by Charles Poliquin
One of the most effective ways to be lean and strong for life is to familiarize yourself with the branched-chain amino acids (BCAAs). A few of the most compelling reasons to know about BCAAs include the following:
- BCAA metabolites were found to be a significant indicator of lean mass in a population of young and middle-aged adults.
- People who consume a threshold dose of essential amino acids that contain BCAAs with every meal have less visceral belly fat and more muscle mass.
- BCAAs trigger protein synthesis and inhibit the breakdown of muscle cells.
- In healthy people, BCAAs improve glucose uptake and insulin sensitivity. In diabetics, BCAA dietary intake with other therapeutic interventions may improve metabolic markers.
- BCAAs play an important role in muscle and energy production during exercise, which is the reason that they are often used during workouts.
- BCAAs convey many health benefits and a higher dietary intake has been identified as a predictor of longevity.
- They have ben found to reduce muscle soreness from intense muscle-damaging exercise.
- They improve training motivation, especially when fatigued.
The Basics of BCAAs
The BCAAs are made up of three essential amino, leucine, isoleucine, and valine. They are essential because the body is unable to make them out of other amino acids, meaning they must be ingested through food or supplements. The BCAAs make up 40 percent of the daily requirement of all nine essential amino acids, indicating their importance.
The BCAAs are found in foods containing protein, with the highest concentrations in chicken, beef, salmon, eggs, and whey protein. They can also be supplemented, which can be useful for athletes because free form BCAAs bypass the liver and gut tissue and go directly to the blood stream.
As their name suggests, BCAAs have a branched side chain that simplifies the job of converting each amino acid into energy during intense exertion. They make up about 35 percent of all muscle tissue. The more BCAAs that are present in the muscles, the more they will be used for energy, slowing the breakdown of muscles cells and preventing muscle loss.
Are BCAAs Worth It?
A common question is whether BCAA supplementation is “necessary” or “worth it” for athletes and body builders. Despite the fact that there’s boatloads of research showing BCAAs improve protein synthesis both after resistance training and in the absence of exercise, there’s not much evidence that this actually leads to greater muscle mass gains in the long term.
It appears that total protein intake above a threshold roughly defined as 1.5 g/kg is most important for gaining muscle from resistance exercise. Foods with a high BCAA content, such as whey protein, have been shown to produce greater muscle gains with resistance training.
Based on the evidence, focusing on having a high BCAA and total protein intake will produce the greatest increases in muscle with training. The beauty of BCAA supplements as you’ll see below is they can be easily used during exercise to reduce fatigue, accelerate recovery, reduce muscle soreness, and improve the use of fat for energy.
#1: BCAAs Enhance Muscle Protein Synthesis
BCAAs are well known for triggering protein synthesis. Combining BCAAs with resistance exercise results in maximal protein synthesis because they both trigger something called the mTORC1 signaling pathway that is essential for muscle building.
The BCAAs along with alanine, aspartate, and glutamate are all taken into muscle tissue for energy. It is suggested that muscle is designed to burn BCAAs for energy during exercise, making a large pool essential for performance.
Another great benefit of BCAAs is that if you have to take time off from training due to injury, a need for a break, or lack of time, increasing your BCAA intake will minimize muscle loss. In addition, because BCAAs trigger protein synthesis even in the absence of exercise, the preservation of lean muscle tissue can keep metabolism up and help prevent fat gain when inactive.
For example, in a rodent study, giving BCAAs to rats that had their hind-limbs immobilized for six days helped preserve protein synthesis. The BCAAs didn’t completely prevent muscle atrophy in the rats’ hind limbs, but they helped preserve the muscle to a greater extent than a placebo. The BCAA-fed rats also had lower body fat levels following immobilization.
Take Away: BCAAs Trigger Protein Synthesis for Greater Muscle Growth and the Maintenance of Lean Muscle Mass during Time Off From Exercise.
#2: Leucine-Enriched BCAAs Equalize Muscle Building Between Old & Young
The BCAA leucine can increase protein synthesis by as much as 145 percent when you take it after strength training. It’s become popular lately to take leucine alone without valine and isoleucine, however this is not indicated by the literature.
Research shows that when leucine intake is out of balance with the other BCAAs, it can lead to an imbalance in the blood amino acid levels, reducing the anabolic response. A ratio of about 4 to 1 of leucine to the other two BCAs is most effective for muscle development.
