategies, alternative to hormonal replacement therapy, targeting both sarcopenia and osteoporosis progression. This review will examine the rationale and the effects of dietary protein, vitamin D and calcium supplementation combined with a specifically-designed exercise training prescription as a strategy to counteract these postmenopausal-associated disorders. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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Open AccessReview Dietary Protein, Muscle and Physical Function in the Very Old
Nutrients 2018, 10(7), 935; https://doi.org/10.3390/nu10070935
Received: 2 July 2018 / Revised: 17 July 2018 / Accepted: 18 July 2018 / Published: 20 July 2018
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Abstract
There is an ongoing debate as to the optimal protein intake in older adults. An increasing body of experimental studies on skeletal muscle protein metabolism as well as epidemiological data suggest that protein requirements with ageing might be greater than many current dietary
[...] Read more.
There is an ongoing debate as to the optimal protein intake in older adults. An increasing body of experimental studies on skeletal muscle protein metabolism as well as epidemiological data suggest that protein requirements with ageing might be greater than many current dietary recommendations. Importantly, none of the intervention studies in this context specifically investigated very old individuals. Data on the fastest growing age group of the oldest old (aged 85 years and older) is very limited. In this review, we examine the current evidence on protein intake for preserving muscle mass, strength and function in older individuals, with emphasis on data in the very old. Available observational data suggest beneficial effects of a higher protein intake with physical function in the oldest old. Whilst, studies estimating protein requirements in old and very old individuals based on whole-body measurements, show no differences between these sub-populations of elderly. However, small sample sizes preclude drawing firm conclusions. Experimental studies that compared muscle protein synthetic (MPS) responses to protein ingestion in young and old adults suggest that a higher relative protein intake is required to maximally stimulate skeletal muscle MPS in the aged. Although, data on MPS responses to protein ingestion in the oldest old are currently lacking. Collectively, the data reviewed for this article support the concept that there is a close interaction of physical activity, diet, function and ageing. An attractive hypothesis is that regular physical activity may preserve and even enhance the responsiveness of ageing skeletal muscle to protein intake, until very advanced age. More research involving study participants particularly aged ≥85 years is warranted to better investigate and determine protein requirements in this specific growing population group. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
Open AccessReview Dietary Protein and Muscle in Aging People: The Potential Role of the Gut Microbiome
Nutrients 2018, 10(7), 929; https://doi.org/10.3390/nu10070929
Received: 8 June 2018 / Revised: 13 July 2018 / Accepted: 18 July 2018 / Published: 20 July 2018
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Abstract
Muscle mass, strength, and physical function are known to decline with age. This is associated with the development of geriatric syndromes including sarcopenia and frailty. Dietary protein is essential for skeletal muscle function. Resistance exercise appears to be the most beneficial form of
[...] Read more.
Muscle mass, strength, and physical function are known to decline with age. This is associated with the development of geriatric syndromes including sarcopenia and frailty. Dietary protein is essential for skeletal muscle function. Resistance exercise appears to be the most beneficial form of physical activity for preserving skeletal muscle and a synergistic effect has been noted when this is combined with dietary protein. However, older adults have shown evidence of anabolic resistance, where greater amounts of protein are required to stimulate muscle protein synthesis, and response is variable. Thus, the recommended daily amount of protein is greater for older people. The aetiologies and mechanisms responsible for anabolic resistance are not fully understood. The gut microbiota is implicated in many of the postulated mechanisms for anabolic resistance, either directly or indirectly. The gut microbiota change with age, and are influenced by dietary protein. Research also implies a role for the gut microbiome in skeletal muscle function. This leads to the hypothesis that the gut microbiome might modulate individual response to protein in the diet. We summarise the existing evidence for the role of the gut microbiota in anabolic resistance and skeletal muscle in aging people, and introduce the metabolome as a tool to probe this relationship in the future. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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Open AccessReview Resistance Training Prevents Muscle Loss Induced by Caloric Restriction in Obese Elderly Individuals: A Systematic Review and Meta-Analysis
Nutrients 2018, 10(4), 423; https://doi.org/10.3390/nu10040423
Received: 22 December 2017 / Revised: 2 February 2018 / Accepted: 14 February 2018 / Published: 29 March 2018
Cited by 1 | PDF Full-text (3550 KB) | HTML Full-text | XML Full-text
Abstract
It remains unclear as to what extent resistance training (RT) can attenuate muscle loss during caloric restriction (CR) interventions in humans. The objective here is to address if RT could attenuate muscle loss induced by CR in obese elderly individuals, through summarized effects
[...] Read more.
