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"Every body needs milk" – or does it? Or are some types of milk more favorable than others for specific people? I tend to favor the latter statement after research that I have uncovered. I am not going to reconstruct the original research of the beta-casomorphin-7 (BCM-7) molecule. This is the result of tireless work by many scientists. I am just going to try to bring their hard work together and illuminate the big clinical picture.
The key information stems from published scientific papers that will be listed. Some dairy people are not interested in having this information disseminated. They think that it will damage their industry. I think that this information can help more people become tolerant of ingesting dairy products, which in the long run will only benefit their industry. Anyway, integrity in research requires that we need to follow whatever path the evidence leads to. I call this the scientific attitude. Unfortunately, this isn't always the case in real life. Ask Nancy Wertheimer, who died in 2008 and initially linked electromagnetic fields to cancer, about that sad state of affairs.1 She was vilified as a bad scientist (even though she was just asking a question that came about because of research she had conducted) or a woman cursed with PMS.
First, let's begin with some Milk 101 basics.2 Cow's milk can be broken down into 7 basic ingredients (Figure 1).3 The most prolific is plain old water at approximately 88%. Next is protein at about 3% to 4%, of which 80% or so is casein and 20% or so is whey and can vary from breed to breed. Milk proteins also contain all 8 essential amino acids required by humans. Depending on the type of milk, the fat content varies from 3% to 6%. In around 5% of milk lurks the potentially evil carbohydrate lactose. Next, milk contains a fair amount of the water-soluble B vitamins and vitamin C, a large portion of which are destroyed during pasteurization. Cow's milk also contains vitamins A, D, E, and a small amount of K, which are mostly removed in our society's quest to consume lower-fat or nonfat products. Finally, there are minerals in milk, primarily calcium and phosphorus. Unfortunately, soluble and assimilable calcium in milk is reduced again via that unnecessary step of pasteurization.
The serum (whey) protein family consists of approximately 50% ß-lactoglobulin, 20% a-lactalbumin, and a smattering of less prevalent molecules: blood serum albumin, immunoglobulins, lactoferrin, transferrin, and many minor proteins and enzymes. Each whey protein has its own characteristic composition and variations. Whey proteins do not contain phosphorus. They do contain many amino acids that have sulfur, which form disulfide bonds within the protein. Denaturation can break the disulfide bonds and is an advantage in yogurt production because it increases the amount of water that the proteins can bind, which improves the texture of the yogurt.
The casein family of protein consists of several types of caseins: alpha (a), beta (b), and kappa (k) caseins. The high phosphate content of the casein family allows it to associate with calcium and form calcium phosphate salts. The abundance of phosphate allows milk to contain much more calcium than would be possible if all the calcium were dissolved in solution. Casein proteins provide a good source of calcium for milk consumers if the milk is not pasteurized.
Also, as a result of where caseins reside in milk, they will only be present in the milk-solid portion of cow's milk. They are not present in the fat portion and will, as a result, not be present in butter. In addition, caseins are not present in the liquid portion or the whey. Butter and whey products will not have beta-caseins and thus will not cause problems in individuals who have problems with A1 milk.
A2 versus A1 Milk and Beta-Casomorphin-7
Numerous references have begun to reveal how diseases, such as type 1 diabetes and cardiovascular disease, are linked to a tiny protein fragment that is formed during the digestion of the A1 beta-casein, BCM-7. This milk protein fragment is produced by cows in the US, New Zealand, Australia, and many other Western countries. Milk that contains A1 beta-casein is known as A1 milk, whereas milk that does not is called A2 milk. Originally all milk was A2 until a mutation affecting Holstein cattle occurred some 8000 years ago.4 This mutation has been passed on to many other breeds, because Holsteins have been used to genetically improve the production of most other breeds. Herds in much of Asia, Africa, and parts of southern Europe remain naturally high in A2 cows. Also, interestingly, the human beta-casein molecule consists only of the A2 type, which means that breast milk releases no BCM-7. In addition, human milk contains primarily whey proteins, whereas cow's milk has about 80% of its protein as casein. Finally, goats and yaks only produce A2 caseins, and most sheep milk is A2.
