Alanine increases muscle carnosine levels and delays fatigue

Alanine and carnosine are important chemicals within the muscles that influence muscle size and metabolism. Alanine is an amino acid that provides energy during exercise and counteracts neuromuscular fatigue by increasing muscle carnosine levels. Carnosine is a dipeptide (a molecule consisting of two amino acids) found in meat and is made up of the amino acids alanine and histidine. It is found in many types of tissue in the body, including skeletal muscle and smooth muscle within the arteries. Carnosine is also an important antioxidant that protects the body's cells from oxidative damage, and it also serves as a buffer for acids that cause muscle fatigue. It is crucial for protein synthesis and degradation and may help prevent nerve degeneration and diabetes. A few months ago, we reported that beta-alanine supplementation increased the isometric endurance capacity of the thigh by increasing the muscle's carnosine levels. (Amino Acids, 32: 225-233, 2007). A study from Belgium found that beta-alanine (4.8 grams per day for four weeks) increased muscle carnosine levels by 16% and prevented fatigue during repeated bouts of high-intensity knee extensions, but had no effect on isometric endurance or 400-meter sprint times. Beta-alanine enhances performance in intensely training bodybuilders and other athletes.
(Journal Applied Physiology, in press, published online August 9)