What is beta casein?
Beta casein makes up a third of the nutritionally important protein in cow’s milk. As well as being a rich source of amino acids it delivers minerals such as calcium. As with many proteins in nature, beta casein comes in a number of naturally occurring forms or genetic variants, which can be seen here.
What is A2 beta casein?
A2 is one of the most common forms of the cows’ milk protein beta casein.
It has been identified by researchers as the progenitor, or original form of beta casein which the other forms of beta casein evolved from. (eg A1, A3, B forms of beta casein)
What is different about A2 beta casein?
The difference between A2 beta casein and the other common form A1 beta casein is a single amino acid in a protein chain of 209. At position 67 of the chain A2 has a Proline type of amino acid, whereas A1 has a Histidine at position 67. This one amino acid change results in the A1 and A2 proteins being digested into different protein fragments, with differing biological effects.
Population studies have shown that drinking milk with high levels of A2 beta casein shows promise in reducing the risk of a number of conditions.
For example, intake of milk high in A2 beta casein has been linked with a lower risk of heart disease and type 1 or childhood diabetes. Unlike A1 and other related beta caseins, the digestion of A2 does not produce the protein fragment linked to aggravating symptoms of autism.
What proof is available that A2 beta casein has benefits?
In recent years, many studies have linked milk naturally enriched with A2 beta casein to a lower risk of some diseases such as heart disease and childhood diabetes. Please follow this link to such studies.
How much A2 beta casein do you need to eat to make a difference?
To date, no nutritional authority has published recommendations for A2 beta casein intake. More research is needed before A2 beta casein's full public health benefits can be determined and intake guidelines developed.
Milk should be part of the 3 servings per day of dairy food suggested by the Food Guide to Healthy Eating promoted in many countries.
How is A1 beta casein linked to certain conditions?
A digestion product of A1 beta casein and its related forms, BCM7, has been linked to an increased risk of childhood diabetes, heart disease and aggravation of symptoms in autistic and schizophrenic patients.
Are there products other than milk that contain A2 beta casein?
Any product containing milk proteins or casein is likely to contain A2 beta casein at varying and undetermined amounts.
Does any medical body or organization endorse A2 beta casein?
The New Zealand Food Safety Authority reviewed the research relating to the beta caseins in 2004. They did not endorse, but acknowledged that there is compelling research to date and there is a strong need for further research to determine the specific benefits associated with A2 beta casein. Please follow this link to a Lay Summary of this report.
What other research is being conducted?
Several such studies are now underway in different parts of the world. Researchers hope to determine the role dairy products and A2 beta casein play not only in health and nutrition but also in disease prevention.
How can I get the results of the future studies?
Abstracts to published studies relating to beta casein variants are linked to by the research pages or can be accessed directly from PubMed databases hosted by the National Library of Medicine and National Institute of Health using key words “beta casein” and “a2 beta casein”.