Milk Peptides - Exciting New Reasons to Drink Milk
~ December 1999 No.88 ~
The digestion process begins when we chew our food into small pieces and it becomes coated with saliva that contains the first of many enzymes that will help break down the food so that it can be absorbed in the intestines.
Milk is a good source of calcium and also protein. The proteins in cow’s milk are complex chains of amino acids that are linked together. The types of amino acids and the order in which they are joined together determines the shape and the use of the protein in the body. Both animal and vegetable proteins are made up of amino acids; the proteins in milk contain several hundred amino acids. Amino acids are the building blocks of proteins. Many amino acids are essential - that is they must be supplied in our diet; we can’t make them. The proteins we eat are the sources of these amino acids
In the stomach, the high acidity - low pH - starts the breakdown of proteins. The acid is able to start to cut the chains of amino acids which causes the protein to lose its shape. The long chains of amino acids are cut into smaller chains called peptides. Peptides can contain as few as five and as many as fourteen or fifteen amino acids. The exciting thing about these breakdown products of proteins is that many of the peptides have been shown to have biological activity - that is they can affect the metabolism of the body.
To date the testing of peptides formed during the digestion of milk proteins has only been carried out in test tube experiments or with experimental animals. But in a mix of peptides formed in the stomach from cow’s milk are included compounds that have antihypertensive, antibacterial, antiaggregating, immunomodulating and antithrombotic effects. This list is very diverse because the peptides formed vary widey in their impact on various metabolic pathways.
Milk is another example of a food that can impact positively on our health and disease fighting mechanisms in the body. Because many of the foods we eat are complex, it is difficult to predict what specific component of the food will be the active ingredient. The recommendation of having a varied diet makes more and more sense as we understand the interaction of food and health
Proteins Found in Milk
alphas- casein, beta-casein, kappa-casein, gamma-casein, lactalbumin, lactoglobulin, immunoglobulins
Essential Amino Acids
tryptophan, phenylalanine, lysine, threonine, valine, methionine, leucine, isoleucine