Branched-Chain Amino Acids

Branched-chain amino acids (BCAAs) are named for their structure and include leucine, isoleucine, and valine. They are essential nutrients and are important to athletes because they stimulate the building of protein in muscle. [10]

Benefits of BCAAs

Improved recovery in days following exercise

A 2010 study found that consumption of 100mg of BCAAs per kg of body weight in the morning before exercise (7 sets of 20 squats) resulted in significantly lowered delayed onset muscle soreness (DOMS) during the two days following exercise. Furthermore, when tested 2 days after exercise, the group who consumed BCAAs experienced less loss of strength during recovery than the placebo group, suggesting that supplementation with BCAAs may suppress muscle damage during exercise. [4]

Improved performance in days following exercise

A 2011 study compared consumption of 300mg of BCAA per kg of body weight per day versus a placebo over a 3 day period, where participants were subject to a glycogen depleting workout on day 2 followed by exhaustive exercise on day 3. Those who had supplemented with BCAAs had 17.2% greater resistance to fatigue, reduced respiratory exchange ratio, and higher plasma glucose levels due to enhanced lipid oxidation during the exhaustive exercise. [6]

Maintain muscle mass while losing weight

A 2016 study focused on athletes who consumed a 14 gram supplement containing 7 grams of BCAAs both before and after exercise and athletes who consumed an isocaloric (having similar caloric values) 14 gram carbohydrate supplement before and after exercise. Members of both groups were subject to a hypocaloric diet over the 8 week study period. While both groups lost fat mass, the group who supplemented with BCAAs maintained muscle mass and the non-BCAA group lost muscle mass. Furthermore, the BCAA group saw greater increases in their one rep max (1RM) on squats, and the BCAA group saw increases to their 1RM for bench press while the non-BCAA group saw decreases. [1]

Improved reaction time during activity

In a study from 2011, it was found that supplementing with 7 grams of BCAAs one hour before exercise simulating a soccer game reduced multiple choice reaction times by 10%. [5]

 

Improved lactate threshold

In a 2009 study, participants were given either 6 grams of BCAAs per day or a placebo for 6 days, and then performed an incremental loading exercise test on day 7. Those in the BCAA group had a higher output by approximately 6% and had an approximately 4% higher VO2max. [9]

 

Not Useful for

Improving performance during endurance activity

While BCAAs are beneficial in improving recovery and reducing soreness in the days following athletic activity, several studies using various supplementation methods have shown that they do not aid in reducing muscle damage, improving performance / strength, or improving renal function during endurance running and aerobic exercise [2], [3], [8]. One study has shown that consumption of a 200 calorie serving of BCAAs both prior to 60 minutes into exercise lowered the participants perceived levels of exertion over consumption of a non-caloric placebo [7]. However, BCAA supplementation still aids in post exercise recovery [8].

Conclusions

• BCAAs provide great benefits in the days following exercise by aiding the recovery process.
• BCAAs also help to maintain muscle mass in individuals consuming a hypocaloric diet in an effort to lose weight.
• BCAA supplementation before activity can help with decision making as well as increased output at lactate threshold and VO2max levels of exertion.
• BCAAs do not aid performance in long endurance types of activity.

 

References

[1] https://www.ncbi.nlm.nih.gov/pubmed/26733764

[2] https://www.ncbi.nlm.nih.gov/pubmed/24477835

[3] https://www.ncbi.nlm.nih.gov/pubmed/23007065

[4] https://www.ncbi.nlm.nih.gov/pubmed/20601741

[5] https://www.ncbi.nlm.nih.gov/pubmed/22050133

[6] https://www.ncbi.nlm.nih.gov/pubmed/21297567

[7] https://www.ncbi.nlm.nih.gov/pubmed/20386134

[8] https://www.ncbi.nlm.nih.gov/pubmed/20087302

[9] https://www.ncbi.nlm.nih.gov/pubmed/19352063

[10] http://www.webmd.com/vitamins-supplements/ingredientmono-1005-branched-chain%20amino%20acids.aspx?activeingredientid=1005