What is A2 milk? It’s a question nutritional consultant Donna Gates asked during a trip to Japan, where she was amazed at how exceptionally good the milk she was drinking tasted. When she discovered it was in fact not the same milk she was accustomed to and was known as “A2 milk,” she began to research the topic. She found out that a woman’s breast milk is A2, and that goats, sheep, and other mammals produce this kind of milk — but not all cows. She learned that A2 milk was produced by cows in Japan, India, France, Australia, and New Zealand. She went to Australia in May 2006, and something on a grocery store dairy shelf caught her eye: cartons of milk with “A2” on the labels.
She took some back to her hotel room and tasted it. It had the same light, fluffy, delicate texture as the milk she had tasted in Japan. She decided to make kefir with it and was amazed at the beautiful result. What, then, is A2 milk?
The Science of A2 Milk
Approximately 30 percent of the protein component in a cow’s milk is beta-casein. Evidence indicates that all cows used to produce milk containing only the beta-casein known today as A2. At some point in history, though, a genetic mutation led to a variant of this protein, giving rise to A1 milk.
The difference between beta-caseins A1 and A2 is a single amino acid. A2 milk has the amino acid proline at position 67 in its strand of 209 amino acids, whereas A1 milk has the amino acid histidine at position 67. A protein must be broken down into fragments — smaller chains of amino acids known as peptides, or residues — in order for the body to process and digest it. During the digestion of A1 milk, a bioactive peptide called beta-casomorphine 7 (BCM-7) is created. Beta-caseins are important in the assimilation of essential nutrients such as iron, calcium, zinc, and copper. As they are digested, they yield a multitude of bioactive protein fragments. Any variation in fragment structure changes how the body digests it. Since human breast milk contains the A2 beta-casein, the BCM-7 formed by A1 digestion is treated as foreign substance in the body, triggering unfavorable reactions.
Health Differences of A2 Milk
A wide range of studies suggest that milk that does not yield BCM-7 (i.e., A2 milk) is associated with reduced risk of heart disease, reduced risk of Type 1 diabetes, no antagonistic effects on certain neurological conditions, and improved immune response, which is critical for newborn infants. The BCM-7 protein fragment resulting from A1 beta-casein digestion is known to have strong opioid (sedative) properties. Numerous international studies have shown other effects of BCM-7, including the oxidation of LDL cholesterol, which can lead to heart disease, the aggravation of neurological disorders such as autism and schizophrenia, and the disruption of the regulation of insulin formation. Research suggests that BCM-7 can cross the blood-brain barrier, reaching the central nervous system in babies, resulting in the apnea associated with sudden infant death syndrome.
There is a genetic test to determine if a cow will produce A2 milk. Bulls can be tested as well to see if they carry the A2 gene. People in the United States drink cows’ milk without even realizing that two different forms exist. We have hundreds of thousands of children moving away from milk because their parents and doctors think it’s bad for them. Donna Gates would like to see children have access to A2 milk.
“I believe that the many people who think they can’t tolerate milk would be able to drink this milk,” she says. Gates is very interested in finding producers who are willing to test their cattle and start deliberately producing A2 milk. She hopes to work with these dairy producers so that she can incorporate this food into her patients’ diets.
By Laurel Hoffman. This article was originally published in the September 2007 issue of Acres U.S.A. magazine.