Role of nutrition in attenuating muscle loss
Several nutritional strategies have been proposed to counteract muscle loss in critical illness . Two small randomised trials from Australia indicate greater protein doses reduce ultrasound-derived muscle loss 11 , 12 . Further , a study by McNelly et al found bolus , when compared to continuous , feeding achieved protein adequacy more often ; however , no significant effect on muscle loss was evident 13 .
Other potential strategies include branched-chain amino acids , such as leucine , which has great potential to stimulate muscle protein synthesis 14 , 15 ; however , long-term leucine supplementation has failed to show benefit on muscle mass in other populations 16 , 17 . Recently , beta-hydroxybeta-methylbutyrate ( HMB ) – a leucine derivative – has gained attention as a potential therapy to prevent muscle loss . A systematic review by Bear et al reported modest benefits of HMB on muscle mass and strength in populations experiencing muscle loss or weakness 18 .
Further evaluation of nutritional strategies with potential to attenuate muscle loss in ICU or stimulate muscle gain post-ICU are required .
IN SUMMARY :
• Rates of muscle protein breakdown exceed those of muscle protein synthesis in critical illness , leading to muscle loss .
• Nutrition delivery in ICU and on the hospital ward is often inadequate .
• Greater protein dose , bolus versus continuous enteral feeding , branched chain amino acids ( leucine ) and their derivatives ( HMB ) have been posed as potential nutritional strategies to attenuate muscle loss in ICU , but further data is required .
© Dietitian Connection 32 Infuse | May 2021