The Branched Chain Amino Acids (BCAAs) include leucine, isoleucine, and valine. The combination of these three makes up about 1/3 of all amino acids in the body and 14% of skeletal muscle tissue. “Branched chain” refers to their chemical structure, which differentiates them from other amino acids. BCAAs are considered to be essential amino acids because the human body cannot produce them and they must be present in the diet.
BCAAs help to maintain muscle tissue and preserve glycogen stores. They are important fuel sources for skeletal muscle during intense exercise or other metabolic stresses. In fact, during stressful periods BCAAs are needed by the body in greater quantities than any other amino acid. Because of their ability to increase protein synthesis and decrease protein breakdown, they help build muscle during and after exercise. Because they are a primary source of energy during exercise, supplemental BCAAs may also extend the time you can exercise before fatigue sets in.
Leucine is required for infant and child growth, and it maintains the nitrogen balance in adults. Leucine also lowers blood sugar levels and contributes to the healing of skin, bones, and muscle tissue. Valine is essential for protein structure and synthesis, as well as glucose synthesis in the liver during anaerobic exercise. Isoleucine produces compounds in the body that contribute to energy production.
Uses and Applications
BCAAs are given to patients after surgery and during chronic illness to improve healing and recovery. They are also useful for the recovery of burn victims, due to their ability to aid in the healing of skin.
All three BCAAs are metabolized in muscle tissue. This means they are highly anabolic or muscle-building, as well as anti-catabolic, meaning they stop the breakdown of muscle. Athletes use BCAAs to maintain their strength and to stimulate the production of new muscle while preventing muscle breakdown.
Supplementation with BCAAs may delay fatigue, improve athletic performance and improve mood and the performance of challenging tasks following intense exercise.
Dietary Sources and dosage
All three BCAAs are found in protein sources, particularly red meat and dairy products. Whey protein and egg also supply BCAAs. Only people who do not consume sufficient protein will be deficient in BCAAs; however athletes may wish to take more. The recommended daily intake is 25-65 mg per kilogram of body weight, depending on stress or physical activity level. Many athletes take 3 to 5 grams of supplemental BCAAs to delay fatigue and improve their performance.
BCAA supplementation at the recommended amounts generally does not have side effects. However, people with medical conditions such as kidney disease or dysfunction, high blood pressure or other blood conditions should not take BCAAs. Check with your doctor to be sure.