In September of 2024, we presented an article highlighting the pro’s and cons of creatine use for serious bodybuilders. This month, we continue our series on sports supplementation with a detailed look at branched-chain amino acids, more commonly referred to as BCAAs. Read on to learn about their diverse and potent abilities to enhance any intense muscular or endurance workout.
Protein: The Anabolic Ally
When working with clients, trainers often encounter individuals seeking to “tone up” or “get in better shape”. These phrases most likely describe about 90% of gym members. Those who seek to cultivate a true bodybuilder’s physique, however, tend to proceed in a very different manner. Adding lean muscle mass properly requires dedication not only in the gym, but in the kitchen as well.
This author can speak from personal experience regarding the difficulties associated with consuming lean protein in the vast amounts required to successfully compete in bodybuilding. Even with a keen eye on meal preparation, many aspiring athletes find themselves falling short at the end of each day. In this case, supplementation can serve as a valuable tool.
Amino acids, known as the building blocks of protein, figure prominently when designing a mass-gaining regimen. Of the 20 amino acids required to build a complete protein source, scientists categorize only 9 of these as essential, meaning the human body lacks the ability to synthesize them; therefore, one must consume them through nutritional sources. They include phenylalanine, valine, tryptophan, threonine, isoleucine, methionine, histidine, leucine, and lysine. Of these 9, sports nutrition experts and scientists tend to hone in on only 3: leucine, isoleucine and valine, categorized as branched-chain amino acids (BCAAs).
Definitive Structures and Metabolism
Branched-chain amino acids have amassed quite a bit of popularity during the last few decades, mostly due to their effects (and common use) within the bodybuilding community. We now know that BCAAs go far beyond simply serving as building blocks for muscle tissue; they can also affect muscle growth through some rather unique pathways in the body.
The name “branched-chain amino acids” comes from the structure of these compounds. Each one boasts a specific forked outcropping that resembles a branch. BCAAs comprise roughly a third of the total amount of amino acids found within muscle tissue.
The unique metabolic processes of BCAAs allow them to impact nearly every aspect of serious strength training. Countless studies designate them as powerful performance enhancers, and as previously mentioned, BCAAs themselves serve as wonderful energy sources for working muscles. While most amino acids face metabolism within the liver, muscle tissues primarily serve as the locations for BCAA metabolism. This allows for oxidation of the BCAAs to produce cellular energy in the form of adenosine triphosphate, or ATP. ATP serves as the human body’s primary source of energy for fueling muscle contractions.
Energy and the Sparing of Glycogen
BCAAs also shine as performance enhancers through their ability to spare glycogen during heavy training. Glycogen, which gets stored in the liver as a result of carbohydrate consumption, serves as a preferred fuel source for working muscles engaged in high-intensity exercise. When athletes head to the gym planning on a longer workout session than usual, glycogen availability and preservation will play a vital role in their energy stores.
Studies have linked a significant increase in BCAA metabolism with prolonged exercise, since the body requires more energy during periods of stress brought on by intense training. For this specific reason, many athletes choose to supplement with BCAAs during the peak performance point of their workouts. Data have revealed that the ingestion of BCAAs before and during training can elicit and even boost he sparing of glycogen levels by 25%. Experts speculate that the ingestion of BCAAs leads to an increase in blood alanine levels; this substance, in turn, gets converted to glucose in the liver. At this juncture, the glycogen can henceforth return to working muscles and get utilized as fuel. This glycogen sparing effect of BCAAs will not only allow for prolonged and more intense training sessions, but also speeds up/enhances recovery time. A fully recovered body can promote a more successful workout the following day.
BCAAs Also Compliment Endurance Training
Not only can BCAAs be used as energy themselves; they also enhance fat oxidation in athletes who may find themselves glycogen-depleted, as often occurs during a marathon. This allows individuals to train harder for longer without experience overwhelming fatigue brought on by the higher energy demands.
The Duality of Leucine and Glutamine
The amino acids glutamine and leucine work together to offer a muscle tissue signaling effect on synthesis. Glutamine seems to direct the largest response; however, it often proves ineffective in the absence of sufficient quantities of circulating leucine in the body.
Leucine acts directly upon stimulation of protein synthesis through the activation of insulin. Insulin plays the vital role of increasing the uptake of all amino acids into the body’s cells.
While BCAAs primarily serve muscle tissues for energy, the incorporation of BCAAs directly into muscle lies in the power of insulin-like growth factor, or IGF-1. IGF-1 stimulates muscle tissue synthesis, while insulin inhibits the breakdown of muscle and encourages the uptake of amino acids (including BCAAs).
