title: Role of specific dietary amino acids in clinical conditions.
abstract: In a variety of chronic and acute disease states, alterations in protein synthesis, breakdown and protein turnover rates occur that are related to the loss of body protein and skeletal muscle wasting. A key observation is the stimulation of protein breakdown in muscle and the stimulation of protein synthesis in the splanchnic area; mainly liver. An altered splanchnic extraction of amino acids as well as an anabolic resistance to dietary protein, related to stress, disuse and aging play a key role in the pathogenesis of muscle wasting in these conditions. To overcome these factors, specific dietary protein and amino acid diets have been introduced. The main focus of these diets is the quantity and quality of dietary proteins and whether a balanced mixture or solely dietary essential amino acids are required with or without higher intake levels of specific amino acids. Specifically in cancer patients, stimulated muscle protein synthesis has been obtained by increasing the amount of protein in a meal and by providing additional leucine. Also in other chronic diseases such as chronic obstructive pulmonary disease and cystic fibrosis, meals with specific dietary proteins and specific combinations of dietary essential amino acids are able to stimulate anabolism. In acute diseases, a special role for the amino acid arginine and its precursor citrulline as anabolic drivers has been observed. Thus, there is growing evidence that modifying the dietary amino acid composition of a meal will positively influence the net balance between muscle protein synthesis and breakdown, leading to muscle protein anabolism in a variety of chronic and acute disease states. Specific amino acids with anabolic potential are leucine, arginine and citrulline.
authors.affiliation: Department of Health & Kinesiology, Texas A&M University, Suite #210, 1700 Research Parkway, College Station, Texas 77843-4253, USA.
authors.forename: Renate
authors.initials: R
authors.lastname: Jonker
authors.forename: Mariëlle P K J
authors.initials: MP
authors.lastname: Engelen
authors.forename: Nicolaas E P
authors.initials: NE
authors.lastname: Deutz
mesh_terms: D000596:Amino Acids / Q000378:metabolism / Q000627:therapeutic use*; D000601:Amino Acids, Essential / Q000378:metabolism / Q000627:therapeutic use; D003550:Cystic Fibrosis / Q000150:complications / Q000378:metabolism / Q000473:pathology; D004044:Dietary Proteins / Q000378:metabolism / Q000627:therapeutic use*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009140:Musculoskeletal Diseases / Q000178:diet therapy* / Q000209:etiology / Q000378:metabolism; D009369:Neoplasms / Q000150:complications / Q000378:metabolism / Q000473:pathology; D014176:Protein Biosynthesis; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000378:metabolism / Q000473:pathology
chemical_list: D000596:Amino Acids; D000601:Amino Acids, Essential; D004044:Dietary Proteins; D009124:Muscle Proteins