Protein Intake and Frailty: A Matter of Quantity, Quality, and Timing

Abstract

Frailty is a geriatric syndrome that refers to a state of reduced resiliency to stressful events that occurs in response to physiological and/or psychosocial detriments. Frailty is a predictor of poor prognosis, given that frail older adults are at higher risk of many adverse health-related events. Hence, the identification of potential strategies to prevent the development and progression of frailty is of extreme importance for avoiding its negative outcomes. An adequate protein consumption is advocated as a possible intervention for the management of frailty in older adults due to its effects on muscle mass and physical function. However, empirical evidence is still needed to support this proposition. On the other hand, substantial evidence from observational studies has provided important information on the association between frailty and dietary protein-related parameters. Here, we provide a narrative review of the current literature regarding the association between protein intake (amount (how much?), quality (what type?), and distribution across meals (when?)) and frailty-related parameters. The ultimate aim of this work is to offer practical, evidence-based indications to healthcare professionals responsible for the care of frail older adults.

Fighting Sarcopenia in Ageing European Adults: The Importance of the Amount and Source of Dietary Proteins

“…It has previously been shown that plant-derived proteins may represent an inadequate source of the essential amino acids lysine and leucine [47][48][49], with a reduced capability to stimulate muscle protein synthesis [50][51][52][53][54][55], thereby promoting animal-derived proteins as the primary source for maintenance of muscle mass and function in older adults. However, several studies examining effects of plant-derived proteins on protein synthesis were based on isolated and generally low digestible plant sources, such as soya and wheat [24,25,51,52,56]. Interestingly, it has been suggested that no deficits regarding essential amino acids such as lysine would be expected to occur with relative intakes of plant-derived proteins below 70% of total intake [57].…”

Protein Intake and Cognitive Function in Older Adults: A Systematic Review and Meta-Analysis

“…This nutritional aspect deserves concern, given that animal protein is expected to provide higher amounts of BCAA than vegetal protein. 42 - 44 BCAAs are directly and indirectly involved in numerous metabolic processes in the neural system. 45 - 49 However, much attention has been paid to their effects on GLU metabolism, given that it might serve as a possible mechanistic explanation for the association between protein intake and cognitive function.…”

Aging, Gut Microbiota and Metabolic Diseases: Management through Physical Exercise and Nutritional Interventions

“…Negative results of a dietary intervention in an elderly population in terms of gut microbiota composition modification were reported by Mitchell et al [ 84 ]. Based on the recommendations of increasing protein intake in the elderly [ 95 ], 30 individuals aged 70 or older were allocated either to a group consuming the recommended dietary allowance (RDA) of protein or to a group consuming twice the RDA for 10 weeks. No differences in the microbiota composition or in the faecal volatile organic compounds were detected as a consequence of the intervention.…”