The biological value of dietary proteins
For those with less time, at the bottom you can find the most important facts.
Proteins form an elementary pillar of our diet. As an essential main nutrient for the human body, protein gains in importance primarily through individual building blocks. The composition of the respective elements contributes directly to the performance of our biochemical cycle. Due to the lack of the body’s own production mechanisms, certain building units have to be supplied from outside. Especially against this background, necessary protein components that cannot be stored independently should be resorted to as needed.
Easily digestible protein sources have a high biological value
Some knowledge about the evaluation of different protein sources is of fundamental importance for an optimised protein intake. In principle: not all proteins are the same. The reason for this lies in the biochemical function of ingested proteins to participate in building the body’s own proteins. Proteins are differentiated according to their natural composition. Numerous proteins are in a favourable constitution and can thus supply our organism with essential substances.
One guideline here is the biological value. The higher the biological value, the easier it is for the body to process the proteins. For example, a value of one is assumed for egg proteins. Basically, these proteins are considered to be ideally biologically usable.
A distinction is made between animal and vegetable protein sources
The natural composition of a protein source determines the amount of protein we need every day. The higher the bioavailability of individual foodstuffs, the less additional protein our body needs. The decisive factor is which proteins we consume and which of them our body can actively use. It is worth taking a closer look at the classification. This makes it easier to determine which foods have biologically high-quality protein.
In order to be able to take in the daily necessary amount of protein, we can resort to both animal and plant sources. Animal products usually have a higher biological value than various plant sources. The biological value can be increased by combining different foods. The parallel intake of potatoes and eggs (in a ratio of two to one), for example, leads to an increase in biological value.
Plant-based foods are also true protein bombs that should not be neglected. Soya products in particular have proteins that are easy to utilise. These not only act as a useful source of protein, but according to a study from 2018, they can even reduce the risk of prostate cancer in men.
The composition of the individual protein determines the biological value
In order to better understand the gradient of biological utilisation potentials between the individual food sources, knowledge of the chemical structure of proteins is useful. Proteins are composed of 21 different so-called proteinogenic amino acids. A distinction is made between essential and non-essential amino acids. The former must be supplied to the body because they cannot be synthesised by the body itself at any time. Semi-essential proteins, on the other hand, are only needed in certain situations, such as intense physical exertion. The body can basically produce these itself. Logically, the body is not dependent on the supply of non-essential amino acids.
Incidentally, amino acids are linked elements of a longer chain. In their entirety, they ultimately form the protein.
In order to better understand the gradient of biological utilisation potentials between the individual food sources, knowledge of the chemical structure of proteins is useful. Proteins are composed of 21 different so-called proteinogenic amino acids. A distinction is made between essential and non-essential amino acids. The former must be supplied to the body because they cannot be synthesised by the body itself at any time. Semi-essential proteins, on the other hand, are only needed in certain situations, such as intense physical exertion. The body can basically produce these itself. Logically, the body is not dependent on the supply of non-essential amino acids.
Incidentally, amino acids are linked elements of a longer chain. In their entirety, they ultimately form the protein.
A deeper look at proteins can be helpful for a detailed understanding of biological value. Proteins have an ideal value due to the optimal composition of amino acids. The relevant amino acids make the decisive contribution to a high value. Accordingly, essential amino acids in an optimally balanced ratio are reflected in the level of biological value.
Amino acids are also partially in great demand in the context of numerous medical treatments. For example, valine, leucine and isoleucine are used in patients with liver cirrhosis. Certain amino acids are also frequently used in the care of intensive care patients.
Facts, facts, facts
Biological value is a measure of the extent to which a protein can be processed by our body
Animal sources of protein have a higher biological value than plant sources
Certain food combinations can increase biological value
Proteins are composed of a number of amino acids, the optimal combination of amino acids determines their biological value
In medicine, amino acids play a crucial role and can be used as a therapeutic measure on a case-specific basis
Text sources:
(1) Brandenburger / Königshoff, Biochemistry, 2018
(2) Horn, Biochemistry of Humans, 2018
(3) Adam, Nutritional Medicine, 2004
(4) Applegate et al., Soy Consumption and the Risk of Prostate Cancer, 2018
(5) Kurtz / Silbernagl / Pape, Physiology, 2018; Brandenburger / Königshoff, Biochemistry, 2018; Horn, Biochemistry of Humans, 2018.
(6) Holecek, Branched-chain Amino Acid Supplementation in Treatment of Liver Cirrhosis, 2017.
(7) Ginguay et al, Indications and Contraindications for Infusing Specific Amino Acids (Leucine,
Glutamine, Arginine, Citrulline, and Taurine) in Critical Illness, 2016.
Image sources:
(8) Designed by Freepik
