Branched-chain Amino Acids (BCAAs) are popular supplements for improving gym and workout performance. The recent prominence of EAAs can be explained by new research and understanding of how BCAAs work.
BCAAs are best for people who already have adequate levels of EAAs in order to facilitate and complete muscle protein synthesis. EAAs, on the other hand, consist of the nine essential amino acids, including BCAAs. EAA supplements are best for people with diet restrictions or people who cannot meet their daily recommended dosages of amino acids.
This article will define and explain BCAAs and EAAs in relation to the process of muscle protein synthesis. It will also discuss the unique role of BCAAs in muscle protein synthesis and why it cannot complete this process without the other EAAs. Lastly, it will explain instances where BCAA intake is sufficient as well as instances where EAA intake is more appropriate.
What are EAAs and BCAAs?
The 20 amino acids are composed of 11 non-essential and 9 essential amino acids. Essential amino acids (EAAs) are the type of amino acids that the body cannot synthesize on its own, but it can get through external means, particularly food.
The nine amino acids are tryptophan, histidine, phenylalanine, threonine, methionine, lysine, valine, leucine, and isoleucine. Among these nine EAAs, the three branched-chain amino acids (BCAAs) are leucine, isoleucine, and valine. These three BCAAs perform the distinct role in cultivating muscle protein synthesis or production of cells for muscle mass gain.
Essentially, BCAAs are also EAAs.
EAAs are crucial elements in muscle protein synthesis, preventing catabolic state or muscle breakdown and spurring muscle recovery after a workout. They also increase the basal metabolic rate (BMR) which is an important factor in weight loss. EAA supplements provide a similar stimulus for growth as whey protein supplements.
Aside from physiological growth, EAAs also perform several assistive functions including: hormone regulation, cognitive and neurological health, metabolism, and enzyme production. EAAs histidine and threonine also help boost the immune system by fighting free radicals and keeping the endocrine system in check. They also promote better mood and sleep.
BCAAs are a particular type of EAA because of their molecular structure. This specific type of EAA contains an aliphatic side chain where a central carbon atom binds to three or more other carbon atoms.
BCAAs valine and isoleucine perform a unique function of providing an alternative energy source for the body during workouts as the body’s glycogen supply is depleted.
People can take EAAs and BCAAs throughout the day, but it is best used as a pre-workout or intra-workout supplement. The effects of amino acids are at its peak 30 minutes after consumption, but the effects also diminish quickly.
Anabolic State vs Catabolic State
The protein in the human body constantly gets broken down as new protein cells emerge. This leads to either muscle growth or muscle breakdown.
When the number of created proteins exceeds the number of broken-down proteins, this leads to an anabolic state where the body facilitates muscle protein synthesis or the creation of more muscle mass.
However, when the number of broken-down protein exceeds the number of created proteins, this causes a catabolic state or muscle protein breakdown where there is a reduction of muscle mass.
Physical exercise shifts the body towards muscle protein breakdown through the tearing of muscle fibers. The amino acids in the body repair the muscle fibers and produce new ones which increases overall muscle mass over time.
Benefits of BCAA
BCAAs provide additional energy supply by enhancing glycogen synthesis as well as glucose uptake by the liver and skeletal muscle. The muscles utilize the circulatory BCAAs in the human body.
The depletion of BCAAs in the body can lead to a reduction of tryptophan supply for the brain. Tryptophan is responsible for promoting good serotonin levels in the brain which improves mood.
It also functions as a modulator of muscle protein synthesis to facilitate muscle recovery and growth after a workout.
The BCAA leucine functions as the trigger for the mammalian target of rapamycin or mTOR pathway which initiates the process of muscle protein synthesis. Taking a minimum of 1.8 grams of leucine during or after workouts can improve the facilitation of muscle protein synthesis.
According to the Essentials of Strength Training and Conditioning, the muscles utilize amino acids better during the first 48 hours after workout. The Frontiers of Psychology also stated that taking BCAAs after a workout can improve muscle protein synthesis by up to 22%.
Aside from supplements, BCAAs can also be acquired through whole foods including meat, poultry, beans, and brown rice. According to McCance and Widdowson, 100g of chicken breast contains 2.44g of isoleucine, 2.34g of leucine, and 1.5g of valine for a total of 5.28g of BCAAs.
New Research on the Drawbacks of BCAAs
Recent studies have discovered certain properties of the BCAAs in relation to the other remaining EAAs. While it is true that BCAAs activate the mTOR to facilitate muscle protein synthesis, EAAs are equally essential to the process of muscle protein synthesis.
The previous rationale for taking BCAA supplements was to supply ample amounts of BCAA sinto the body in order to shorten the catabolic state and transition quickly to the anabolic state.
The previous understanding of the activation of the anabolic state is when the amount of protein generated exceeds the amount of protein broken down. EAAs ensure that protein generated is greater than the protein being broken down which activates the anabolic state.
However, new research has shown that anabolic state can also be activated through inhibiting muscle protein breakdown, which is BCAA’s primary function. New research has also shown that BCAAs perform anabolic signaling through inhibition of muscle protein breakdown. Meaning, the body’s anabolic state requires sufficient amounts of EAAs in the body.
Without a sufficient supply of EAAs in the body, muscle protein synthesis and mass gain will not materialize. To compensate for the lack of circulatory EAAs in the body, BCAAs are forced to catabolize on existing protein in the body to produce EAAs, leading to muscle protein breakdown.
Thus, BCAAs cannot work alone in completing muscle protein synthesis. BCAAs activate the anabolic state through anabolic signaling, but the anabolic process requires EAAs to fuel muscle protein synthesis.
The Journal of the International Society of Sports Nutrition also stated that an abundance of the full spectrum of EAA, rather than BCAAs alone, is necessary for completing muscle protein synthesis.
Are EAAs Better than BCAAs?
The popularity of BCAAs is founded on the assumption that the body usually has enough supply of EAAs as they are easily gained through food. BCAAs are only intended as supplements to facilitate muscle protein synthesis.
However, some people are not able to meet their daily amino acid needs due to an unhealthy diet. Meeting the daily amino acid needs is even more difficult if an individual is on a restrictive diet.
Since animal protein is a richer source of amino acids compared with plant protein, vegans and vegetarians usually miss two or three basic EAAs and therefore need supplementation to meet their amino acid requirements. The average daily dosage for EAAs should be around 10-15 grams per day.
The International Society of Sports Nutrition (ISSN) also stated that active adults weighing around 150 pounds need around 95 to 136 grams of protein per day. People meeting this dietary recommendation usually have sufficient EAAs in their bodies.
People with sufficient EAAs gained through their diet can benefit from using BCAAs as their post- and intra-workout supplement. The EAAs gained through food is enough to prevent the BCAAs from catabolizing existing EAAs in the body.
However, for people who do not meet the ISSN dietary requirement or those who want to work out while fasting, EAAs will provide sufficient EAAs and BCAAs to facilitate and complete muscle protein synthesis.