Introduction: What are BCAAs?
BCAAs or Branched Chain Amino Acids, are a group of amino acids found in a variety of foods as part of proteins. They are also sold as supplements and have a number of claimed benefits.
What are amino acids and what are they made of?
There are 20 amino acids that are normally found in the diet, which combine together into ‘chains’ to form proteins. Amino acids are effectively the building blocks of protein, and when protein is consumed and digested, it is these amino acids that are absorbed and will form new proteins in the body. These proteins then have various functions. BCAAs is the collective name for a group of three individual amino acids - leucine, isoleucine and valine, which all share a similar ‘branch’ in their molecular structure (hence the name).
What are essential and non-essential amino acids and what makes one different from the other?
Some of the amino acids we require can be produced in the body, which are known as ‘non-essential’ amino acids. Others cannot be made in the body, and must be consumed from the diet, and are known as ‘essential’ amino acids’. Of the 20 amino acids, 11 are non-essential, whilst 9 are essential (and the three BCAAs are all essential).
Any activity where it is not easy to talk will rely heavily on carbohydrates.
Research into BCAAs
There have been many claims for BCAA supplementation being beneficial, though as a rule the claims are not well supported by the scientific research
- BCAAs are claimed to be important for stimulation of muscle protein synthesis. This process is essential to the process of adapting and improving after training. Whilst it has been shown that a ~6g dose of BCAAs does increase muscle protein synthesis, this was only to around half the level that an equivalent amount of protein does. Therefore, simply eating enough high-quality protein is probably enough to provide all of the recovery benefits.
- It has been shown that BCAAs can be effective at decreasing subjective feelings of muscle soreness 2-3 days after a muscle-damaging resistance exercise session. However, they did not improve functional recovery (strength) in the days after, so the benefits to total recovery after an intense training session are quite modest.
- Consuming BCAAs during endurance exercise is sometimes claimed to reduce feelings of tiredness through effects on the brain. However, there is no evidence that BCAAs can reduce sensations of fatigue compared to a placebo and in studies BCAAs have failed to improve exercise performance. By comparison, ingesting some carbohydrate types (such as a drink or gel) during exercise can significantly reduce feelings of fatigue compared to a placebo (though via different mechanisms) and improve performance.
BCAAs are inferior to simply eating a source of protein (containing all essential amino acids, and therefore the BCAAs) and there is insufficient evidence to recommend using BCAA supplements, despite their wide availability and broad claims of effectiveness.
- Jackman SR, Witard OC, Philp A, Wallis GA, Baar K, Tipton KD. Branched-Chain Amino Acid Ingestion Stimulates Muscle Myofibrillar Protein Synthesis following Resistance Exercise in Humans. Front Physiol. 8:390, 2017.
- Jackman M, Witard OC, Jeukendrup AE, Tipton KD. Branched-chain amino acid ingestion can ameliorate soreness from eccentric exercise. Med Sci Sports Exerc. 42(5):962-70, 2010.
- Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. Journal of Sports Science. 29 (Suppl 1):17-27, 2011.