The Signaling of mTOR
Within recent years, scientists have found that BCAAs in general, and leucine in particular, send signals to the body that inform and facilitate the building of muscle. One of the ways leucine works to signal muscle growth comes via its unique interaction with mammalian target of rapamycin, or mTOR. Located directly within the cells and responsible for detecting an excess of amino acids, mTOR plays a key role in regulating hypertrophy, or muscle growth. Scientists continue to delve into the specifics of this process, but it seems as though the mTOR pathway shows extreme sensitivity to the amino acid leucine. Recent tests have shown that when consumed orally, leucine activates mTOR which then jump-starts protein synthesis and hence muscular growth. In addition, this elicits an uptick in a cell’s capacity to produce new proteins (muscle tissue).
Dosage Suggestions
A colleague of mine dedicated his PhD research to the actions of the amino acid leucine, owing in large part to the manner in which this particular amino acid seems to dictate so much of what happens within muscle tissues. Athletes who take the time to do some research on BCAAs sometimes wonder why they should take all 3 BCAAS, if leucine seems to have exhibited the greatest potential for eliciting muscle growth. This reasonable proposition has a very good answer. Studies consistently demonstrate that more protein synthesis occurs when one consumes a 2:1:1 ratio of leucine, isoleucine, and valine. When taken alone, leucine may actually diminish the concentrations of the other two amino acids.
While BCAAs can certainly help to orchestrate and signal muscle growth, the body must contain a full spectrum of amino acids in order for the BCAAs to act as the substrate for muscle growth. This serves as a reminder to serious athletes to continue consuming adequate amounts of whole lean protein in addition to their supplementation. Lean beef, poultry, fish, low-fat dairy products, tofu and eggs serve as excellent protein sources to round out a bodybuilder’s menu, of course in conjunction with fresh vegetables and whole grains.
Holding Onto Muscle During a Leaning Phase
BCAAs can serve a very important supplemental role during any fat loss plan, due to their muscle-preserving abilities. Whenever a bodybuilder enters into any calorie-restricted phase of training, typically in the weeks leading up to a competition, the potential does exist for muscle tissue loss, a serious concern after months of hard work and dedication. All of the positive effects that BCAAs demonstrate on muscle growth will similarly serve to protect hard-earned muscle mass in periods of calorie restriction.
Bottom Line
Some bodybuilders and athletes turn to dietary supplements in an attempt to improve their strength, muscle mass, and energy. However, these products do not necessarily come under FDA scrutiny, nor have firm standards been established. Some of them may contain ingredients that have not been proven effective or hold the potential to harm one’s health. Here we offer a few key points to bear in mind regarding dietary supplements marketed for bodybuilding or performance enhancement ~
- Some bodybuilding products contain dangerous hidden ingredients. As is the case with so many supplements on today’s market, consumers may unknowingly take products laced with prescription drug ingredients, controlled substances, or other ingredients not listed on the label. Bodybuilding supplements may contain trace amounts of anabolic steroids—modified male hormones designed to increase muscle mass. Anabolic steroids will not pass urine testing for those bodybuilders competing in a “natural” show, rendering the user disqualified from competition. While these substances can boost strength, the litany of potential long-term side effects contains some frightening facts, such as early heart attacks, strokes, liver tumors, kidney failure, and psychiatric problems. Stopping use too abruptly, and without properly tapering the dosage, can often lead to depression.
- Products containing stimulants such as BMPEA or DMAA can cause serious health problems. Supplements containing the herb Acacia rigidula often contain β-methylphenylethylamine (BMPEA), which in not naturally occurring in the herb nor is it a regulated dietary ingredient. The dosage of the amphetamine isomer BMPEA may exceed that which falls under safety guidelines.
- Take charge of your health. Prior to selecting/consuming any dietary supplement for athletic performance, always consult with a trained and knowledgeable health care provider. Together, you can make well-informed decisions.
References:
https://www.muscleandstrength.com/articles/8-muscle-building-essentials
https://www.muscleandstrength.com/expert-guides/bcaas
https://pubmed.ncbi.nlm.nih.gov/28638350/
https://pubmed.ncbi.nlm.nih.gov/31250889/
https://www.huhs.edu/literature/BCAA.pdf
Cathleen Kronemer is an NFPT CEC writer and a member of the NFPT Certification Council Board. Cathleen is an AFAA-Certified Group Exercise Instructor, NSCA-Certified Personal Trainer, ACE-Certified Health Coach, former competitive bodybuilder and freelance writer. She is employed at the Jewish Community Center in St. Louis, MO. Cathleen has been involved in the fitness industry for over three decades. Feel free to contact her at trainhard@kronemer.com. She welcomes your feedback and your comments!
