Why supplement with BCAA's?

I read up a little bit about supplementation of BCAA's and it makes sense why they could be useful to use before, during, and after their workouts. But I also read up a little bit about proteins and their amino acid profiles and it shows that most proteins already have the BCAA's in them and enough of it. So for that reason I don't understand why one would need to further supplement with BCAA's if there are already consuming enough protein around their workout times. The best example I can think of is for me for example, I like to have protein shakes before and after my workouts.

Is there any reason why one would need to have more BCAA's during those times if they were already getting enough from the protein? Or does the idea of supplementing with BCAA's already assume that you aren't getting enough around those times?

DrSquat's picture

The role of BCAA's in

The role of BCAA's in exercise

The branched-chain amino acids (i.e. leucine, isoleucine and valine) constitute approximately one-third of skeletal muscle protein [53]. An increasing amount of literature suggests that of the three BCAAs, leucine appears to play the most significant role in stimulating protein synthesis [54]. In this regard, amino acid supplementation (particularly the BCAAs) may be advantageous for the exercising individual.
A few studies reported that when BCAAs were infused in humans at rest, protein balance increases by either decreasing the rate of protein breakdown, increasing the rate of protein synthesis or a combination of both [55,56]. Following resistance exercise in males it has been shown that the addition of free leucine combined with carbohydrate and protein led to a greater increase protein synthesis as compared to taking the same amount of carbohydrate and protein without leucine [57]. However, the majority of the research relative to leucine ingestion and protein synthesis has been conducted using animal models. Similar research needs to be conducted in healthy individuals engaging in resistance exercise.
BCAA ingestion has been shown to be beneficial during aerobic exercise. When BCAAs are taken during aerobic exercise the net rate of protein degradation has been shown to decrease [58]. Equally important, BCAA administration given before and during exhaustive aerobic exercise to individuals with reduced muscle glycogen stores may also delay muscle glycogen depletion [59]. When BCAAs were given to runners during a marathon it improved the performance of "slower" runners (those who completed the race in 3.05 h-3.30 h) as compared to "faster" runners (those who completed the race in less than 3.05 h) [60]. Although there are numerous reported metabolic causes of fatigue such as glycogen depletion, proton accumulation, decreases in phosphocreatine levels, hypoglycemia, and increased free tryptophan/BCAA ratio, it is the increase in the free tryptophan/BCAA ratio that may be attenuated with BCAA supplementation. During prolonged aerobic exercise, the concentration of free tryptophan increases and the uptake of tryptophan into the brain increases. When this occurs, 5-hydroxytryptamine (a.k.a. serotonin), which is thought to play a role in the subjective feelings of fatigue, is produced. Similarly, BCAAs are transported into the brain by the same carrier system as tryptophan and thus "compete" with tryptophan to be transported into the brain. Therefore, it is believed that when certain amino acids such as BCAAs are present in the plasma in sufficient amounts, it theoretically may decrease the uptake of tryptophan in the brain and ultimately decrease the feelings of fatigue [61,62].
Furthermore, there is also research to suggest that BCAA administration taken during prolonged endurance events may help with mental performance in addition to the aforementioned performance benefits [60]. However, not all research investigating BCAA supplementation has reported improvements in exercise performance. One such study [63] reported that leucine ingestion taken before and during anaerobic running to exhaustion (200 mg/kg of body weight) and during a strength training session (100 mg/kg of body weight) did not improve exercise performance. Reasons for discrepant results are not clear at this time, but at the very minimum, it seems apparent that supplementation with BCAAs does not impair performance.
Because BCAAs have been shown to aid in recovery processes from exercise such as stimulating protein synthesis, aiding in glycogen resynthesis, as well as delaying the onset of fatigue and helping maintain mental function in aerobic-based exercise, we suggest consuming BCAAs (in addition to carbohydrates) before, during, and following an exercise bout. It has been suggested that the RDA for leucine alone should be 45 mg/kg/day for sedentary individuals, and even higher for active individuals [53]. However, while more research is indicated, because BCAAs occur in nature (i.e. animal protein) in a 2:1:1 ratio (leucine: isoleucine: valine), one may consider ingesting ≥ 45 mg/kg/day of leucine along with approximately ≥ 22.5 mg/kg/day of both isoleucine and valine in a 24 hour time frame in order to optimize overall training adaptations. This will ensure the 2:1:1 ratio that appears often in animal protein [64]. It should not be overlooked that complete proteins in whole foods, as well as most quality protein powders, contain approximately 25% BCAAs. Any deficiency in BCAA intake from whole foods can easily be remedied by consuming whey protein during the time frame encompassing the exercise session; however, an attempt should be made to obtain all recommended BCAAs from whole food protein sources.

wlewisj's picture

Charles, I think you are


I think you are fine if your protein is high in BCAA's. I do not like to take protein shakes before or during workouts so I take 5-10 grams of BCAA's during my workout.

Willis Lewis, Jr.
"The man that dreams success is already successful"