 Proteins are essential for life. Already the greek etymon of the word says it: "pròteios" means the first element.
Proteins are really the main constituents of living matter, both from a structural point of view, both for the many specific functions that they carry out.
Digestive enzymes, many hormones, hair, muscles, many carriers in the blood, haemoglobin, skin, antibodies, coagulation factors, bones, all internal organs, are proteins and this just to mention a few of them.
Chemically proteins are long chains of amino acids, placed in several sequences like the pearls of a pretty necklace.
Amino acids in the proteins of the human organism are twenty and the sequence of the amino acid chain of each protein is ruled by the genetic heritage of the individual.
We distinguish the amino acids in essential and non-essential.
The non-essential amino acids can be synthesized by our body from other substances.
The essential amino acids must be introduced compulsorily from the outside with the diet.
The different nutritional value of food proteins depends on their composition in essential and non-essential amino acids.
Meat, fish, milk and eggs contain all the essential amino acids.
Please note that they are all foods of animal origin.
Vegetarians know better than anyone else the concept of complementarity of proteins: indeed, to compensate for the lack of essential amino acids they must necessary eat together pulses and cereals.
The human body does not have a reserve of proteins and must continually synthesize new ones.
To allow this metabolism, 10-15% of calories that we take should come from proteins.
Today a lack of proteins in the diet is still observed in populations of the "third world".
On the contrary, in many industrialized countries many diseases (cardiovascular, cancer, osteoporosis) would be tightly linked to the high percentage of animal protein we daily eat. arininchi 19/08/2008
alimentazione 
crescere un bambino 
salute 
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