Amino acids have always been a supplement, in people’s minds, is linked to sports. They are supplements hardly recommended to a sedentary audience or to a person outside the gym environment and in general to physical activity. Yet, the benefits of an addition of amino acids, precisely on these "not particularly active" people, are remarkable. In this article we will see them starting with understanding what are the amino acids and essential amino acids (EAA), in particular.
What are the amino acids
Amino acids are organic compounds composed of nitrogen, carbon, hydrogen and oxygen, along with a group of variable side chains. Our body needs 20 different amino acids to grow and function properly. Although all 20 are important for your health, only nine amino acids are classified as essential [1].
These are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
Unlike non-essential amino acids, essential amino acids cannot be produced by your body and must be obtained through your diet.
There are also several non-essential amino acids that are classified as conditionally essential.
These are considered essential only in specific circumstances such as illness or stress. For example, although arginine is considered non-essential, your body cannot meet the demands when it fights certain diseases such as cancer [2]. That’s why arginine needs to be integrated through diet to meet the needs of your body in certain situations.
Their role in the body
The nine essential amino acids perform a number of different important and varied jobs in your body:
- Phenylalanine: Phenylalanine is a precursor of the neurotransmitters tyrosine, dopamine, epinephrine and norepinephrine. It plays a fundamental role in the structure and function of proteins and enzymes and in the production of other amino acids.
- Valine: Valine is one of three branched-chain amino acids, which means it has a chain that branches off to one side of its molecular structure. Valine helps stimulate muscle growth and regeneration and is involved in energy production.
- Threonine: Threonine is a major part of structural proteins such as collagen and elastin, which are important components of skin and connective tissue. It also plays a role in fat metabolism and immune function.
- Tryptophan: Although it is often associated with causing drowsiness, tryptophan has many other functions. It is necessary to maintain a proper nitrogen balance and is a precursor of serotonin, a neurotransmitter that regulates appetite, sleep and mood.
- Methionine: Methionine plays an important role in metabolism and detoxification. It is also necessary for tissue growth and absorption of zinc and selenium, vital minerals for health.
Leucine: like valine, leucine is a branched-chain amino acid essential for protein synthesis and muscle repair. It also helps regulate blood sugar levels, stimulates wound healing and produces growth hormones. - Isoleucine: The last of the three branched-chain amino acids, isoleucine is involved in muscle metabolism and is highly concentrated in muscle tissue. It is also important for immune function, hemoglobin production and energy regulation.
- Lysine: Lysine plays an important role in protein synthesis, hormone and enzyme production and calcium absorption. It is also important for energy production, immune function and collagen and elastin production.
- Histidine: Histidine is used to produce histamine, a vital neurotransmitter for immune response, digestion, sexual function, and sleep-wake cycles. It is essential to maintain the myelin sheath, a protective barrier that surrounds nerve cells.
As you can see, essential amino acids are at the centre of many vital processes.
Although amino acids are more recognized for their role in muscle development and repair, the body depends on them for much more. That’s why essential amino acid deficiencies can have a negative impact on your entire body, including nervous, reproductive, immune and digestive systems.
Let’s now look at what are the main and possible benefits of EAA integration.
Amino acids and sleep
Tryptophan is necessary for the production of serotonin, a chemical that acts as a neurotransmitter in the body.
Serotonin is an essential regulator of mood, sleep and behaviour.
While low serotonin levels have been linked to depressed mood and sleep disorders, several studies have shown that tryptophan supplementation can reduce symptoms of depression, increase mood and improve sleep [3] [4] [5] [6] [7].
A 19-day study of 60 older women found that 1 gram of tryptophan per day led to increased energy and better happiness, compared to a placebo [8].
Amino acids and exercise
The three essential branched-chain amino acids are widely used to relieve fatigue, improve athletic performance and stimulate muscle recovery after exercise.
In a study of 16 endurance-trained athletes, branched-chain amino acid supplements improved muscle performance and recovery and reduced muscle pain, compared to a placebo [9].
A recent review of eight studies found that integration with branched-chain amino acids was superior to rest in promoting muscle recovery and reducing pain after exhaustive exercise [10]. In addition, intake of 4 grams of leucine per day for 12 weeks has increased strength performance in untrained men, demonstrating that essential amino acids can also benefit non-athletes [11].
Amino acids and sarcopenia
With the term sarcopenia, we refer to muscle loss resulting from inactivity or, normally, with advancing age. The EAA are able to maintain muscle mass by decreasing the phenomenon of sarcopenia. A 10-day study of 22 elderly people at rest in bed gave subjects 15gr of EAA noting a positive balance of protein synthesis compared to the placebo group [12]. These results have also been seen in other studies [13] [14].
Amino acids and weight loss
A positive effect on fat loss has also been seen. This is both in studies in men [15] and in rats [16]. These conclusions still deserve further investigation in the literature, but it seems promising that they will be used in this regard.
Conclusions
The essential amino acids are therefore a very interesting and useful supplement to take. Our advice is to add them to a balanced diet. Therefore a protein intake of 1-1,5gr/kg of protein for the athlete and 0,8-1gr/kg of body weight for the sedentary.
We add a serving of EAA in the morning, one in the evening and one in the drink we sip as we train so that they are conveyed to the best in the muscle and support its growth and repair after exercise!
References:
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4897092/
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4657121/
[3] https://www.ncbi.nlm.nih.gov/pubmed/26805875
[4] https://www.ncbi.nlm.nih.gov/pubmed/18648776
[5] https://www.ncbi.nlm.nih.gov/pubmed/21488845
[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1407729/
[7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4523676/
[8] https://www.ncbi.nlm.nih.gov/pubmed/25572038[9] https://www.ncbi.nlm.nih.gov/pubmed/28177706
[10] https://www.ncbi.nlm.nih.gov/pubmed/28870476
[11] https://www.ncbi.nlm.nih.gov/pubmed/21487148
[12] https://www.ncbi.nlm.nih.gov/pubmed/19419806
[13] https://www.ncbi.nlm.nih.gov/pubmed/19208731
[14] https://www.ncbi.nlm.nih.gov/pubmed/26733764
[15] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3313152/
[16] https://www.ncbi.nlm.nih.gov/pubmed/21872432
