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Proteins II Good day to all our subscribers, As promised last week, lets explore the role of amino-acids in our diet ( and well-being ). An amino acid is simply a substructure of a protein compound. You can think of protein as being chains of amino acids that are linked together to form a structure. In many cases, several different types of amino acids are in the same protein molecule. It is these amino-acids that are important to the body, and this is what the body uses protein for. Many different proteins are known, but all of them are constructed from 23 principal amino acids. These amino acids are the building blocks of all vegetable and animal protein. A molecule of protein may contain as many as several hundred or even thousands of these amino acids. These amino acids are linked together within the protein molecule in a unique fashion known as peptide linkage. A specific protein contains a variety of amino acids linked together in a sequence specific to that protein. The body cannot use or assimilate protein in its original state as eaten. The protein must first be digested and split into its component amino acids. The body can then use these amino acids to construct the proteins it needs. The ultimate value of a food protein then, lies in its amino acid composition. It is the amino acids that are the essential nutrients. Amino acids are the end products of protein digestion. When protein is eaten, enzymes in the stomach and small intestine begin to break the linkage within the protein molecule and produce shorter and shorter chains of amino acids. Eventually, the amino acids are in a simplified enough chemical form so that they can pass through the intestinal walls in the bloodstream. They are then carried by the portal vein to the liver for elaboration and passed on to the blood, lymph and cells. The cells synthesize the amino acids into protein as required. This simplified description of the digestion and assimilation of protein applies to Exogenous protein. This is the term used for protein obtained through the diet or from outside the body Proteins may also be obtained from within the body. This is called Endogenous proteins. Endogenous protein does not come directly from the foods we eat, but from the synthesis of proteins from within the body. Obtaining protein from the diet is common knowledge. The fact that the body can synthesize protein from its own proteinaccous wastes, however, is not widely known. As the body's cells undergo their natural catabolic processes, they produce proteinaccous waste in the form of spent cells and other by-products of their own metabolism. These proteinaccous products enter the lymph fluid. Other cells in the body are able to ingest these spent proteins and to digest them in "vesicles"("stomachs") of their own formation. The body's cells are thus able to break these proteinaccous wastes down into amino acids and use them to synthesize their own protein. Endogenous protein ( or proteins from within the body ) is an important source of amino acids that is often overlooked by conventional nutrition writers. Many times, up to 2/3 of the body's total protein needs are supplied through endogenous protein and not from exogenous dietary sources. From the digestion of proteins in the diet and from the recycling of the proteinaccous wastes, the body has all the different amino acids circulating in the blood and or lymph. This continually circulating available supply of amino acids is known as the amino acid pool. The amino acid pool is like a bank that is open 24 hours. The liver and the cells are continually making deposits and withdrawals of amino acids, depending upon the concentration of amino acids in the blood. When the number of amino acids is high, the liver absorbs and stores them until needed. As the amino acid level in the blood falls due to withdrawals by the cells, the liver deposits some of the stored amino acids back into circulation. Phew.Is it not fascinating all what is happening, unbeknown to us, in our body? We certainly owe treating it with respect! Next week will be the conclusion of " the protein factor " Wishing you all an enchanted week, The Crazy Nut Team