Branded Resources

Milk: Why American Milk Is Different

July 25, 2017   /
Elaine M. Hinzey, RD, LDN

Note: A1 protein also is known as A1 beta-casein, and A2 protein also is known as A2 beta-casein.

It was recently speculated that A1 protein, most often found in milk produced by Holstein cows, is to blame for symptoms of “lactose intolerance.” A1 is not as prevalent in milk from Jersey, Guernsey, and most Asian and African cows; in these cows’ milk, the A2 protein is in highest concentrations. Goat milk and human milk contain only A2 protein, while modern cows are purely A2, purely A1, or a mix of A1 and A2.

An Aukland-based company, A2 Corp, has sold A2 milk in New Zealand and Australia for the past 10 years, and it now accounts for 8% of Australia’s dairy market. In 2012, A2 Corp introduced its milk in the United Kingdom, where it sells for about 20% more than conventional milk. A2 Corp recently has announced it will expand into the American market in the near future.

A review completed by the European Food Safety Authority in 2009 found no link between A1 milk and gastrointestinal symptoms. The Australia Queensland Health Dept fined the marketers of A2 milk $15,000 in 2004 for making false and misleading claims regarding the health benefits of A2 milk.

Some people have pointed the finger at A1 for increasing the risk of a large number of health conditions, including heart disease, diabetes, and autism. A1 protein releases an opioid (BCM7) when digested. This excerpt from a letter published in the September-October 2012 issue of the Indian Journal of Endocrinology and Metabolism succinctly summarizes the concerns:

BCM7 is suggested to be associated as a risk factor for human health hazards as it can potentially affect numerous opioid receptors in the nervous, endocrine and immune system. It is also known to be an oxidant of low dietary lipoproteins (LDL) and oxidation of LDL is believed to be important in formation of arterial plaque. Epidemiological evidences claim that consumption of beta-casein A1 milk is associated as a risk factor for type-1 diabetes, coronary heart disease, arteriosclerosis, sudden infant death syndrome, autism, schizophrenia etc.1,2 A broad range of studies from American and European investigations has shown reduction in autistic and schizophrenic symptoms with decrease in A1 milk intake.3 Further, animal trials have also supported the linking of type-1 diabetes to milk exposure in general and A1 beta-casein in particular.

Populations, which consume milk containing high levels of β-casein A2 variant, have a lower incidence of cardiovascular disease and type-1 diabetes. The A1/A2 hypothesis is both intriguing and potentially very important for public health if it is proved correct. It should be taken seriously and deeper research is needed to verify the range and nature of BCM7 interactions with the human gastrointestinal tract and whole organism. This requires more of animal trials and generation of data on human subjects having the problems related to A1/A2 beta-casein milk consumption.

  1. Laugesen M, Elliott R. Ischaemic heart disease, type 1 diabetes, and cow milk A1 beta-casein. N Z Med J. 2003;116(1168):U295.
  2. Tailford KA, Berry CL, Thomas AC, Campbell JH. A casein variant in cow’s milk is atherogenic. Atherosclerosis. 2003;170(1):13-19.
  3. Cade R, Privette M, Fregly M, et al. Autism and schizophrenia: intestinal disorders. Nutr Neurosci. 2000;3:57-72.