Protein Requirements and Recommendations for Older People: A Review.

Caryl Nowson,Stella O'Connell

doi:10.3390/nu7085311

Abstract

Declines in skeletal muscle mass and strength are major contributors to increased mortality, morbidity and reduced quality of life in older people. Recommended Dietary Allowances/Intakes have failed to adequately consider the protein requirements of the elderly with respect to function. The aim of this paper was to review definitions of optimal protein status and the evidence base for optimal dietary protein. Current recommended protein intakes for older people do not account for the compensatory loss of muscle mass that occurs on lower protein intakes. Older people have lower rates of protein synthesis and whole-body proteolysis in response to an anabolic stimulus (food or resistance exercise). Recommendations for the level of adequate dietary intake of protein for older people should be informed by evidence derived from functional outcomes. Randomized controlled trials report a clear benefit of increased dietary protein on lean mass gain and leg strength, particularly when combined with resistance exercise. There is good consistent evidence (level III-2 to IV) that consumption of 1.0 to 1.3 g/kg/day dietary protein combined with twice-weekly progressive resistance exercise reduces age-related muscle mass loss. Older people appear to require 1.0 to 1.3 g/kg/day dietary protein to optimize physical function, particularly whilst undertaking resistance exercise recommendations.

Highlights

The National Health and Medical Research Council (NH & MRC) Recommended DietaryIntakes for Australians incorporate a small increase in dietary protein requirement for older people over the age of seventy years [1]
There has been some debate regarding the recommended dietary protein intake for older people and it has been proposed that dietary protein intakes which are considerably higher than the minimum protein requirements may be required for optimal health, in older people [4]
There is emerging data that optimal health for older people depends on maintaining muscle mass, which requires greater than minimal amounts of dietary protein [6]

Summary

Introduction

Intakes for Australians incorporate a small increase in dietary protein requirement for older people over the age of seventy years [1]. This is not a consistent dietary recommendation across all countries, as national dietary protein requirements often do not differ across the adult age range [2,3]. There is emerging data that optimal health for older people depends on maintaining muscle mass, which requires greater than minimal amounts of dietary protein [6]. It is increasingly being recognized that more robust methods are required for measuring protein requirement and that the results from short-term nitrogen balance studies can provide only limited information on dietary protein requirements of older people [7]

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Conclusion