| 10 minutes

Biological value: efficient turnover of dietary proteins

Topics at a glance

1. Proteins: building materials of life

2. But not all proteins are the same

3. Proteins: It's all in the mix

4. Soya protein: Everything in it

5. Proteins: Everything fit

1. Proteins: building materials of life

Protein is a biological molecule with multiple functions. Proteins give life (Greek protos: "first-class"); they are basic elements of our body. Unlike carbohydrates and non-essential fatty acids, proteins cannot be replaced by other nutrients. Protein deficiency threatens, among other things, brittle bones and a weak immune system. Proteins, on the other hand, hardly serve as an energy source. Only with prolonged calorie deficiency or intensive endurance exercise, the body resorts to muscle protein.

We need protein above all as a building material. Cells and tissues, skin and organs, skeleton and muscle strength: only with proteins do we form and maintain them. Proteins also form signaling substances such as enzymes, hormones, antibodies, coagulation factors and transport proteins.

The digestion of proteins – what happens?

The protein that we ingest with food is broken down in the digestive tract into its smallest components, the so-called amino acids. During this process, the complex protein structures are first dissolved. This produces so-called peptide chains, a string of up to 100 amino acids. In the next digestion step, these peptides are further cleaved until only individual amino acids and small peptides are left at the end. Only these smallest compounds and amino acids can be absorbed into the blood. Through the intestinal mucosa, they enter the portal vein, a blood vessel that transports all nutrients absorbed from the intestine to the liver. This builds up various proteins from it or releases them to the blood for further transport into the tissue.


2. But not all proteins are the same

We now know that proteins consist of amino acids. The number and combination of amino acids determine how effectively we convert a dietary protein into body protein. Central to this is the content of essential amino acids.
In order for the body to be able to convert dietary protein into the body's own protein, all so-called essential amino acids (AS) must be regularly supplied to it in sufficient quantities with food, as it cannot produce these essential AS itself.

In order to evaluate the protein quality of a protein source in comparison to other sources, in addition to the amino acid content, its digestibility is checked.

The most common concepts for protein assessment:

  • Biological valence (BW)
  • Chemical Score (CS) or Amino Acid Score (AAS)
  • Protein Digestibility Corrected Amino Acid Score (PDCAAS)

Let's take a closer look at the amino acid score (AAS) or chemical score (CS). The chemical score indicates how efficiently body protein can be built up from dietary protein. The chemical score of Almased is 158, which means that the multicomponent protein can be converted particularly efficiently into body protein, i.e. muscle protein.


3. Proteins: It's all in the mix

Those who combine vegetable and animal proteins in the right proportion combine the advantages of both protein groups. Half to two-thirds of the combination proteins should ideally come from plant sources.

In multi-component proteins, the amino acids complement each other, the biological value of the combination protein exceeds that of the individual proteins. This applies to combinations of legumes with eggs, cereals or milk as well as to the mix of meat or fish with other protein sources. But there is also a disadvantage:

The biological value "sees" only the proteins, but not also fats and carbohydrates contained in the protein source. The protein content of a potato, for example, is only 2%. So you would have to eat far more potatoes than eggs to achieve a biological value of 136 (see table).

Examples of the biological valence (BW) of multicomponent proteins

(whole egg = 100 [reference protein])*:

Protein Sources Mixing ratio BW
Potato + Whole Egg 64 : 36 136
Whey + Potato 70 : 30 134
Milk + Wheat 75 : 25 125
Whole Egg + Soya 60 : 40 124
Whole Egg + Milk 76 : 24 119


*Mixed ratio based on the protein contents, not on the amount of food used.
Example: 64 parts potato protein + 36 parts whole egg protein = BW of 136.


4. Soya protein: Everything in it

Soya is a protein bomb and – measured by its natural protein content – the vegetable protein source with the highest biological value. The small bean has all the amino acids from which our body forms proteins. So also all essential amino acids. Thanks to its short-chain molecular structure, soya protein also enables rapid absorption: we utilise it as well as animal proteins and extract just as much body protein from it.

If you look at its digestibility when assessing protein quality, soya protein achieves the best value in the protein comparison.

Examples of protein quality taking digestibility into account:

Protein Sources Biological valence (BW) Protein Digestibility Corrected Amino Acid Score (PDCASS)
Almased 158 1,0
Whole egg 100 1,0
Whey protein (concentrated whey protein) 100 1,0
Cow milk 85 1,0
Soya flour 84 1,0
Beef 87 0,9
Potato 96 0,6
Rice 82 0,6
Corn 72 0,5
Wheat 59 0,4
Beans 73 0,4


5. Proteins: Everything fit

More and more athletes are turning to multi-component proteins. Those who combine vegetable and animal proteins combine the advantages of both protein groups. The amino acid profiles complement each other. The biological value exceeds that of the individual components. At first glance the inconspicuous powder has it all: Almased combines high-quality proteins from soya and skimmed milk yogurt and thus achieves a high biological value (CS 158) and bioavailability.
Thanks to the shakes, the proteins that are important for athletes are delivered.

Proteins contribute to the maintenance and increase in muscle mass. In addition, protein-rich foods for athletes provide the important branched-chain amino acids valine, leucine and isoleucine, which are particularly necessary for protein building, especially for the development of muscles.


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