The thought that BCAA’s were uniquely key to muscle protein synthesis has been ongoing for upwards of three decades. This paper in the Journal of the International Society of Sports Nutrition set the record straight. There are 11 non-essential amino acids (NEAAs) and 9 essential amino acids (EAAs). EAAs cannot be adequately produced into the body, and therefore must ingested via diet or supplementation. Of the 9 EAAs, leucine, isoleucine, and valine are make up the branched-chain group.
- “Muscle protein is in a constant state of turnover, meaning that new protein is continuously being produced while older proteins are being degraded. The anabolic state has no specific definition, but generally refers to the circumstance in which the rate of muscle protein synthesis exceeds the rate of muscle protein breakdown. The results in a gain of muscle mass. Conventionally the anabolic state is considered to be driven by a stimulation of muscle protein synthesis, but theoretically could also result from an inhibition of muscle protein breakdown.”
- “Expressed differently, it is impossible for muscle protein synthesis to exceed the rate of muscle protein breakdown when the precursors are derived entirely from protein breakdown, and thus an anabolic state cannot occur in the absence of exogenous amino acid intake.”
- After we consume a protein source and catabolize this into amino acids for absorption, it can go in one of the following directions: enter into plasma, become oxidized by a certain tissue, or (hopefully) stimulate muscle growth.
- To stimulate muscle growth/protein, we need all 9 EAAs. “If only 3 EAAs are consumed, as is the case with consumption of BCAAs, then protein breakdown is the only source of the remaining EAAs required as precursors for muscle protein synthesis. It is therefore theoretically impossible for consumption of only BCAAs to create an anabolic state in which muscle protein synthesis exceeds muscle protein breakdown.”
- Two studies used intravenous supplementation of BCAA’s on humans; intravenous and oral supplementation have showed similar absorption in previous studies. “We can conclude from these two studies that BCAA infusion not only fails to increase the rate of muscle protein synthesis in human subjects, but actually reduces the rate of muscle protein synthesis and the rate of muscle protein turnover.…Instead, since muscle protein breakdown decreased, the availability of EAAs also fell, which in turn actually reduced the rate of muscle protein synthesis.”
- “When all evidence and theory is considered together, it is reasonable to conclude that there is no credible evidence that ingestion of a dietary supplement of BCAAs alone results in a physiologically-significant stimulation of muscle protein. In fact, available evidence indicates that BCAAs actually decrease muscle protein synthesis. All EAAs must be available in abundance for increased anabolic signaling to translate to accelerated muscle protein synthesis.”
- An intact protein, such as whey, generally contains all EAAs. Whey in combination with BCAAs may enhance the anabolic effects of they whey itself. “For example, the addition of 5 g of BCAAs to a beverage containing 6.25 g whey protein increased muscle protein synthesis to a level comparable to that induced by 25 g of whey protein.”
- It seems reasonable to correlate higher value to leucine over isoleucine and valine due to the mechanism of protein synthesis. Despite this, there are numerous limitations to supplementing leucine alone such as “…elevation of the plasma concentration of leucine activates the metabolic pathway that oxidizes all of the BCAAs. As a result, ingestion of leucine alone results in a decrease in the plasma concentrations of both valine and isoleucine.”
Let’s wrap it up then and simply say that we need ALL EAAs for muscle protein synthesis- diet is superior to supplementation. “We conclude that dietary BCAA supplements alone do not promote muscle anabolism.” BCAA’s are most likely not worth considering but may be beneficial if fortified within a whey supplement.
Have you ever heard anyone attribute their osteoarthritic knees to running? I’m referring to sub-elite populations- which is 99.9% of runners. Below is a slide I used in class highlighting a nice systematic review published here in 2017. Running is most often correlated to lower incidences of knee OA. “These results indicated that a more sedentary lifestyle or long exposure to high-volume and/or high-intensity running are both associated with hip and/or knee OA.”
What do Bill Gates, Warren Buffet, and Opera Winfrey have in common? Aside from being incredibly successful and influential, they abide by the 5-hour rule. “Many of these leaders, despite being extremely busy, have set aside at least an hour a day (or five hours a week) over their entire career for activities that could be classified as deliberate practice or learning.” This brief article on Inc.com breaks down the five-hour rule into three distinct sectors to maximize each hour/day of deliberate learning.
- Read. The importance of reading is immeasurable. To take this a step further, we shouldn’t limit this to just reading. Let’s say absorbing information can be done by reading books, articles, blogs, etc.; watching presentations, TED Talks, documentaries, so on..; or listening to audio-books, podcasts, and/or lectures.
- Reflect. Executives will often take the time to schedule “think sessions”. “AOL CEO Tim Armstrong makes his senior team spend four hours per week just thinking.” This allows for not only a boost in creativity, but also a scheduled time to discuss/share topics recently absorbed, improving comprehension and retention.
- Experiment. This is an opportunity to implement a concept or observe it in practice. “Google famously allowed employees to experiment with new projects during 20 percent of their work time.”
“Just as we have minimum recommended dosages of vitamins and steps per day and of aerobic exercise for leading a healthy life physically, we should be more rigorous about how we as an information society think about the minimum doses of deliberate learning for leading a healthy life economically.”
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