THE IMPORTANCE OF ESSENTIAL AMINO ACIDS

You've probably heard that eating a plate of lentils with rice is very beneficial, or that quinoa is a superfood... Well, this has a scientific basis and is related to proteins and their composition.

As you probably already know, proteins are one of the macronutrients that are present in food along with carbohydrates and fats. They carry out many functions in our body, including energy supply, transport, regulation and mediation (neurotransmitters and hormones), structural (in cell membranes), enzyme formation, defensive (antibodies and fibrinogen), etc. However, animals do not have specific protein reserves (although in adverse situations they can be used as a reserve energy substrate) so we must maintain a balance between supply and elimination in order to cover all functions (Dynamic metabolic balance).

Figure 1. Adapted from FAO (2007). Guide for the evaluation of food quality and safety. Available at: https://www.fao.org/ag/humannutrition/35978-02317b979a686a57aa4593304ffc17f06.pdf

Now let's focus... What does this have to do with amino acids? Proteins are made up of amino acids and their diversity is based, in part, on the combination of the 20 existing amino acids that look like this:

Illustration 2. Own elaboration

A good analogy is that amino acids are the pearls that make up a necklace, which would be the peptide or protein.

Amino acids can be classified according to different criteria, but in nutrition they are classified as essential and non-essential amino acids. The essential ones (9) are those that we have to provide through the diet because we do not have metabolic mechanisms that produce them.

Figure 3. Adapted from Healthline. Essential Amino Acids: Definition, Benefits, and Food Sources. Available at: https://www.healthline.com/nutrition/essential-amino-acids.

So… How can we get them through our diet?

In fact, we can get our protein intake from a multitude of foods, but not all proteins are equally complete and this depends on whether or not they contain all the essential amino acids. Eggs, for example, are one of the foods that contain complete proteins, however, foods such as cereals or legumes contain incomplete proteins because they lack one of these essential amino acids (limiting amino acids). However, our daily diet is not based on consuming isolated foods, so protein supplementation normally occurs, which is the combination of foods that contain proteins with different limiting amino acids, for example, legumes (limiting in methionine) with cereals (limiting in lysine), in such a way that we ingest all the essential amino acids.

However, we must not forget that a complete protein is not the same as a protein of high biological value or high quality, because, although the presence of all essential amino acids is a parameter to take into account, other parameters such as digestibility, nitrogen retention or protein efficiency also have an influence.

In conclusion, the easiest way to get them is through a varied diet, since foods such as dairy products, lean meat, fish and eggs contain all the essential amino acids. We can also combine different sources of vegetable protein such as legumes, whole grain cereals, nuts and seeds to achieve protein complementation.

Written by Maria Caballero

Pharmaceutical