Amino acids are the building blocks of protein within the body and are involved in the transport and storage of nutrients.
The 20 amino acids that exist can be divided into essential and non-essential, which determines whether they can be produced within the body or not. The body can produce 11 amino acids, and therefore these are termed non-essential, whilst the remaining 9 (essential) must be consumed through the diet. All 20 amino acids are required for the human body to function healthily, with their roles including, but not limited to the production of:
So where do BCAAs come into it?
3 of the essential amino acids; leucine, isoleucine and valine can be further subdivided into branched chain amino acids (BCAAs).
The relevance of these to athletes is that they are primarily broken down in the muscle, as opposed to the liver, and can therefore have a direct impact on the building of new muscle protein.
Additionally, they can also provide a small amount of energy during exercise, which could be crucial when primary energy stores (carbohydrates and fat) are being reduced.
Why are they so important?
To allow your muscles to grow, the rate of muscle protein production must be greater than the rate of breakdown. This is known as your net protein balance, and therefore we want to try and keep this balance in a positive state.
When breakdown is greater than production, a loss in muscle mass would occur, and similarly a balance between the two would result in no change in muscle mass. In order for the net balance to remain positive, the body requires adequate levels of amino acids that can continually turnover new muscle protein, whilst minimising the breakdown. Enter, BCAAs.
(one of the 3 BCAAs) is the key driving force of muscle protein production(1)
, and therefore its presence would result in a greater rate of muscle growth and repair
, important for recovery following a bout of exercise
. This would tip the net protein balance in favour of production, rather than breakdown, essentially leading to more muscle growth
In addition to their primary role of muscle protein production, BCAAs have also shown to reduce muscle soreness following exercise. This is primarily done by minimising the amount of breakdown that the muscle undergoes during exercise.
This is important for young athletes who are training on consecutive days, and would need to recover in order to perform effectively in the next session.
Muscle protein breakdown will occur when amino acid availability drops too low to support the rate of production. Therefore, regular 2-3 hr feedings of protein throughout the day will ensure the net protein balance remains in a positive state.
BCAA's can be found in natural protein sources such as chicken breasts, lean beef mince, salmon and tuna, which is ideal when focusing on a ‘food first approach’.
It is has been shown that 6g of BCAAs is enough to promote muscle protein production(2), which can be found in the average 150 g chicken breast. The supplementation of BCAAs may not have any extra benefits if you consume an adequate amount of protein through your diet each day.
Don’t Forget the Carbs!
The benefits of the co-ingestion of BCAA's and carbohydrates have been seen when consumed both before and after exercise. Carbohydrates are not only important for replenishing energy stores, but they can also help activate the pathway responsible for protein production.
The uptake of BCAA's
into the muscle when mixed with a carbohydrate solution was greater when consumed before, rather than after a resistance session(2)
. This is thought to be due to a greater delivery of amino acids to the muscle due to increased blood flow during exercise.
Likewise, the ingestion of carbohydrates and protein with added leucine following exercise increased net protein balance(3). Therefore, the choice is yours… Just remember your protein timings around your sessions should still align with your 2-3 h feeds.
In summary then, despite their science'y name, BCAA's are natural compounds of proteins, and are thus suitable for athletes of all ages in sport.
About the Author - Adam Salamon holds a BSc. in applied Sport and Exercise and MSc. in Sport Nutrition at Liverpool John Moores University. Adam is also a Performance nutrition intern at Tranmere Rovers FC.
(1). Tipton KD, Wolfe RR. Protein and amino acids for athletes. J Sports Sci. 2004 Jan;22(1):65-79.
(2). Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE, Wolfe RR. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001 Aug;281(2):E197-206.
(3). Koopman R, Wagenmakers AJ, Manders RJ, Zorenc AH, Senden JM, Gorselink M, Keizer HA, van Loon LJ. Combined ingestion of protein and free leucine with carbohydrate increases postexercise muscle protein synthesis in vivo in male subjects. Am J Physiol Endocrinol Metab. 2005 Apr;288(4):E645-53.