2 RESEARCH ARTICLES
Isanejad M1, Mursu J1, Sirola J2, Kröger H2, Rikkonen T3, Tuppurainen M4, Erkkilä AT
– Dietary protein intake might be beneficial to physical function (PF) in the elderly
– 554 women aged 65·3-71·6 years belonging to the Osteoporosis Risk Factor and Prevention Fracture Prevention Study
1. At the baseline, women with higher protein intake (≥ 1·2 g/kg BW) had better performance in hand-grip strength/body mass (GS/BM), knee extension/BM, one-leg stance, chair rise, squat, squat to the ground, faster walking speed for 10 m and higher short physical performance battery score compared with those with moderate and lower intakes (0·81-1·19 and ≤ 0·8 g/kg BW, respectively).
2. In follow-up results, higher protein intake was associated with less decline in GS/BM, one-leg stance and tandem walk for 6 m over 3 years.
3. Overall, results were no longer significant after controlling for FM.
4. Associations were detected between protein intake and PF in non-sarcopaenic women but not in sarcopaenic women, except for change of GS.
5. Further, FM but not LM was negatively associated with PF measures.
– This study suggests that higher protein intake and lower FM might be positively associated with PF in elderly women.
Rafii M1, Chapman K1, Owens J1, Elango R2, Campbell WW3, Ball RO4, Pencharz PB5, Courtney-Martin G
(1) 12 subjects, with protein intakes ranging from 0.2 to 2.0 g ⋅ kg-1 ⋅ d-1 for a total of 82 studies
(2) The diets provided energy at 1.5 times each subject’s resting energy expenditure and were isocaloric
(3) Protein was given as an amino acid mixture on the basis of the egg protein pattern, except for phenylalanine and tyrosine, which were maintained constant across the protein intake amounts
(4) All subjects were adapted for 2 d before the study day to a protein intake of 1.0 g ⋅ kg-1 ⋅ d-1
– The mean [estimated average requirement (EAR)] and upper 95% CI (approximating the RDA) protein requirements were estimated to be 0.96 and 1.29g⋅kg⋅d, respectively
– Results are higher than current EAR and RDA based on nitrogen balance, which are 0.66 and 0.80 g⋅kg⋅d, respectively