For older people, leucine intake with the other BCAAs is paramount. As you age, creating a muscle-building environment in the body is important, but hard to do. Activation of protein synthesis is impaired, dropping off after age 35. This decreased muscle-building effect along with a tendency to eat less dietary protein with aging are the primary contributors to muscle loss and sarcopenia.
Leucine-enriched BCAAs (a BCAA mixture that is 40 percent leucine) are a “cure” for this because they have been shown to elevate and prolong protein synthesis even in older people in a dose dependent manner after resistance training.
Take Away: A Protein Intake that is Enhanced with Leucine Is Necessary for Older Trainees Who Want to Put On Muscle.
#3: BCAAs Increase Fat Burning and Can Support Fat Loss
Surveys show that people with a higher BCAA intake in their diets have less body fat, more muscle, and better body composition. For example, a large study of 4,429 subjects found that those with higher BCAA intake were the slimmest and had significantly less chance of being overweight compared to those with lower BCAA intake.
Researchers think leucine is the magic bullet for leanness, although only in conjunction with the other BCAAs—a leucine-enriched mixture is best. Isoleucine improves glucose tolerance, while leucine increases energy expenditure and fat oxidation. Greater fat mobilization allows for a more flexible metabolism, which can enable fat loss from a combination of training and diet.
In a review of the role that the essential amino acids play in body composition, scientists wrote that the BCAAs “appear to have unique obesity-reducing effects” because they decrease food intake and body weight by increasing the gene signaling of muscle building pathways.
Take Away: BCAAs Increase Fat Burning and Glucose Tolerance to Keep You Lean. For Fat Loss, Favor Foods with a High BCAA Content.
#4: BCAAs Support Hormone Balance During Intense Training
BCAAs support hormone balance, which plays a role in an athlete’s ability to respond to extreme training loads.
For example, a study that tested the effect of “loading” BCAAs with 6 grams of BCCAs for 3 weeks followed by a week of high-intensity resistance training found that compared to a placebo group, the BCAA group had higher testosterone (T) and lower cortisol (C). In addition to a better T:C ratio, the BCAA group had lower biomarkers of inflammation, indicating that they were responding to the training load effectively.
A second study found that by combining BCAAs, arginine, and carbs, trainees had better hormone balance and a better T:C ratio after an exhaustive exercise test compared to a placebo. Participants who received the BCAA drink recovered much more quickly than those in the placebo trial and had a lower fatigue score at 120 minutes post-workout.
Take Away: BCAAs Improve Hormone Balance for Greater Strength, Power & Endurance Adaptations from Intense Training.
#5: BCAAs May Improve Strength Development With Training
A study of untrained young men taking 4 g/day of leucine gained more strength than a placebo group after 12 weeks of training. The leucine group increased strength by an average of 31 percent more on all exercises compared to the placebo group.
This study hasn’t been replicated with BCAA supplementation; however, protein supplementation has been found to lead to greater strength development in conjunction with strength training.
A recent large-scale analysis of training studies showed that protein supplementation led to greater increases in leg press strength to the tune of an average of 13.5 kg. This review included a variety of protein sources, but all had a high content of BCAAs even though the actual proportions of amino acids varied.
This evidence suggests a diet rich in amino acids from multiple sources including meat, eggs, protein powders, and BCAA supplements for maximizing strength results from training.
Take Away: Boosting Protein Intake Enhances Strength Gains from Training Because The BCAAs Improve Neuromuscular Adaptations.
#6: BCAAs Enhance Endurance Performance and Decrease Fatigue
Reducing fatigue and improving endurance performance is the clinical trial area where BCAAs perform most impressively. There are two mechanisms via which BCAAs improve performance.
First, BCAAs can be burned as energy to maintain ATP energy levels during glycogen-depleting exercise. BCAAs may also enhance the body’s ability to burn fat, increasing the accessible energy pool.
Second, BCAAs prevent central fatigue of the nervous system by inhibiting uptake of tryptophan into the brain. Tryptophan is used to make serotonin in the brain, increasing tiredness and fatigue. Scientists who study the limits of human performance believe that the real limiting factor in performance is when the brain tells you “I’m done.”
For example, participants who took 300 mg/day of BCAAs for 3 days and then completed in an exhaustive exercise trial had 17.2 percent greater resistance to fatigue compared to a placebo, due at least partly to greater fat oxidation in the BCAA trial.
Take Away: Using BCAAs Is an Easy Way to Test Your Endurance Performance Limits by Helping Your Body Burn Fuel More Efficiently.
#7: BCAAs Decrease Muscle Soreness & DOMS for Greater Training Frequency
A series of studies on both trained and untrained individuals show that BCAAs are worth the time and money to reduce (not prevent) DOMS in response to both resistance and endurance exercise.
