Substantial evidence has been accumulated suggesting that branched-chain amino acid (BCAA) supplementation or BCAA-rich diets have a positive effect on the regulation of body weight, muscle protein synthesis, glucose homeostasis,( the balance of insulin and glucagon to maintain blood glucose..
Leucine, a branched-chain amino acid (BCAA), has been shown to stimulate muscle protein synthesis, and thus has been proposed to prevent age-related muscle atrophy (sarcopenia). Therefore, leucine supplementation may have potential benefits in elderly populations to preserve muscle mass. The tolerable upper intake level (UL) for leucine intake in young men has recently been determined to be 500 mg /kg of body weight per day.
Leucine supplementation has grown in popularity due to the discovery of its anabolic effects on cell signaling and protein synthesis in muscle. The current recommendation is a minimum intake of 55 mg per kg of body weight per day. Leucine acutely stimulates skeletal muscle anabolism and can overcome the anabolic resistance of aging. The value of chronic leucine ingestion for muscle growth is still unclear. Most of the research into leucine consumption has focused on efficacy.
Leucine, isoleucine and valine, the branched-chain amino acids (BCAA), make up about one-third of muscle protein. Of these, leucine has been the most thoroughly investigated because its oxidation rate is higher than that of isoleucine or valine. Leucine also stimulates protein synthesis in muscle and is closely associated with the release of gluconeogenic precursors, such as alanine, from muscle. Significant decreases in plasma or serum levels of leucine occur following aerobic (11 to 33%), anaerobic lactic (5 to 8%) and strength exercise (30%) sessions. In skeletal muscle, there is a decrease in leucine level and a reduction in glycogen stores during exhaustive aerobic exercise. (running, swimming, cycling, rowing, etc.)
BCAA supplementation (76% leucine) in combination with moderate energy restriction has been shown to induce significant and preferential losses of visceral adipose tissue and to allow maintenance of a high level of performance.