A2 beta-casein is found in all types of bovine animals, including all Western, African, and Indian cattle and water buffalo. A1 beta-casein is carried by some cows of European breeds, all of which belong to the subspecies Bos taurus.5 African and Asian cattle belong to the Bos indicus subspecies. However, the prevalence of the A2 and A1 beta-casein allele varies between cow herds and also between countries. For instance, a recent study on the beta-casein allele frequency in indigenous Indian cattle (Bos indicus) and river buffalo breeds reported 99% to 100% presence of the A2/A2 genotype in its indigenous cow and buffalo breeds.6 The same study also reported an absence of the A1/A1 genotype in indigenous Indian cow and buffalo breeds. Turning to European breeds, the Holstein, the most common dairy cow breed in Australia, Northern Europe, and the US, carries the A1 and A2 beta-casein alleles in approximately equal distribution. Jersey herds typically have an A2 allele frequency somewhat higher than this, but with considerable between-herd variation. The Guernsey breed has an A2 beta-casein allele frequency of more than 90%.7
The difference between the A1 and A2 type beta-casein variants is a single amino acid substitution at the 67th residue of the 209-amino acid beta casein protein chain (Figure 2).8 This difference in structure results in A1 beta-casein. The beta-casein protein consists of 209 amino acids strung together. The sole difference between A1 and A2 amazingly takes place at amino acid position 67, where histidine is substituted for proline. The proline forms a tight bond with amino acids on either side of it, but histidine does not. In our digestive tracts, because of the weakness of the peptide bonds with histidine, a peptide consisting of 7 amino acids breaks off. This peptide is BCM-7 and is also an opioid peptide.9
A recent study in humans has confirmed that BCM-7 is produced in the digestive system following the intake of milk casein protein.10 This study found detectable bovine BCM-7 in the small intestinal effluents of adults fed 30 grams of milk casein protein. BCM-7 has the demonstrated potential to elicit opioid activity via its affinity to mu-opioid receptors on a range of tissues and systems including the digestive tract, neurological system, and immune system.11–15 Giving naloxone with A1 milk will neutralize those opioid properties.16 BCM-7 can also be hydrolyzed further to produce the shorter exorphin with greater opioid receptor binding affinity, beta-casomorphin-5 (BCM-5).17
Due to the large size, it should be difficult for BCM-7 to pass through the gastrointestinal mucosal barrier.18 Many Americans suffer from leaky gut syndrome, which unfortunately facilitates the entry of BCM-7 into their bloodstreams. To possibly confirm this association, BCM-7 has been found in the urine of some people diagnosed with leaky gut. BCM-7 is also released when milk is pasteurized before it can be digestively produced in our guts. The vast majority of milk in the US is pasteurized.
Ischemic Heart Disease
There is epidemiological evidence that links A1 beta-casein and ischemic heart disease (IHD) and also pharmacological evidence linking A1 beta-casein to oxidation of LDL. Let us look at epidemiology first.
Corran McLachlan discovered some very interesting information on the epidemiological connection between A1 milk and IHD. In Figures 3 and 4, WHO 1990 IHD death rate data for males over 65 years old and females over 65 years old are presented against A1 consumption (excluding cheese).19 The results were remarkable. The correlation between IHD and A1 beta-casein consumption was very high, at 0.84 for men and 0.73 for women. The statistical probability here is less than 1 in a 1000.
The rationale behind the exclusion of cheese is that the subsequent enzymatic action that takes place as cheese ages causes alterations in the casein structure. This leads to chemical changes in individual casein molecules, which decreases the amount of BCM-7 available to be absorbed. Several people have confirmed the absence of BCM-7 in a variety of cheeses.20,21 Thus, the release of BCM-7 is much lower from cheese than from fresh milk.
There also exists a significant correlation for A1 beta-casein consumption and IHD mortality in 8 states of the former West Germany (Figure 5).22 Regional variations in b-casein A1 consumption may be estimated in West Germany, where cattle breed distribution data by state have been recorded since the 1950s, and breed distribution remained constant from 1951 to 1984.23,24 The daily consumption of the b-casein A1 allele was calculated using 1965 breed distributions and the FAO consumption data. They show a statistically relevant relationship between the amount of A1 casein consumed and the IHD death rate/100,000 people from 1977 to 1979 in males of all ages.
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