Branched-chain amino acids: the best compromise to achieve anabolism?

Abstract

The anorexia-cachexia syndrome is highly prevalent in patients suffering from acute and chronic diseases, including cancer, chronic renal failure and liver cirrhosis. Once it has developed, it significantly influences the clinical course of the underlying disease, simultaneously impinging on patients' quality of life. Unfortunately, currently available therapeutic strategies do not appear to greatly impact on patients' morbidity, mortality and quality of life. More effective therapies are needed to promote appetite and food intake, to preserve lean body mass, and to ameliorate patients' psychological distress. Branched-chain amino acids are neutral amino acids with interesting and clinically relevant metabolic effects. Their potential role as antianorexia and anticachexia agents was proposed many years ago, but only recent experimental studies and clinical trials have tested their ability to stimulate food intake and counteract muscle wasting in anorectic, weight-losing patients. By interfering with brain serotonergic activity and by inhibiting the overexpression of critical muscular proteolytic pathways, branched-chain amino acids have been shown to induce beneficial metabolic and clinical effects under different pathological conditions. Based on the available data, branched-chain amino acids appear to exert significant antianorectic and anticachectic effects, and their supplementation may represent a viable intervention not only for patients suffering from chronic diseases, but also for those individuals at risk of sarcopenia due to age, immobility or prolonged bed rest, including trauma, orthopedic or neurologic patients.