When it comes to building muscle, branched-chain amino acids (BCAAs) are a popular supplement. However, most people don’t understand the science or reasoning behind consuming BCAAs, they just know that they’re beneficial for those that workout.
Three of the nine essential amino acids are also known as branched-chain amino acids. These are the real rockstars for building protein within the human body. These proteinogenic (meaning protein building) essential amino acids are leucine, isoleucine, and valine. As a chemical structure, they are aliphatic side chains with a branch -- hence the name branched-chain.
BCAAs have a few purposes: increasing amino acid levels in the bloodstream, promoting muscle protein synthesis, and preventing muscle protein breakdown. After consumption, BCAAs will still stimulate muscle protein synthesis in almost all situations.
What is incredible about these amino acids, is not only are they beneficial for an athlete recovering from a training session, but these three essential amino acids also stimulate muscle protein synthesis for an injured athlete with a prolonged rest period who is unable to train to help prevent muscular atrophy (breakdown) or older adults experiencing sarcopenia (muscle breakdown related to aging).
The most well-known BCAA that most people talk about is leucine. Leucine is extremely helpful in healing wounds and injuries, and also supports the balancing blood sugar. It provides energy and is essential for growth as a stimulator for protein synthesis in muscle building.
One of the most interesting things about leucine is that it can actually make an inefficient, poor-quality protein even better by stimulating muscle protein synthesis.
Leucine can naturally be found in animal protein, dairy products, oats, and wheat germ. It is recommended to consume at least 2.5 - 3 grams of leucine per meal, and at least 8g of leucine daily.
Like leucine, valine is also very important for muscle building. It is responsible for promoting muscle growth, tissue repair, and preventing muscle breakdown. Valine is also extremely important for proper cognitive function.
Valine can be found within grains, dairy products, animal protein, mushrooms, soy products, as well as peanuts.
Isoleucine is the BCAA that contributes to the biological process that provides the body with energy. This BCAA also participates in hemoglobin synthesis and regulates blood sugar.
Isoleucine is most abundant in chicken, fish, cheese, lentils, eggs, and most seeds and nuts.
Breaking Down Amino Acids and BCAAs in the Body
If you were eating a piece of chicken there is a protein unfolding process in the stomach, which breaks down the protein’s polypeptide chains into smaller peptides, and from there into amino acid chains, and finally into single amino acids. This process occurs in the stomach and first part of the small intestine over a period of time. The length of this process depends on the type of food that was consumed and what else was consumed with it.
Once the unfolding process is complete via digestion in the stomach and small intestine, the amino acids start to be absorbed as they continue throughout the the small intestine (including the duodenum, jejunum, and ileum). Depending on each food, this process occurs over a minimum of three hours.
Although an athlete does focus on a balanced diet, it is common for athletes to combine all three BCAAs in a supplement form. With this in mind, let’s take a look at amino acids consumed as a supplement.
Unlike whole foods, BCAAs do not require the unfolding process in the stomach that turns protein into polypeptide chains and then into single amino acids in the small intestine. Instead, they are passed directly into small intestine where they can be absorbed. This allows for a much faster absorption rate of BCAAs.
Therefore, BCAAs are able to promote muscle growth and to supply athletes with the energy their bodies require at a much faster rate than any whole foods could.