Effects of supplemental protein in older people: an overview of meta-analyses

Benefits of supplemental protein in older people in different health states and settings are uncertain. This review aimed to determine the effects of supplemental protein on health outcomes in older people.

An overview of reviews. Cochrane Library, MEDLINE (Ovid), EMBASE (Ovid), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCOhost) and Google Scholar were searched from January 1990 to August 2024. Systematic reviews with meta-analyses reporting protein intake's effect on health outcomes were included. Methodological quality was assessed using the Assessing Methodological Quality of Systematic Reviews 2 critical appraisal tool. Inconsistency between results from different reviews was explored by examining effects by population type [healthy people, living with long-term conditions (LTCs), hospital inpatients] and whether supplementation was given with or without concomitant exercise.

Thirty-three reviews with meta-analyses collating data from 441 unique studies were included. There was no increase in muscle mass, strength or physical performance from protein supplementation in older people in general, nor in healthy older people. There was medium-certainty evidence of at least small increases in muscle mass and strength in older people with LTCs, and the benefits of protein supplementation were more certain with concomitant exercise. Evidence suggests that protein supplementation in hospital patients with hip fractures reduced the number of medical complications.

Protein supplementation is effective for improving muscle mass and strength in older people with LTCs and medical complications in older hospitalised patients with hip fractures. The evidence does not support its routine use in other groups of healthy older people.