A protein is a molecule made up of a chain of amino acids. These are provided by food, and can be of animal (meat, fish, eggs) or plant (fruits, vegetables, cereals) origin. What is its role in the body? Update on needs with Dr Corinne Chicheportiche-Ayache, nutritionist.
Definition: what is a protein?
« A protein is a chain of amino acids, the amino acid being the unitary element of the protein » indicates Dr. Corinne Chicheportiche-Ayache, nutritionist. “ These combinations of amino acids form chains that can be very long and thus take time to be digested ,” she explains.
How is it synthesized?
» Proteins are made from amino acids. We can compare proteins with a small train with wagons (amino acids) » explains the nutritionist. Protein synthesis is the term used to designate the process by which a cell succeeds in assembling what is called a protein chain. The information held by deoxyribonucleic acid ( DNA ) allows this cell to proceed with the assembly of amino acids contained within its cytoplasm. This protein synthesis is governed by two major distinct phases. The first corresponds to the transcription of DNA into messenger ribonucleic acid (messenger RNA). Then comes the
What is his role ?
“Proteins have multiple essential roles in our body. One of the most important roles of proteins is bone and tissue construction, ” explains Dr. Chicheportiche-Ayache. Proteins are also essential for cell life. » In our organism, the enzymes are essentially protein, certain enzymes are also immunoglobulins (antibodies) » indicates the nutritionist. They are also the body’s only source of nitrogen.
There are animal proteins and vegetable proteins . Animal-based proteins are found in meat, fish, eggs, seafood, shellfish, and dairy products . 8 amino acids are said to be essential because our body is not able to produce them. » Animal proteins provide all the essential amino acids » informs Dr. Chicheportiche-Ayache.
Plant proteins are found in foods of non-animal origin. They come from plant elements: cereals, legumes, oilseeds, seeds, dried fruits, algae, etc. » Cereals and pulses rich in protein have a more partial protein intake: an amino acid (lysine) is missing in cereals and an amino acid (methionine) in pulses . They must therefore be combined in the same day to have sufficient protein intake, informs the nutritionist. Seaweed and soy provide them with the 8 essential amino acids « , specifies she.
What foods are high in protein?
Foods rich in animal protein are meat, poultry, eggs, fish and seafood, and dairy products. Foods rich in vegetable proteins are soy and its derivatives (Tempeh, Seitan), cereals, pulses, oilseeds (almonds, walnuts, etc.), chia seeds, seaweed (and in particular spirulina).
How much to consume per day?
It is recommended to consume 1g of protein per kilo of weight each day. » Overall, this represents a portion of protein per day: 2 slices of ham or 2 eggs or 150-180g of fish or 120g of meat » indicates the nutritionist. Protein intake should be higher in athletes, pregnant women, people who are burned or undernourished. » We consume too much animal protein, it would be better to consume 50% animal protein and 50% vegetable protein or at least 2/3 animal protein and 1/3 vegetable protein » advises the nutritionist.
Examination of the serum protein level in the blood (normal values, level too low, too high, etc.)
“ The serum protein level is part of protein electrophoresis, ” explains Dr. Chicheportiche-Ayache. The electrophoresis of serum proteins immunoglobulins, albumin and beta 2 microglobulin is a biological test that allows to assess the quality and quantity of serum proteins. It makes it possible to detect and monitor numerous pathologies : inflammatory syndromes, certain cancers, physiological or nutritional disorders, etc. The normal values are:
– Albumin : 40 to 45 g/l.
– α1-globulins: 2 to 4 g/l.
– α2-globulins: 4.5 to 7 g/l.
– β-globulins: 7 to 13 g/l.
– γ-globulins: 5 to 15 g/l.
– Fibrinogen: 2 to 4 g/l.
– Total protein: 50 to 95 g/l.