Branched-chain amino acids (BCAAs) are three of the nine essential amino acids needed for survival. They include leucine, isoleucine and valine.
Since your body doesn't produce BCAAs, you must get them through food or supplements. Most people consume enough BCAAs when they eat a balanced diet.
Claims that BCAAs can improve muscle mass and exercise performance have made them popular among athletes and people looking for ways to improve fitness. Although BCAA supplements are safe for most people, they should be taken with caution.
This article explains how BCAAs affect your body, how you can increase them, and how they can help. It also includes side effects, warnings, and pros and cons of adding to normal BCAA levels.
BCAA effects on the body
Amino acids are the "building blocks" of proteins, which are necessary for the growth of healthy muscles, skin, hair, blood, bones and more. Amino acids also influence metabolism.
Branched chain amino acids are so called because of their chemical structure. Unlike other amino acids, which are broken down in the liver, BCCAs are broken down in muscle tissue.
BCAAs stimulate protein synthesis and, as a result, stimulate an anabolic response (the process by which your muscles repair and grow in response to the stress of exercise).
Branched-chain amino acids are also more easily converted into glucose during exercise than other types of amino acids. Your body uses glucose for energy.
These responses can help improve exercise performance, build muscle mass, and improve exercise recovery.
Essential vs. non-essential amino acids
You can increase BCAA intake by following a high-protein diet. BCAA foods include the following:
- Beef
- Poultry
- Salmon, tuna and other fish
- Eggs
- Dairy products such as milk, cheese and yogurt
- Nuts and seeds
- peanut butter
- Quinoa
- Soy products such as tofu and tempeh
- Legumes, including beans, lentils and peas
Powder and supplements
BCAA powder and oral supplements are available as over-the-counter products. Formulations vary by manufacturer and specific product. A typical formulation is leucine, isoleucine and valine in a ratio of 2:1:1. There is no set value for the intake of BCAAs.
BCAA supplements are most commonly consumed by athletes and others who participate in regular, moderate physical activities at various exercise levels. They are generally safe for most healthy individuals to take daily. For optimal benefits, taking BCAAs before or after your workout is advised.
6 Benefits of Consuming More BCAA
Six benefits of BCAAs are:
Reduction of muscle pain
Research shows that BCAAs can reduce delayed onset muscle soreness (DOMS), the muscle soreness that occurs between 12 and 24 hours after exercise. Supplementing with BCAAs before exercise can reduce muscle soreness after exercise and speed up recovery time.
In a systematic review, researchers reported that muscle damage was limited with daily BCAA supplementation of more than 200 milligrams per kilogram of body weight (mg/kg) for longer than 10 days and at least seven days before performing the damaging exercise.
Stimulating muscle growth
Researchers reported evidence that BCAAs, when used after strength training, stimulated 22% greater muscle protein synthesis (the process involved in making muscle) than placebo (an ineffective substance given to people in a control group). The findings were based on the results of participants who consumed a drink of BCAAs after their strength training.
Improving endurance
Taking BCAA supplements can improve exercise endurance and reduce exercise fatigue.
In one study, participants who took BCAA supplements before exercise had lower serotonin blood levels than those who took a placebo. Serotonin contributes to central fatigue. Central fatigue is the mental fatigue that occurs during prolonged aerobic exercise. Those taking BCAAs also had improved energy metabolism.
Maintenance of muscle mass
BCAAs can help people maintain muscle mass, which can be depleted as body proteins are lost in certain diseases such as cancer. Research suggests that a high-protein diet that contains extra BCAAs, especially leucine, can help maintain muscle mass under these conditions.
Counteracting the effects of advanced liver cirrhosis
BCAA supplements are valuable as a nutritional intervention for preventing complications of liver diseases. They have been shown to improve quality of life and prognosis in people with liver disease cirrhosisan advanced stage of liver disease.
Separate studies have also shown that BCAA supplementation can improve liver signs and symptoms encephalopathy (the loss of brain function that occurs with advanced liver disease), weakness and fatigue, and sleep disorders.
Regulating blood sugar levels
Research shows that BCAAs may play multiple roles in insulin resistance (the inability of cells to absorb blood sugar) by regulating blood sugar levels and encouraging cells to accept more sugar from your blood.