For example, taking 100 mg/kg of BCAAs reduced muscle soreness at 48 hours and allowed for faster recuperation of strength in untrained women. That BCAAs were effective in an untrained population is noteworthy because DOMS tend to be more severe in untrained muscles.
A second study of trained men found that dosing BCAAs before and after doing 100 muscle-damaging drop jumps reduced muscle soreness significantly. Maximal strength was decreased 33 percent less than a placebo.
The dosing protocol had trainees take BCCAs for 7 days before and for 2 days after training as well as 20 grams before and after the workout for a total of 280 grams. Researchers point to the steady stream of essential amino acids hitting the blood as the reason BCAAs were so effective in this study.
BCAAs are the gem of workout supplements because by preserving the integrity of muscle fibers and reduce post-workout soreness, you can train at a higher intensity more frequently.
Take Away: Using BCAAs to Decrease Soreness and Accelerate Recovery Will Allow You to Train More Frequently So As To Reach Your True Strength and Size Potential.
#8: BCAAs Prevent Muscle Loss During Long-Duration Exercise
In addition to improving endurance performance, BCAAs prevent muscle loss during ultra-endurance exercise. For example, it was found that trained athletes who performed a 24-hour-long exercise trial that included 12 cycles of running, cycling, and kayaking experienced significant muscle protein degradation and had evidence of metabolic stress linked with muscle damage. There was a pronounced drop in plasma levels of BCAAs over the exercise trial, which is linked with muscle loss.
Scientists suggest that providing “simultaneous nutritional support” with BCAAs or a high-BCAA containing protein will prevent catabolism by improving the overall energy-burning pool so that amino acids aren’t released from muscle tissue.
Take Away: Consuming BCAAs is a No-Brainer to Support Performance in Long-Duration Endurance Sports Since They Protect Muscle Tissue.
#9: BCAAs Improve Insulin Health & May Reduce Diabetes Risk
The BCAA isoleucine improves glucose tolerance on its own, and the whole trio of BCAAs can support insulin sensitivity and metabolic rate for improved body composition. For example, a recent study found that the individuals who were in a weight loss trial who lost the most weight had the greatest improvements in insulin sensitivity and the highest BCAA levels.
One thing that should be noted is that diabetics have dysfunctional BCAA metabolism and taking BCAAs elevates insulin, so they should not be used as a treatment for diabetes. Naturally, diabetics should focus on achieving optimal body composition through diet and exercise and work with their doctor to cure diabetes.
Take Away: Non-Diabetics Can Focus on Getting A High Dietary BCAA Intake in Food and Use BCAAS with Training To Support Insulin Health and Reduce Diabetes Risk.
#10: BCAAs Correlate With Longevity and Are Therapeutic
BCAAs are used in medicine to treat liver disease, prevent muscle loss with aging, and reduce mortality risk with cancer. In addition to being therapeutic, BCAAs have an anti-aging effect because they increase the formation of new mitochondria.
In rodent studies, BCAAs have been found to extend lifespan in the same way caloric restriction does, while simultaneously supporting cardiac health.
In a review on BCAAs and human health, scientists write that BCAAs “behave as evolutionary conserved modulators of lifespan,” meaning they will help you live longer if you get enough of them. They also have been found to improve cognition because of the effect they have on the neurotransmitters, improving synthesis of glutamate and GABA and inhibiting serotonin.
Take Away: BCAAs Improve Health and Keep You Young. Tell Your Parents and Grandparents!
Valerio, A., D’antona, G., et al. BCAAs, Mitochondrial Biogenesis, and Healthspan: An Evolutionary Perspective. Aging. May 2011. 3(5), 464-470.
Bajotto, G., Sato, Y., et al. Effect of BCAA Supplementation During Unloading on Regulatory Components of Protein Synthesis in Atrophied Soleus Muscles. European Journal of Applied Physiology. 2011. 111, 1815-1828.
Borgenvik, M., Nordin, M., et al. Alterations in Amino Acid Concentrations in the Plasma and Muscle in Human Subjects during 24 Hour of Simulated Adventure Racing. European Journal of Applied Physiology. 2012. Published Ahead of Print.
Da Luz, Claudia, Nicastro, H., et al. Potential Therapeutic Effects of BCAA Supplementation on Resistance Exercise-Based Muscle Damage in Humans. Journal of the International Society of Sports Nutrition. 2011. 8(23).
