Conventional wisdom states that drinking milk causes an increase in phlegm. Scientists have generally dismissed the notion, though, since experiments do not seem to bear it out. In one study, researchers noted that even people who were inoculated with the common cold virus did not show any increase in symptoms when they drank milk.
But a new report suggests that those earlier studies suffered from a critical flaw: not all milk is the same.
Certain breeds of cow, contain a protein called beta-CM-7, which has been shown in studies to stimulate mucus glands in the digestive tract. These glands are also found in the respiratory tract, where they are known to overproduce mucus in conditions caused by inflammation, like asthma.
Milk containing the beta-CM-7 protein may stimulate phlegm in the respiratory tract, particularly in people with chronic lung conditions.
there are actually distinct differences in the milk produced by various breeds of dairy cows. A1 cows are “newer” breeds that experienced a mutation of a particular amino acid some 5,000 years ago, whereas A2 cows are the older breeds that do not have this mutation.
Milk solids from milk consist of a variety of proteins, lactose and other sugars. One of these proteins is called beta-casein, and this is the protein of interest when comparing A1 and A2 milk.
All proteins are long chains of amino acids. Beta casein is a chain of 229 amino acids. A2 cows produce this protein with a proline at number 67, whereas A1 cows have a mutated proline amino acid, which converts it to histidine.
The proline in A2 milk has a strong bond to another small protein called BCM 7, which helps keep it from being released.
Histidine (the mutated protein), on the other hand, only weakly holds on to BCM 7, so it is liberated in the GI tract of animals and humans who drink A1 cow milk. Now, BCM7 is a powerful opiate that can have a very detrimental impact on your body.
[Source]
Chapter: Milk :: 29 April 2010
