Many experts in nutrition recommend a higher intake of protein for older adults. However, few rigorous studies have evaluated whether this provides any meaningful benefit.
A new randomised, clinical trial conducted by Brigham and Women’s Hospital has found that higher protein intake does not increase lean body mass, muscle performance or physical function in older men. The study has been published in JAMA Internal Medicine.
The study’s corresponding author, Shalender Bhasin, said: ’It’s amazing how little evidence there is around how much protein we need in our diet, especially the value of high-protein intake. Despite a lack of evidence, experts continue to recommend high-protein intake for older men. We wanted to test this rigorously and determine whether protein intake greater than the recommended dietary allowance is beneficial in increasing muscle mass, strength and wellbeing.’
During the randomised, placebo-controlled, double-blind trial, men over the age of 65 received a diet containing 0.8-g per kg a day protein and a placebo injection; 1.3-g per kg a day protein and a placebo injection; 0.8-g per kg a day protein and a weekly injection of testosterone; or 1.3-g per kg a day protein and a weekly injection of testosterone. All participants were given prepackaged meals with individual protein and energy contents and supplements. Seventy-eight participants completed the six-month trial.
The team found that protein intake greater than the RDA had no significant effect on lean body mass, fat mass, muscle performance, physical function, fatigue or other well-being measures.
‘Our data highlight the need for re-evaluation of the protein recommended daily allowance in older adults, especially those with frailty and chronic disease,’ the authors concluded.