Gualano, A, et al. Branched-Chain Amino Acids Supplementation Enhances Exercise Capacity and Lipid Oxidation During Endurance Exercise After Muscle Glycogen Depletion. Journal of Sports Medicine and Physical Fitness. 2011.51(5), 82-88.
Hsu, M., Chien, K., et al. Effects of BCAA, Arginine, and Carbohydrate Combined Drink on Post-Exercise Biochemical Response and Psychological Condition. Chinese Journal of Physiology. April 2011. 542), 71-78.
Glynn, E., Fry, C., Drummond, M., Timmerman, K., Dhanani, S., Volpi, E., Rasmussen, B. Excess Leucine Intake Enhances Muscle Anabolic Signaling but Not Net Protein Anabolism in Young Men and Women. The Journal of Nutrition. 2010. 140(11), 1970-1976.
Sharp, C., Pearson, D. Amino Acid Supplements and Recovery from High-Intensity Resistance Training. Journal of Strength and Conditioning Research. 2010. 24(4), 1125-1130.
Ipoglou, T., King, R., Polman, R., Zanker, C. Daily L-Leucine Supplementation in Novice Trainees During a 12-Week Weight Training Program. International Journal of Sports Physiology and Performance. 2011. 6(1), 38-80.
Jourdan, C., et al. Body Fat Free Mass is Associated with the Serum Metabolite Profile in A Population Based Study. PLOS One. 2012. 7(6), e40009.
Lustgarten, M., et al. Serum Predictors of Percent Lean Mass in Young Adults. Journal of Strength and Conditioning Research. 2013. Published Ahead of Print.
Peltier, S., Vincent, L., et al. Effects of Carbohydrates-BCAAs-Caffeine Ingestion on Performance and Neuromuscular Function During a 2-H Treadmill Run. Journal of the International Society of Sports Nutrition. December 2011. 8(22).
Rondanelli, M., Opizzi, A., Antoniello, N., Boschi, F., Iadarola, P., Pasini, E. Effect of Essential Amino Acid Supplementation on Quality of Life, Amino Acid Profile and Strength in Institutionalized Elderly Patients. Clinical Nutrition. 2011. 30(3).
Plauth, M., Schutz, T. BCAAs in Liver Disease: New Aspects of Long Known Phenomena. Current Opinions in Clinical Nutrition and Metabolic Care. January 2011. 14(1), 61-66.
Shah, S., Crosslin, D., et al. BCAA Levels are Associated with Improvement in Insulin Resistance with Weight Loss. Diabetologia. February 2012. 55(2), 321-330.
Hayaishi, S., Chung, H., et al. Oral BCAA Granules Reduce the Incidence of Hepatocellular Carcinoma and Improve Event-Free Survival in Patients with Liver Cirrhosis. Digestive Diseases. 2011. 29(3), 326-332.
Cole, J., Mitala, C., et al. Dietary BCAAs Ameliorate Injury-Induced Cognitive Impairment. Proceedings of the National Academy of the Sciences. January 2010. 107(1), 366-371.
Thomson, J., Ali, A., Rowlands, D. Leucine-Protein Supplemented Recovery Feeding Enhances Subsequent Cycling Performance in Well-Trained Male Cyclists. Applied Physiology, Nutrition, and Metabolism. 2011. 36(2), 242-253.
Walker, D., Dickinson, J., et al. Exercise, Amino Acids, and Aging in the Control of Human Muscle Protein Synthesis. Medicine and Science in Sports and Exercise. May 2011. Published Ahead of Print.
Qin, L., Xun, P., Bujnowski, D., Daviglus, M., Van Horn, L., Stamler, J., He, K. Higher Branched-Chain amino Acid Intake is Associated with a Lower Prevalence of Being Overweight or Obese in Middle-Aged East Asian and Western Adults. The Journal of Nutrition. 2010. 141(2), 249-254.
Ra, S., et al. Additional Effects of Taurine on the Benefits of BCAA Intake for the Delayed-Onset Muscle Soreness and Muscle Damage Induced by High-Intensity Eccentric Exercise. Advances in Experimental Medicine and Biology. 2013. 776, 179-187.
Jackman, S., et al. Branched-Chain Amino Acid Ingestion Can Ameliorate Soreness From Eccentric Exercise. Medicine and Science in Sports and Exercise. 2010. 42(5), 962-970.
Shimomura, Y., et al. Branched-Chain amino acid Supplementation Before Squat Exercise and Delayed-Onset Muscle Soreness. International Journal of Sport Nutrition and Exercise Metabolism. 2010. 20(3), 236-244.