Proteins are essential to all living organisms. They play a role in numerous bodily functions such as immunity and respiration.
A protein is made up of amino acids. There are 20 amino acids. Of these 20 amino acids, 9 are essential. In other words, they are not manufactured by our bodies. They must therefore be supplied by food.
But in which foods can we find proteins? Which proteins are best absorbed by the body?
Animal proteins
Animal proteins are found in meat and fish, as well as in food products such as milk and eggs.
Animal proteins provide all the essential amino acids and have a very balanced composition.
On the other hand, when ingesting foods rich in animal proteins, other micronutrients such as vitamins and minerals are ingested, helping to absorb the proteins. This is known as the matrix effect.
Animal proteins are highly digestible. In other words, they are very well absorbed.
Plant proteins
Plant proteins are mainly found in cereals, legumes and oilseeds.
In cereals, lysine, an essential amino acid, is present in limited quantities. And in legumes, methionine and cysteine, two essential amino acids, are present in limited quantities.
To provide all the essential amino acids, it is therefore necessary to vary plant protein sources.
As far as digestibility is concerned, plant proteins are much less digestible than animal proteins. This is because plant proteins are made up of molecules (polyphenols, tannins, etc.) that limit protein digestion.
All essential amino acids must be provided, whether from plant or animal sources. Food preparation and cooking methods can increase or reduce protein digestibility, so it's best to vary sources and diversify your diet.
Protein deficiency can be dangerous to health, but so can overdosage, which can lead to kidney or liver disease.