What are the 9 essential amino acids that we have to look for in foods (and where to find them)

Amino acids are essential for human life.

It could be said that they are the brick that builds the proteins.

Although humans are made of about 250,000 different proteins, these are composed of only 20 amino acids.

Our body can make 11 of them.

The other nine are the so-called essential amino acids. They can not be synthesized in our body, so we have to get them in food.

They are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

Dr. Javier Marhuenda Hernandez, expert of the Spanish Academy of Human Nutrition and Dietetics, explains essential amino acids can be found distributed in all the foods that we have available to make our diet.

However, the important thing is to incorporate these nine amino acids simultaneously, and this is where the difficulty lies, since most foods do not have all the essential amino acids in sufficient quantity.

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Image caption Amino acids are the brick of proteins

“We have to differentiate between these complete proteins, which have all the essential amino acids in sufficient quantity, and incomplete, when at least one essential amino acid is not in sufficient quantity to satisfy our needs,” explains Dr. Marhuenda.

At BBC Mundo we have compiled a list so you know which foods are rich in amino acids and which ones may be missing from your diet.

Food of animal origin

Some foods such as lean meats, eggs, milk and its derivatives contain the nine essential amino acids and also the 11 non-essential amino acids required by our body to function properly.

“Foods of animal origin have proteins of high biological value and provide us with all the essential amino acids in one single step, ” says Dr. Marhuenda.

Foods rich in isoleucine, valine, leucine, phenylalanine, threonine, methionine, histidine and lysine are meats and fish such as pork, chicken, veal, salmon, grouper, tuna and sardine.

Foods rich in tryptophan are poultry such as chicken, turkey and rabbit and fish such as salmon, sardines, scallops, grouper, cod and tuna.

Milk and its derivatives , especially cheese, also contain virtually all amino acids.

And the egg , especially the egg, contains amino acids such as isoleucine and valine,

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Image caption Eggs are a great source of amino acids

Does this mean that we should only eat proteins of animal origin?

Absolutely not , says Dr. Marhuenda.

“The intake of protein of animal origin (despite having all the essential amino acids) involves the intake of high amounts of fat , which does not happen with plant proteins,” he explains.

Vegetarian food

The dietitian-nutritionist María Velasco explains that there are some foods of vegetable origin that do not contain the nine essential amino acids, but we can complete them by combining them without the need to incorporate a food of animal origin.

“If you have been told that complete proteins are only acquired in foods of animal origin, this is a myth that we must leave behind, because not all proteins of plant origin are incomplete,” says the nutritionist.

Velasco explains that chickpea, soybeans, some beans, buckwheat, quinoa, amaranth, hemp seeds and pistachios contain all the essential amino acids.

But for example lentils have a limited amount of the essential amino acid methionine and cereals, such as brown rice for example, contain little lysine and threonine.

Therefore, if we make a combined plate of lentils (rich in lysine, low in methionine) with brown rice (rich in methionine and low in lysine) we will get a plate with complete protein.

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Image caption You do not need to eat meat to consume all the amino acids: you can do it by mixing vegetables and legumes

“But beware, there is no need to combine it at the moment, if you do not want to, you can also distribute it at meals during the day,” adds Velasco.

“That is to say, you can take lentils in the food and brown rice at night, since our liver will go on stocking and offering our body the essential amino acids when it is needed”.

Dr. Marhuenda explains that it does not make much sense to focus on the intake of specific foods to meet the needs of a single essential amino acid. What we have to do is to maximize the range of foods we eat so that we can eat them all at once.

Nutritionist Velasco states that incorporating a variety of foods every day such as fruits, vegetables, whole grains, nuts, seeds, animal and vegetable proteins and healthy fats is essential for our body to function properly.