Essential Amino Acids (EAAs) Explained
Everybody has heard of protein before, but not as many people are familiar with its more granular details: amino acids.
The essential amino acids are not just a long-standing popular supplement, but an important concept to know to ensure your daily protein intake is sufficient.
So, the aim of this article is to break down the research relevant to you to help you better understand them.
If you have any questions left unanswered, you are welcome to email me at info@FitnessSimplified.org or comment below!
What are essential amino acids?
Amino acids are small molecules that chain together to form proteins.
We can produce some of these amino acids on our own. For this reason, they are designated non-essential; meaning we do not need to consume them in our diet.
There are 9 of these amino acids that we cannot produce on our own. Therefore, we must consume them in our diet. These are referred to as the essential amino acids.
These include:
histidine
isoleucine
leucine
valine
lysine
methionine
threonine
phenylalanine
tryptophan
3 of these amino acids have a branched chain as part of their molecular structure.
As a result, they are called the branched-chain amino acids (BCAAs); which is a popular supplement you may have heard of before.
These include:
Leucine
Isoleucine
Valine
Food sources of the essential amino acids
If a food contains all 9 of the essential amino acids, it is considered a complete protein.
If a food does not contain all of the essential amino acids, it is considered an incomplete protein.
Deficiency of these essential amino acids can lead to adverse clinical symptoms, and even death if prolonged for long enough.
Animal foods are well-known for containing all of the essential amino acids, and are therefore considered complete proteins.
This is one of the reasons why animal-sourced proteins are typically considered higher quality.
Protein sourced from plant foods are typically lacking in one or more of the essential amino acids.
As a result, many are considered incomplete proteins.
Some plant foods do contain all 9 of the essential amino acids including, quinoa or soy, but these are exceptions from the rule.
For this reason, people who follow a plant-only diet need to be more conscious of their protein intake than animal eaters.
EAA supplementation: what started the hype behind it?
Some time ago, researchers discovered that one of the BCAAs was responsible for stimulating muscle protein synthesis (the process of building muscle).
It was then thought that intake of BCAAs throughout the day would leave muscle protein synthesis “turned on” leading to increased muscle growth or improved recovery.
Since then, it has been shown to be leucine specifically that activates muscle protein synthesis.
However, there’s still one problem:
There’s two possible reasons why this is happening…
First, muscle protein synthesis had just been “maxed out” for the day (for lack of a better word).
In other words, it’s possible the process of building muscle had hit its limits for a given day.
Second, there weren’t enough of the other essential amino acids (EAAs) to act on the trigger provided by the leucine.
In other words, the call to build more muscle was made but there weren’t enough of the other building blocks available to answer the call.
So, can EAAs help you build more muscle? Or, are they useless?
If the reason that BCAA supplementation fails to provide any benefit when a person eats enough protein in a day is because there weren’t enough of the other EAAs available to answer the call, then EAAs may prove to be helpful.
If the reason that BCAA supplementation fails to provide any benefit when a person eats enough protein in a day is because muscle protein synthesis was “maxed out,” then EAAs may prove to be useless.
As of the writing of this article, no study has looked at EAA supplementation when a person eats enough protein in a day; so it’s hard to say.
I will update this article whenever one is published.
As far as my personal opinion, I can see it going both ways.
If I had to bet, though, I’d bet on them not being useful; however it isn’t a confident bet.
On the one hand, once a person eats 1.6 grams of protein per kilogram body mass, eating more than this does not provide any further benefit.
Even when you double this intake up to 3.2g/kg/day, no further benefit is seen [source].
This would add support to the idea that muscle protein synthesis gets “maxed out” which is in favor of EAAs not being useful.
On the other hand, free-form EAAs have been shown to increase muscle protein synthesis significantly more than intact protein.
3 grams of free-form EAAs have been shown to increase muscle protein synthesis to a greater extent than 20 grams of whey protein [source].
“Intact” means the amino acids are chained together, forming a protein
“Free-form” means the amino acids are not chained together
The reason this is suspected to happen is because the free-form EAAs are taken in much more rapidly than their intact counter-parts, leading to a more potent muscle protein synthesis spike.
This could add support to EAAs proving to be useful.
However, at the same time, this acute spike in muscle protein synthesis doesn’t necessarily mean more muscle will be built long-term.
Take-homes from this
If you are someone who cares about the small percentage increases in progress and don’t mind splurging on products like this, then EAA supplementation might be worth experimenting with.
As far as when to take them, before or after a workout seems to to produce similar benefits [source].
If you are someone who is not overly concerned with optimizing everything there is to optimize, then I would not recommend purchasing an EAA supplement.
At the end of the day, if they are useful, the magnitude of their benefit is likely small and may not be worth the additional financial cost.
Where EAA supplements do seem to be useful
Just because adding EAAs on top of your total daily protein intake might not be very helpful for building more muscle, that doesn’t mean they are totally useless.
The way I see it, there are two current situations where they make sense to purchase.
Training first thing in the morning
Many people choose to do their workouts first thing in the morning.
Most of the time, this means they are performing these workouts in a fasted state.
It is preferable to have some food intake before your training, however most people don’t have the time to eat an entire meal and then wait 45-60 minutes to digest.
This is where an EAA supplement can be helpful.
Because they are free-form amino acids and not intact protein, they can be digested much more rapidly and leave you much less “heavy” feeling.
Ideally, this would be paired with a fast-digesting carbohydrate such as fruit or fruit juice.
Doing this can significantly improve the quality of a workout done first thing in the morning and may lead to greater results long-term; without much more of a time commitment.
Older populations
Sarcopenia is the age related loss of muscle function and muscle size, and leads to or increases the risk of numerous other adverse outcomes [source].
A recent study showed that levels of weakness among older populations is increasing, and recently went above 50% of people from the researchers’ definitions [source].
A large cause of this is a decrease in physical activity throughout the life cycle.
As the average person advances in age, they become significantly more sedentary.
This leads to a subsequent atrophy of muscle due to its lack of use [source].
In addition, though, there does seem to be some degree of “anabolic resistance” associated with age; although there is debate as to the magnitude of this effect.
This essentially means its harder for older people to stimulate muscle protein synthesis [source].
This is where EAA supplements could come in.
Due to their enhanced ability to stimulate muscle protein synthesis, they could prove valuable for older people looking to build or maintain their muscle mass.