Proteins each have their own specific function in the cell. Some build up and organize the cells and other proteins - the enzymes - control various biochemical processes. Many hormones are protein substances and the antibodies are also made of proteins.
To be able to absorb proteins the body have to break them down into amino acids. In our alimentary canal a long line of digestive enzymes that break down proteins into amino acids and peptides are produced. Peptides consist of a few amino acids that are stuck together. Proteins that cause allergy lose their allergy creating effect when broken down into amino acids.
In regards to calories, protein is at level with carbohydrates; i.e. 4 calories or 17 kJ per gram - but it is particularly the protein containt of the food has a filling effect. Approximately 10% of our energy supply should come from proteins. The highest source can be found in meat, fish, eggs, milk, beans, and lentils.
The amino acids are easily absorbed from the intestines and taken to the liver in which the first protein synthesis (the building of proteins from amino acids) takes place. In a human there are more than 50,000 different proteins. The DNA of the cells have the code for which proteins the particular cell should build from the amino acids. All living organisms, however, only use about 20 different amino acids as building blocks for their own production of proteins.
Protein complementing
The nutritional value of a protein depends on its content of amino acids. The higher the content of essential amino acids the higher the nutritional value. Foods with a low share of one or more essential amino acids can with benefit be supplemented with other foods with a higher share of the amino acids that are deficient. Problems with amino acid deficiencies in foods can be avoided by eating a varied diet.
Our need for protein is normally about 1 g. per kg. of body weight. It might be less if the level of utilization is high. If the body lacks protein it will very quickly - before a day has passed - start to break down muscle tissue as it is the body's only substantial protein reserve. The consequence is that the defence against infection and other diseases is weakened.
If we eat large amounts of protein, large amounts of phosphoric acid and sulphuric acid will be created in the body when the proteins are broken down. The body needs basic minerals to neutralize these acids. A large protein intake, therefore, requires adequate amounts of the minerals calcium, magnesium, mangane, potassium and sodium, plus vitamin B6. If, for a long period of time, we eat more protein than the body needs - and especially if the digestion is poor - there are indications that the risk of developing osteoporosis and various forms of cancer is increased.
Who can benefit from a protein supplement
Everyone with a reduced appetite - elderly people, vegetarians, sick people, and people on recuperation, plus athletes.
Also see "Amino acids generally", "Amino acid complexes - Protein supplements", "Branched-Chain Amino Acids", and "Glutathione" in the Health Products category.
