About 15% of the daily intake should come from PRO.
PROs are essential for every process within cells. Many PROs act as enzymes for metabolism and others have structural or mechanical functions, such as those of the cell skeleton. They are also important in intercellular communication and immune system activity, among others (11).
However, we are not only interested in the quantity of protein intake, but also in the quality.
The quality of proteins refers to their biological value (B.V.) (11).
BV is an indicator of the ratio of PRO absorbed from a food, relative to what is ultimately incorporated into the body’s PRO (11).
Proteins are building blocks of nature that are made up of 21 amino acids.
The human body is unable to synthesise 9 of these on its own. Thus, they have to be obtained through the diet and are therefore called “essential amino acids”.
These 9 amino acids and their ratios within a protein determine the B.V. of that protein (8).
When all 9 amino acids are detected -> High B.V.-> assimilation with high efficiency by the muscular system / foods of animal origin (egg, meat, fish) and soy from plant origin (7,8).
When all 9 amino acids are not detected -> Low B.V.-> assimilation with low efficiency by the muscular system / foods of plant origin (except PRO of soy) (7,8)
Some combinations of plant PROs can give us complete, high B.V. proteins.
This is because some of the essential amino acids that are absent or not present in the quantities required by the human body in one plant PRO are supplemented by the amino acids of another.
For example, legumes are a good source of PRO, low in biological value as they lack some of the essential amino acids. However, many of these amino acids are found in cereals (rice, bread, oats).
Legumes + cereals (e.g. lentils) = PRO high biological value (10)