What are BCAAs, and what are they used for?

Question

BCAAs seem to be a widely recommended (for example, Art DeVany and Martin Beckham of LeanGains) weightlifting supplement. What are they, and how can they help a training program?

Answer 1

BCAA stands for branched-chain amino acids. According to this article, from the Journal of Nutrition:

BCAAs (leucine, isoleucine, and valine), particularly leucine, have anabolic effects on protein metabolism by increasing the rate of protein synthesis and decreasing the rate of protein degradation in resting human muscle. Also, during recovery from endurance exercise, BCAAs were found to have anabolic effects in human muscle.

That is, BCAA's may stimulate muscle growth. According to this article, timing is important: Leucine can stimulate muscle protein synthesis for a short period, but with chronic supplementation, the body quickly adapts, and muscle protein synthesis returns to normal after 2 hours.

This well-cited blog post summarizing the latest research on BCAA's reports that BCAA supplementation has been shown to decrease muscle fatigue and soreness during running, as well as increasing the oxygen carrying capacity of the blood and decreasing muscle damage during athletic training. However, the author cites a study that reports that supplementing with casein and whey protein works better for resistance training than supplementing with BCAA's.

It is worth noting that you don't have to get BCAA's from supplements, they occur naturally in protein-containing foods. In fact, amino acid supplementation has some major disadvantages:

Ingesting free, crystalline L-amino acids is thought by many athletes to be superior to ingesting natural foods containing protein for muscle protein synthesis. However, amino acids using the same carrier system compete with each other for absorption. Thus, ingesting one amino acid or a particular group of amino acids that use the same carrier system may create, depending on the amount ingested, a competition between the amino acids for absoprtion. The result may be that the amino acid present in highest conentration is absorbed but also may impair the absorption of the other, less concentrated amino acids carried by that same system. Thus, amino acid supplements may result in impaired or imbalanced amino acid absorption. Furthermore, absorption of peptides (which are obtained from digestion of natural protein-contain foods) is more rapid than absorption of an equivalent mixture of free amino acids ... Moreover, the supplements are usually expensive, typically taste terrible, and > may cause gastrointestinal distress.

(Advanced Nutrition and Human Metabolism)

Answer 2

Following on from the excellent answer given above, I'll try to flesh out my current understanding on BCAAs:

BCAAs are among the nine essential amino acids for humans, accounting for 35% of the essential amino acids in muscle proteins and 40% of the preformed amino acids required by mammals. BCAAs are among the proteinogenic amino acids, of which there are three:

1. leucine,
2. isoleucine, and
3. valine

The journal article below provides a nice overview of BCAAs

As stated above BCAAs stimulate muscle growth in particular I’ve highlighted leucine as being particularly important as it is responsible for most of the anabolic effects of a meal and current research suggests that 3g (~0.05g/kg bodyweight) of leucine is required to muscle protein synthesis. However, the body quickly adapts and you need to consume multiple meals per day containing 3g (or supplement) to induce this (refer to the journal article: Optimal Protein Intake). Interestingly, in this study leucine helped to burn fat during periods of food restriction, such as climbing at high altitudes, while keeping their muscle tissue intact.

Should you supplement?

You don't have to get BCAA's from supplements, they occur naturally in protein-containing foods:

However, I find supplementation to be convenient and the best solution for me.

How much to take?

I aim for around 0.05g/kg bodyweight of leucine for muscle protein synthesis a few times during the day. But factoring in the data from the Tipton and Wolfe study below, use the following as a guide:

• Inactive Adult -.6 – .8g x bw
• Strength Athlete – 1.0 -1.2g x bw
• Endurance Athlete – .8 – 1.0g x bw
• Bodybuilder – 1.2-1.4g x bw

Protein and Amino Acids for Athletes

How I take them

For me the best way to use BCAAs is both pre and post workout to keep muscle mass, especially on a calorie restricted or low-carb diet. I take 10g of BCAA (I add a dash of extra leucine) with either green tea or coffee on and empty stomach before my morning workout (if I recall correctly, Arthur De Vany in The New Evolution Diet suggests taking 15g). Immediately after my workout I then take a slug of protein, i.e. 25 grams (as recommended by this study to build muscle) and then I take some more BCAAs couple of hours after that again.

If you really want to wake-up before your morning workout you could try Robb Wolf's suggestion of 400-600mg acetyl l-carnitine and 200-400mg alpha lipoic acid together on an empty stomach. Zing!

So, in summary, for me taking BCAAs as I’ve descibed above seems to:

• reduce the overall hunger/carb-cravings (likely due to gluconeogenesis)
• provide a little more energy for the workout
• results in less DOMS (soreness)