August 31, 2015
Circulation: Heart Failure
TAKE-HOME MESSAGE
- This double-blind trial randomized 31 heart failure (HF) patients to receive either L-alanyl-L-glutamine (8 g/d) and ω-3 polyunsaturated fatty acids (PUFA; 6.5 g/d) or placebo for 3 months to examine the effects of PUFA and glutamine supplementation on exercise performance and muscle protein balance. No significant differences in muscle function, echocardiography, 6-minute walk test, or hand-grip strength test were found between the two groups. While also not significant, peak VO2 increased in the treatment group. The active treatment group did have increased lean body mass and improved quality of life compared with the placebo group.
- Supplementation with L-alanyl-L-glutamine and fish oil in HF patients did not improve exercise performance or muscle function, but did result in an increased lean body mass and an improved quality of life.
Abstract
BACKGROUND
Skeletal muscle dysfunction and exercise intolerance are clinical hallmarks of patients with heart failure (HF). These have been linked to a progressive catabolic state, skeletal muscle inflammation and impaired oxidative metabolism. Prior studies suggest beneficial effects of ω-3 polyunsaturated fatty acids (PUFAs) and glutamine on exercise performance and muscle protein balance.
METHODS AND RESULTS
In a randomized double-blind, placebo-controlled trial, 31 HF patients were randomized to either L-alanyl-L-glutamine (8g/d) and PUFA (6.5g/d) or placebo (safflower oil and milk powder) for 3 months. Cardiopulmonary exercise testing, dual-energy X-ray absorptiometry, 6 minute walk test, hand grip strength, functional muscle testing, echocardiography and quality of life and lateral quadriceps muscle biopsy were performed at baseline and at follow-up. Oxidative capacity and metabolic gene expression were analyzed on muscle biopsies. No differences in muscle function, echocardiography, 6 minute walk test or hand grip strength and a non-significant increase in peak VO2 in the treatment group were found. Lean body mass increased and quality-of-life improved in the active treatment group. Molecular analysis revealed no differences in muscle fiber composition, fiber cross sectional area, gene expression of metabolic marker genes (PGC-1α, CPT1, PDK4, GLUT4) and skeletal muscle oxidative capacity.
CONCLUSIONS
The combined supplementation of L-alanyl-L-glutamine and PUFA did not improve exercise performance or muscle function but increased lean body mass and quality-of-life in patients with chronic stable HF. These findings suggest potentially beneficial effects of high dose nutritional PUFAs and amino acid supplementations in patients with chronic stable HF.