The recommended protein intake is at least 0.8 g/kg body weight per day. For older adults who are at risk for frailty, disability, and mortality, the recommended consumption is 1.0 to 1.2 g/kg body weight per day. A study assessed whether target protein intake should be adjusted based on sex or race.
The researchers assessed the associations between sex and race and dietary protein intake in terms of three- and six-year changes in appendicular lean mass and gait speed, as well as six-year incidence of mobility limitation. Data were obtained from the Health, Aging, and Body Composition Study on adults aged 70 to 81 years. A food frequency questionnaire was used to evaluate protein intake. Appendicular lean mass and gait speed were measured at baseline, three years, and six years. Over a six-year period, participants were assessed every six months for difficulty walking a quarter mile or climbing stairs.
Final analysis included 1,163 men and 1,237 women. The mean age of the whole cohort was 74.6 years, and 36.2% of participants were black. Men consumed 71.3 g of protein per day, and women consumed 60.7 g per day. More than one-third of men (39.7%) and women (37.6%) reported a protein intake lower than the recommended 0.8 g/kg of body weight per day. When stratified by age and sex, protein intake was: white men, 0.93 g/kg body weight per day; black men, 0.94 g/kg body weight per day; white women, 0.95 g/kg body weight per day; and black women, 0.95 g/kg body weight per day.
Women with a higher protein intake had less appendicular lean mass loss over a three-year period, and the association was more significant among black women. However, for women, protein intake did not affect appendicula lean mass loss over a six-year period, nor gait speed decline. A higher protein intake in men did not affect changes in appendicular lean mass nor gait speed. Higher protein intake was correlated with a lower risk of mobility limitation in men (adjusted hazard ratio [HR] per 1.0 g/kg body weight per day, 0.55; 95% confidence interval [CI], 0.34-0.91) and women (adjusted HR, 0.56; 95% CI, 0.33 to 0.94), particularly white women.
“More prospective studies with a sex- and race-specific focus are needed to elucidate whether associations between protein intake, muscle mass, and physical function differ by sex and race,” the researchers concluded.