It remains unclear as to what extent resistance training (RT) can attenuate muscle loss during caloric restriction (CR) interventions in humans. The objective here is to address if RT could attenuate muscle loss induced by CR in obese elderly individuals, through summarized effects of previous studies. Databases MEDLINE, Embase and Web of Science were used to perform a systematic search between July and August 2017. Were included in the review randomized clinical trials (RCT) comparing the effects of CR with (CRRT) or without RT on lean body mass (LBM), fat body mass (FBM), and total body mass (BM), measured by dual-energy X-ray absorptiometry, on obese elderly individuals. The six RCTs included in the review applied RT three times per week, for 12 to 24 weeks, and most CR interventions followed diets of 55% carbohydrate, 15% protein, and 30% fat. RT reduced 93.5% of CR-induced LBM loss (0.819 kg [0.364 to 1.273]), with similar reduction in FBM and BM, compared with CR. Furthermore, to address muscle quality, the change in strength/LBM ratio tended to be different (p = 0.07) following CRRT (20.9 ± 23.1%) and CR interventions (−7.5 ± 9.9%). Our conclusion is that CRRT is able to prevent almost 100% of CR-induced muscle loss, while resulting in FBM and BM reductions that do not significantly differ from CR. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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Open AccessReview Protein-Amino Acid Metabolism Disarrangements: The Hidden Enemy of Chronic Age-Related Conditions
Nutrients 2018, 10(4), 391; https://doi.org/10.3390/nu10040391
Received: 15 February 2018 / Revised: 15 March 2018 / Accepted: 21 March 2018 / Published: 22 March 2018
Cited by 2 | PDF Full-text (3169 KB) | HTML Full-text | XML Full-text
Abstract
Proteins are macro-molecules crucial for cell life, which are made up of amino acids (AAs). In healthy people, protein synthesis and degradation are well balanced. However, in the presence of hypercatabolic stimulation (i.e., inflammation), protein breakdown increases as the resulting AAs are consumed
[...] Read more.
Proteins are macro-molecules crucial for cell life, which are made up of amino acids (AAs). In healthy people, protein synthesis and degradation are well balanced. However, in the presence of hypercatabolic stimulation (i.e., inflammation), protein breakdown increases as the resulting AAs are consumed for metabolic proposes. Indeed, AAs are biochemical totipotent molecules which, when deaminated, can be transformed into energy, lipids, carbohydrates, and/or biochemical intermediates of fundamental cycles, such as the Krebs’ cycle. The biochemical consequence of hyper-catabolism is protein disarrangement, clinically evident with signs such as sarcopenia, hypalbuminemia, anaemia, infection, and altered fluid compartmentation, etc. Hypercatabolic protein disarrangement (HPD) is often underestimated by clinicians, despite correlating with increased mortality, hospitalization, and morbidity quite independent of the primary disease. Simple, cheap, repeatable measurements can be used to identify HPD. Therefore, identification and treatment of proteins’ metabolic impairment with appropriate measurements and therapy is a clinical strategy that could improve the prognosis of patients with acute/chronic hypercatabolic inflammatory disease. Here, we describe the metabolism of protein and AAs in hypercatabolic syndrome, illustrating the clinical impact of protein disarrangement. We also illustrate simple, cheap, repeatable, and worldwide available measurements to identify these conditions. Finally, we provide scientific evidence for HPD nutritional treatment. Full article
(This article belongs to the Special Issue Dietary Protein and Muscle in Aging People)
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