A recent study published in The Journal of Nutrition provides further support that higher protein intake may be an effective strategy for middle-aged men and women to maintain skeletal muscle strength and mass.

Sarcopenia, age-related loss of skeletal muscle mass and strength, increases the risk of falls, fractures, and mortality as well as impaired ability to perform daily activities. Although sarcopenia becomes more apparent with advancing age, it can begin as early as the 4th decade of life. Protein intake predicts skeletal muscle mass and strength among older adults, but knowledge of similar associations among middle-aged adults is lacking. To better understand the relationship between protein intake and markers of sarcopenia among middle-aged adults, Regan Bailey (Purdue University) and colleagues used data from the National Health and Nutrition Examination Survey (NHANES 2011—2014 cycles); a nationwide survey conducted in the United States to assess health and nutritional status.

Protein intake per kilogram of body weight was assessed by two 24-hour dietary recalls.  Dietary data were examined as continuous and categorical parameters: low protein intake (< 0.8 g/kg body weight), moderate protein intake (between 0.8 g/kg and 1.2 g/kg body weight), and high protein intake (> 1.2 g/kg body weight).  Low lean mass and weakness based on handgrip strength were defined using the Foundation of the National Institutes of Health criteria.  Skeletal muscle mass was characterized by appendicular lean mass adjusted for body mass index whereas handgrip strength adjusted for body mass index was used to provide a measure of muscle strength. 

Among middle-aged adults, 15.6% of men and 13.4% of women had low lean mass while 3.5% of men and 2.3% of women exhibited weakness. Based on continuous protein intakes, those with lower protein intake were more likely to exhibit low lean mass and weakness compared to those with higher intakes of protein.  Compared with the moderate protein group, the high protein group had higher muscle strength compared to the low protein group. Study results support the notion that higher protein intake, especially protein intake meeting the Recommended Dietary Allowance of 0.8 g/kg of body weight, is associated with higher skeletal muscle mass and strength among middled-aged men and women. In addition, protein intakes greater than 1.2 g/kg of body weight may exert beneficial effects on muscle strength. However, more rigorous data from longitudinal and intervention studies are important to provide further validation of these findings.


Shinyoung Jun, Alexandra E Cowan, Johanna T Dwyer, Wayne W Campbell, Anna E Thalacker-Mercer, Jaime J Gahche, Regan L Bailey, Dietary Protein Intake Is Positively Associated with Appendicular Lean Mass and Handgrip Strength among Middle-Aged US Adults, The Journal of Nutrition, Volume 151, Issue 12, December 2021, Pages 3755–3763, https://doi.org/10.1093/jn/nxab288.

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