Just How Essential Are Amino Acids?

I’m sure you’ve all heard of amino acids. They’re a buzz word in the fitness industry often associated with supplementation. Now, everyone might have a vague awareness of amino acids, but do you really know what they are?

If you’re like the majority of the population, your answer will be ‘no’. Let’s get you up to speed. Throughout this article, we’re going to discuss what amino acids are, what they do, and how we can use them to enhance our fitness goals.  

What Exactly Are Amino Acids?  

So, what exactly are amino acids (AA)? AA are essentially the building blocks that form a protein. Therefore, they are an essential component of the human body. Protein is needed for many physiological functions including nutrient absorption, tissue repair, and protein synthesis (the muscle building process!), the main association of protein consumption.

There are a total of 20 different AA, they all follow the same molecular structure, but have a unique R-group. What is an R-group? Well, this is starting to get very technical but, in short, an R-group is a side-chain that is defined by its various properties such as shape, charge and size. The different R-groups change how the AA interact with other AA in the protein chain. We need a range of AA so we can create the correct protein chain for the specific function we want that protein to perform.  

Our body can produce 9 of the 20 AA, these are known as non-essential amino acids (NEAA) because we create them within our bodies. The other 11 AA are known as, unsurprisingly, essential amino acids (EAA) because we need to consume them but cannot be produced naturally and so we need to find alternative sources for them, such as through diet and supplementation.

When we consume AA around 30% of AA is passed into our circulation, the rest is taken up by our liver. Therefore, we might not be using as much as we think.  

Branched-Chain Amino Acids 

Within EAA we have a further subsection: branched-chain amino acids (BCAAs). There are 3 BCAAs; valine, leucine, and isoleucine.

BCAAs are building blocks of protein, and are involved in the signalling of muscle protein synthesis (MPS). MPS is essentially switched on by the mammalian target of rapamycin (mTOR) molecular signaling pathway.

BCAAs, specifically leucine, has been shown to activate the mTOR signalling pathway. Therefore, scientists believe the consumption of additional BCAAs will result in greater, more frequent stimulation of the mTOR pathway. In turn, this suggests an increase in skeletal muscle growth. Perfect for us gym-goers!  

So, what is so special about leucine in particular? Well, as stated above, scientists believe leucine is independently responsible for switching on MPS. Once switched on, MPS is then activated for approximately two hours.

However, as nice as this all sounds, recent research suggests it is a little bit more complicated than just ‘switching on’ MPS.
Although the hypothesis is valid, several other factors must be considered when looking to build skeletal muscle mass.

While leucine does stimulate MPS, we still need the other essential amino acids to rebuild the new muscle. Just because it is stimulated, does not mean the muscle can be built.

Imagine, for example, you want to build a wall. You have all the tools and knowledge to do so, but you don’t have any bricks. Seeing as bricks are a fundamental component in building a wall it is impossible to create that wall, no matter how much desire or stimulation you have. 

The amino acids are your body’s bricks!

Let’s consider a recent study by Jackman et al. (2017): Ingesting BCAAs alone increased MPS, but ingesting whey protein containing all 11 EAA increased MPS twice as much as BCAAs alone.

Going back to our ‘building a wall’ analogy, there is enough stimulation in BCAAs to think and prepare to build the wall (or in our case, stimulate muscle growth), but there isn’t anything to actually build the wall with.

The same concept occurs on the reverse: when we lack BCAAs in the presence of the other EAAs, we lack the stimulation to build the muscle. I.e. we have all the bricks, but lack the workers or stimulation to build the wall.

This situation is commonly seen among vegan athletes. Research has shown vegan and animal sources of protein differ in digestibility and AA composition. AA from animal sources tend to contain more EAA compared to plant sources, therefore athletes following a vegan diet are recommended to consume a variety of protein sources, and consider protein supplementation. Therefore, instead of thinking we need to consume BCAAs, we should think along the lines of needing to consume all the EAA. 

For more on vegan-specific amino acid discussion, see How To Build Muscle On a Vegan Diet.

Amino acid-based research has not focused solely on muscle-building properties: they have also proposed other ergogenic benefits. In addition to muscle-building qualities, the European Food Safety Authority also claims BCAAs:

• decreases muscle soreness
• promotes muscle fatigue recovery post-exercise
• helps support a healthy immune system
• improves cognitive function following exercise

Unfortunately, research surrounding BCAAs as an ergogenic aide focuses on skeletal muscle repair and growth. Therefore, studies surrounding other claims for BCAA supplementation remain limited and inconclusive. The second most researched claim of BCAAs is their ability to reduce muscle soreness following exercise. In a study by Jackman et al. (2010), BCAA supplementation was linked to a slight decline in muscle soreness following exercise. However, other studies have shown no effect, making it difficult to determine whether BCAAs can reduce muscle soreness following exercise.

As a result, there is still much more research that needs to be done.  

Should You Take BCAA Supplements?

As we’ve discussed, BCAAs are important on a day to day basis, but they are already found in abundance in most animal products, therefore those on a reasonably balanced diet would not require BCAA supplementation and wouldn’t likely see any noticeable benefit.

As we’ve discussed, research remains limited, inconclusive and conflicting, therefore taking BCAA supplements may or may not be beneficial to you: trying BCAA supplements can’t do any harm to your body (though the same can’t be said for your wallet!). Again, those consuming a vegan diet are more likely to see benefits from BCAA supplements, may work for you. If you do choose to take BCAA supplementation the standard dose of isoleucine is 48-72mg/kg. The standard leucine dose is 2-10mg/kg, and a combination dose of all 3 BCAAs is 20g, with a balanced ratio of leucine and isoleucine.  

Conclusion 

So, should we care about AA? Yes, absolutely, they are the building blocks to our muscles and are needed to stimulate and create muscle mass growth and maintenance. BCAAs have been shown to stimulate muscle growth, but we also need the other AA to build the muscle. Since BCAA research is still in its early days, the best recommendation we can give for now is to eat a diet high in good-quality protein, containing all the AA. If you’re following a plant-based diet, or not sure if you’re intaking enough BCAAs, consider taking supplementation, but at present, we are not certain it has any benefit over AA packed foods such as whey, eggs, beef, and cod, etc. when consumed in sufficient quantities. If you are going to take a supplement, choose whey protein, it will typically contain all the necessary AA within the formula.  

Summary

• Amino acids are the building blocks of protein. 
• We need to consume 9 essential amino acids through our diet. 
• BCAAs are 3 amino acids that play a role in stimulating muscle building, specifically the amino acid leucine. 
• All amino acids are required to physically build the muscle, we can’t rely on stimulation alone. 
• All 9 essential amino acids are typically found in animal products. 
• Vegan athletes and those lacking protein might benefit from BCAA supplementation. 
• BCAAs might also aid muscle recovery, the immune system, and cognitive function, but research is limited and claims remain inconclusive. 
• If you’re looking to build or maintain muscle mass your focus should be on total daily protein quantity. 
• BCAAs could be useful, even for just a placebo effect, there is no harm associated with taking BCAA supplementation for a potential benefit.