Side effects of consuming too much BCAA
Many people consume large amounts of amino acids as dietary supplements without side effects. However, the side effects of consuming too much BCAA can vary depending on your age, health status, diet and medications.
Although there are inconsistencies regarding the presence of side effects from too much BCAA, the most common reactions are the following:
These effects appear temporary when they occur and are often limited to the initial period of administration.
Other possible side effects of BCAA supplementation may include the following:
- Possible risk of cancer: BCAAs may provide essential nutrients for cancer growth and an energy source for tumors, suggesting a link between BCAA metabolism and cancer that requires further research.
- Barrier to Weight Loss: Research suggests that lowering BCAA consumption can improve metabolic health, even if total calories are not reduced.
- Liver damage: Research shows that BCAA supplements can cause liver damage if consumed in combination with a high-fat diet.
- Heart disease: There is some evidence that high levels of BCAAs may be a marker for cardiovascular disease, although further research is needed.
Special Precautions: Who Should Avoid BCAAs?
Due to a lack of research, little is known about the potential adverse effects and interactions of BCAAs with other chemicals. If you have a chronic condition and/or take medications on a daily basis, consult your healthcare provider before taking BCAA supplements.
There are no known interactions between BCAAs and other supplements, foods or compounds. No studies have found definitive interactions between BCAAs and specific medications, but that doesn't mean those interactions don't exist.
There is insufficient research into the safety of using BCAA and other amino acid supplements for the following groups:
- Children
- Older adults
- Pregnant or breastfeeding women
- People with liver disease
- People with diabetes
- People with other chronic conditions
People with maple syrup urine disease (MSUD), a rare congenital condition, should not take BCAAs. This disease disrupts the proper breakdown of BCAAs. Consuming too many BCAAs can lead to a buildup of toxic BCAA products linked to nerve and brain symptoms.
Although more research is needed, people with amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) or at high risk for the disease should avoid BCAAs. Higher levels of BCAAs have been observed in people with ALS, although a pooled analysis of five cohort studies did not find any link between BCAAs and ALS risk.
In one study, supplementing with 60 grams (g) of BCAA changed blood levels of tryptophan, phenylalanine, and tyrosine, which could cause depression in susceptible people. People with a history of depression should consult their healthcare provider before taking BCAA supplements.
Pros and cons of BCAA supplements
Whether BCAA supplements are right for you depends on your goals and overall fitness. Your healthcare provider can help you decide if you may benefit from BCAA supplements.
Consider the following pros and cons of adding BCAA supplements to your routine.
Benefits of Taking BCAA Supplements:
- Although research is inconclusive, BCAA supplements may benefit athletes and others interested in improving physical performance, increasing muscle mass and reducing exercise-related muscle damage.
- If your goal is to increase BCAA blood plasma levels to achieve training-related goals, BCAA supplements allow you to do this in controlled amounts rather than getting it from whole foods.
- BCAA supplements may be suitable for people who are fasting but want to consume enough protein to build muscle.
Cons of taking BCAA supplements:
- Eating a balanced, high-protein diet usually provides adequate BCAA levels without the need for supplements. Whole food sources of BCAA can provide better results than supplements because whole foods also contain other essential amino acids and nutrients that work together naturally in your body.
- While there is some evidence that consuming 'isolated' BCAAs can reduce muscle soreness, it is important to note that BCAAs are often combined in formulations containing products such as whey protein or carbohydrates. These factors can influence the effect of BCAA supplements.
- Depending on your medical condition, health risks, and other factors, consuming BCAA supplements may increase your risk for certain health problems.
BCAAs include leucine, isoleucine and valine. Although your body needs these three amino acids for normal functioning, it cannot produce them. You must consume them through food or supplements.
Some research suggests that BCAAs may promote muscle growth, prevent muscle loss and reduce muscle soreness after exercise. There is also some evidence that they may improve the signs and symptoms of people with advanced liver disease.
Although high levels of BCAAs are safe for most people, they can increase the risk of certain health problems. Consult your doctor before adding BCAA supplements to your diet.
