Dietary Protein, Muscle and Physical Function in the Very Old

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 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.

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

“…Surprisingly, in a study also from the UK, including community-dwelling persons aged ≥85 years, revealed a slightly lower prevalence (28%) than our comparatively younger sample [12], which may be due to the targeted inclusion of people with moderate to severe functional impairments in our study. In summary, our results support the need for more targeted public health campaigns addressing sufficient protein intake as part of a health-promoting diet since the respective reference values are often not reached [8,[39][40][41].…”

Nutritional Status as a Mediator of Fatigue and Its Underlying Mechanisms in Older People

“…In addition to protein amount, protein source is also important. Plant-based proteins are considered to have a less anabolic effects (partly due to their low content in essential amino acids and leucine) than animal proteins [113,115]. However, it has been suggested that an adequate protein intake can also be achieved by combining plant-based and animal protein sources [115].…”

“…Plant-based proteins are considered to have a less anabolic effects (partly due to their low content in essential amino acids and leucine) than animal proteins [113,115]. However, it has been suggested that an adequate protein intake can also be achieved by combining plant-based and animal protein sources [115]. Additionally, fast digested proteins seem to better stimulate muscle protein accretion, even if results should be confirmed in larger trials [113].…”

Optimum nutritional strategies for cardiovascular disease prevention and rehabilitation (BACPR)

“…Summary messages regarding dietary protein are presented in table 1. Detailed study7–13 analysis examining protein intake and CVD are presented in online supplementary table 1.…”