Dietary treatment of rheumatoid cachexia with β-hydroxy- β-methylbutyrate, glutamine and arginine: A randomised controlled trial

Abstract

Background & Aims Rheumatoid arthritis (RA) is complicated by cytokine-driven alterations in protein and energy metabolism and consequent muscle wasting (cachexia). The aim of this randomised controlled trial was to investigate the efficacy of a mixture of β-hydroxy-β-methylbutyrate, glutamine and arginine (HMB/GLN/ARG) as nutritional treatment for rheumatoid cachexia. Methods Forty RA patients supplemented their diet with either HMB/GLN/ARG or a nitrogen (7.19g/day) and calorie (180kcal/day) balanced mixture of alanine, glutamic acid, glycine, and serine (placebo) for 12 weeks. Body composition and other outcomes were assessed at baseline and follow-up, and analysed by mixed ANOVA. Results Dietary supplementation with HMB/GLN/ARG was not superior to placebo in the treatment of rheumatoid cachexia (group×time interactions P > 0.05 for all outcomes). Both amino acid mixtures significantly increased (main effect of time) fat-free mass (727±1186g, P < 0.01 ), total body protein (719±1703g, P = 0.02 ), arms (112±183g, P < 0.01 ) and legs (283±534g, P < 0.01 ) lean mass, and some measures of physical function. No significant adverse event occurred during the study, but patients in the HMB/GLN/ARG group reported fewer gastrointestinal complaints compared to placebo. Conclusions Dietary supplementation with HMB/GLN/ARG is better tolerated but not more effective in reversing cachexia in RA patients compared to the mixture of other non-essential amino acids used as placebo. Further controlled studies are necessary to confirm the beneficial anabolic and functional effects of increased nitrogen intake in this population. Rheumatoid arthritis (RA) is complicated by cytokine-driven alterations in protein and energy metabolism and consequent muscle wasting (cachexia). The aim of this randomised controlled trial was to investigate the efficacy of a mixture of β-hydroxy-β-methylbutyrate, glutamine and arginine (HMB/GLN/ARG) as nutritional treatment for rheumatoid cachexia. Forty RA patients supplemented their diet with either HMB/GLN/ARG or a nitrogen (7.19g/day) and calorie (180kcal/day) balanced mixture of alanine, glutamic acid, glycine, and serine (placebo) for 12 weeks. Body composition and other outcomes were assessed at baseline and follow-up, and analysed by mixed ANOVA. Dietary supplementation with HMB/GLN/ARG was not superior to placebo in the treatment of rheumatoid cachexia (group×time interactions P > 0.05 for all outcomes). Both amino acid mixtures significantly increased (main effect of time) fat-free mass (727±1186g, P < 0.01 ), total body protein (719±1703g, P = 0.02 ), arms (112±183g, P < 0.01 ) and legs (283±534g, P < 0.01 ) lean mass, and some measures of physical function. No significant adverse event occurred during the study, but patients in the HMB/GLN/ARG group reported fewer gastrointestinal complaints compared to placebo. Dietary supplementation with HMB/GLN/ARG is better tolerated but not more effective in reversing cachexia in RA patients compared to the mixture of other non-essential amino acids used as placebo. Further controlled studies are necessary to confirm the beneficial anabolic and functional effects of increased nitrogen intake in this population.