No, not all plant proteins are incomplete.

I’m sure we’ve all heard, or even studied, that Vegetable proteins are not “complete”, that only animals are, and that they have to be combined with each other. In fact, it is a myth that is still alive, despite being decades obsolete.

People, even toilets, continue to be surprised by this topic, so we are going to dedicate a few lines to it. But first, some basics.

What are proteins and what are they for?

They are nitrogenous substances composed of amino acid chains have various functions, being best known maintenance of body tissues. Although they are also part of the immune system and of many enzymes, they perform transport functions for other substances and can even be used as an energy substrate, although our body prioritizes carbohydrates for this.

And what is an amino acid?

An amino acid is each of the pieces that make up a protein. Imagine that a protein was a train: each wagon would be an amino acid. Thus we could assemble trains with many wagons, with few wagons, with first class and tourist class wagons, with freight wagons… all depending on what we needed the train for. Well proteins work the sameeach one is made up of different amino acids and in different amounts.

What is a “complete protein”?

We call “complete protein” that which has all the essential amino acids in its composition in sufficient quantities.

The essential amino acids They are those that our body is not capable of synthesizing on its own and must obtain them from the diet. Those amino acids are: histidine, phenylalanine, isoleucine, leucine, lysine, methionine, threonine, tryptophan, and valine. In certain situations, other amino acids may also be essential, but that is not today’s topic.

What plant foods have complete proteins?

The soythe chickpeassome types of beanthe pistachiosthe quinoathe Hemp seeds or the amaranth they have “complete proteins”. Spinach also, although the amount they contain is low, about 3g per 100g, so we would have to eat a large amount to obtain a significant protein serving, and it does not seem very practical.

Therefore, we must not only take into account the protein qualityif not also the amount per serving of consumption. And there would still be another concept to assess, which is digestibility, but we will leave that for another article.

This information on the aminogram of foods can be consulted in different sources, one of the most accessible are the USDA food composition tables.

Do the rest of plant foods do not have essential amino acids?

Of course they have all foods have. What happens is that some of them fall a little short.

For example, from legumes that we have not named before, such as lentils, have a little less methionine than the rest of the essential amino acids (we say that they are “methionine-limiting”); the cerealsfor their part, are limiting in lysine and threonine, and vegetables are usually methionine and cysteine.

When we join limiting foods in different amino acids, they complement each other and we obtain complete proteins again, with all the essential amino acids in sufficient quantities. Hence the theory of combine plant foods to obtain complete proteins.

Do they always have to be combined?

No. Eating lentils with rice is just as effective as eating rice and lentils for dinner.

Our body has a “pool of amino acids”, a kind of deposit in the liver. They are stored there and removed as needed.

Therefore, it is not necessary to make food combinations on the same plate, not even in the same meal to ensure “complete proteins”. It is a myth that should already be more than overcome.