Association between adequate protein intake and quadriceps quantity and quality during rehabilitation in people with subacute stroke

Background We aimed to investigate the association between protein intake and quadriceps quantity and quality on the paretic and non-paretic sides during rehabilitation in people with subacute stroke. Method Eighty-six people with stroke were recruited from a rehabilitation ward. We measured quadriceps muscle quantity and quality on the paretic and non-paretic sides using ultrasonography at admission and after 4weeks. Protein intake was assessed 2 or 3weeks after admission, and participants were classified into two groups: adequate and inadequate protein intake groups. Analysis of covariance was used to determine the effects of protein intake on quadriceps muscle quantity and quality. Results The mean age (standard deviation), median interval between stroke onset and admission (interquartile range) and male proportion of the study participants were 67.6 (13.5) years, 22.5 (16.8-31.3) days, and 54.7%, respectively. The adequate protein intake group showed significantly greater improvements in paretic-side quadriceps thickness than the inadequate group (group-by-time interaction, F =8.771, P =0.004). In contrast, no significant interactions were observed in quadriceps thickness on the non-paretic side (F =2.383, P =0.127) and quadriceps echo intensity on both sides (paretic-side: F =0.020, P =0.887, non-paretic side: F =0.181, P =0.672). Conclusions Adequate protein intake may be useful for improving quadriceps quantity on the paretic side in people with subacute stroke undergoing rehabilitation. However, quadriceps quantity on the non-paretic side and quadriceps quality on both sides were not significantly associated with adequate protein intake.