title: Inflammaging and Skeletal Muscle: Can Protein Intake Make a Difference?
abstract: Inflammaging is the chronic low-grade inflammatory state present in the elderly, characterized by increased systemic concentrations of proinflammatory cytokines. It has been shown that inflammaging increases the risk of pathologic conditions and age-related diseases, and that it also has been associated with increased skeletal muscle wasting, strength loss, and functional impairments. Experimental evidence suggests that the increased concentrations of proinflammatory cytokines and primary tumor necrosis factor α observed in chronic inflammation lead to protein degradation through proteasome activation and reduced skeletal muscle protein synthesis (MPS) via protein kinase B/Akt downregulation. Dairy and soy proteins contain all the essential amino acids, demonstrate sufficient absorption kinetics, and include other bioactive peptides that may offer nutritional benefits, in addition to those of stimulating MPS. Whey protein has antioxidative effects, primarily because of its ability to enhance the availability of reduced glutathione and the activity of the endogenous antioxidative enzyme system. Soy protein and isoflavone-enriched soy protein, meanwhile, may counteract chronic inflammation through regulation of the nuclear transcription factor κB signaling pathway and cytokine production. Although evidence suggests that whey protein, soy protein, and isoflavone-enriched soy proteins may be promising nutritional interventions against the oxidative stress and chronic inflammation present in pathologic conditions and aging (inflammaging), there is a lack of information about the anabolic potential of dietary protein intake and protein supplementation in elderly people with increased systemic inflammation. The antioxidative and anti-inflammatory effects, as well as the anabolic potential of protein supplementation, should be further investigated in the future with well-designed clinical trials focusing on inflammaging and its associated skeletal muscle loss.
authors: School of Physical Education and Sports Science, University of Thessaly, Trikala, Greece.
authors: Dimitrios
authors: D
authors: Draganidis
authors: School of Physical Education and Sports Science, University of Thessaly, Trikala, Greece; Department of Nutrition and Health Research, Nestle Research Centre, Lausanne, Switzerland.
authors: Leonidas G
authors: LG
authors: Karagounis
authors: School of Physical Education and Sports Science, Democritus University of Thrace, Komotini, Greece.
authors: Ioannis
authors: I
authors: Athanailidis
authors: School of Physical Education and Sports Science, Democritus University of Thrace, Komotini, Greece.
authors: Athanasios
authors: A
authors: Chatzinikolaou
authors: School of Physical Education and Sports Science, University of Thessaly, Trikala, Greece; Institute of Human Performance and Rehabilitation, Centre for Research and Technology-Thessaly, Trikala, Greece; and.
authors: Athanasios Z
authors: AZ
authors: Jamurtas
authors: School of Physical Education and Sports Science, University of Thessaly, Trikala, Greece; ifatouros@pe.uth.gr.
authors: Ioannis G
authors: http://orcid.org/0000-0002-8475-8411
authors: IG
authors: Fatouros
mesh_terms: D000368:Aged; D000375:Aging / Q000187:drug effects*; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D002908:Chronic Disease; D004044:Dietary Proteins / Q000494:pharmacology*; D019587:Dietary Supplements; D015536:Down-Regulation; D005978:Glutathione / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000150:complications / Q000188:drug therapy*; D007529:Isoflavones / Q000494:pharmacology; D008894:Milk Proteins / Q000494:pharmacology; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism*; D009133:Muscular Atrophy / Q000150:complications / Q000188:drug therapy; D016328:NF-kappa B / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D011494:Protein Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D030262:Soybean Proteins / Q000494:pharmacology
chemical_list: D000893:Anti-Inflammatory Agents; D000975:Antioxidants; D004044:Dietary Proteins; D007529:Isoflavones; D008894:Milk Proteins; D009124:Muscle Proteins; D016328:NF-kappa B; D030262:Soybean Proteins; D011494:Protein Kinases; D051057:Proto-Oncogene Proteins c-akt; D005978:Glutathione
keywords: frailty; inflammaging; oxidative stress; skeletal muscle loss; soy protein; whey protein