King Grub
2017-05-09, 07:51
The age related loss of skeletal muscle mass and function, can lead to loss of independence and is detrimental to metabolic health. The current recommended daily allowance (RDA) for protein intake is 0.8 g/kg/day; both epidemiological and mechanistic evidence suggest that protein intake at this level may not be adequate to maintain skeletal muscle mass in older adults especially during negative energy balance. However, there is limited evidence from randomized controlled trials.
30 healthy older men (BMI: 28.3 ± 0.8 kg/m2, body fat: 27.8 ± 1.4 %, fasting glucose: 5.7 ± 0.1 mmol/L; Mean ± SEM) were randomized to consume protein either at the RDA or at twice the RDA ([2xRDA], 1.6g/kg/day) for ten weeks. Both diets intended to maintain body mass and conformed to U.S. Department of Agriculture guidelines. All meals were provided to the participants. Lean mass and fat mass were measured using Dual-energy X-ray absorptiometry, physical function was assessed by using the short physical performance battery (SPPB) and isometric dynamometry. Compliance was ensured with diet records and analysis of urinary nitrogen excretion.
Appendicular lean mass did not change in 2xRDA (25.0 ± 10.3 kg to 25.2 ± 9.6 kg, P=0.592) but decreased in RDA (24.4 ± 9.9 kg to 23.8 ± 9.3 kg, P=0.005). Whole body lean mass was unchanged in RDA (56.6 ± 21.2 kg to 56.1 ± 20.1 kg, P=0.149), while it increased in 2xRDA (55.7 ± 21.2kg to 57.2 ± 20.2 kg, P<0.001), however, this changes was mostly accounted for by an increase in trunk lean mass (+1.4 ± 0.3 kg, P<0.001). Both groups decreased total body fat mass and body fat percentage similarly. SPPB scores were unchanged in both groups but there was a trend towards an interaction (P=0.077) in isometric knee extension torque such that strength increased in 2xRDA (147.1 ± 17.7 Nm to 154.6 ± 13.4 Nm) and decreased in RDA (158.8 ± 14.2 Nm to 150.1 ± 13.0 Nm).
When older men consume a controlled diet containing protein at currently recommended levels, an observable loss of appendicular lean mass can occur in as little as ten weeks. Higher protein diets may be required to support the maintenance of muscle mass in older adults.
Ten Weeks of Protein Consumption at the RDA Results in a Loss of Appendicular Lean Mass in Healthy Older Men, a Randomized Controlled Trial. April 2017, The FASEB Journal vol. 31 no. 1 Supplement 139.1.
30 healthy older men (BMI: 28.3 ± 0.8 kg/m2, body fat: 27.8 ± 1.4 %, fasting glucose: 5.7 ± 0.1 mmol/L; Mean ± SEM) were randomized to consume protein either at the RDA or at twice the RDA ([2xRDA], 1.6g/kg/day) for ten weeks. Both diets intended to maintain body mass and conformed to U.S. Department of Agriculture guidelines. All meals were provided to the participants. Lean mass and fat mass were measured using Dual-energy X-ray absorptiometry, physical function was assessed by using the short physical performance battery (SPPB) and isometric dynamometry. Compliance was ensured with diet records and analysis of urinary nitrogen excretion.
Appendicular lean mass did not change in 2xRDA (25.0 ± 10.3 kg to 25.2 ± 9.6 kg, P=0.592) but decreased in RDA (24.4 ± 9.9 kg to 23.8 ± 9.3 kg, P=0.005). Whole body lean mass was unchanged in RDA (56.6 ± 21.2 kg to 56.1 ± 20.1 kg, P=0.149), while it increased in 2xRDA (55.7 ± 21.2kg to 57.2 ± 20.2 kg, P<0.001), however, this changes was mostly accounted for by an increase in trunk lean mass (+1.4 ± 0.3 kg, P<0.001). Both groups decreased total body fat mass and body fat percentage similarly. SPPB scores were unchanged in both groups but there was a trend towards an interaction (P=0.077) in isometric knee extension torque such that strength increased in 2xRDA (147.1 ± 17.7 Nm to 154.6 ± 13.4 Nm) and decreased in RDA (158.8 ± 14.2 Nm to 150.1 ± 13.0 Nm).
When older men consume a controlled diet containing protein at currently recommended levels, an observable loss of appendicular lean mass can occur in as little as ten weeks. Higher protein diets may be required to support the maintenance of muscle mass in older adults.
Ten Weeks of Protein Consumption at the RDA Results in a Loss of Appendicular Lean Mass in Healthy Older Men, a Randomized Controlled Trial. April 2017, The FASEB Journal vol. 31 no. 1 Supplement 139.1.