Think the debate over milk"s nutritional value is just a veggie-vs.-animal-foods battle? Well, now there"s a more complex and interesting debate pitting A1 against A2. Confused? Read on.
Most consumers are aware of the controversy surrounding the nutritional benefits of so-called "raw milk."
Proponents of raw (unpasteurized) milk claim that its health benefits are far superior to pasteurized milk to the extent that many advocates insist that the homogenized, pasteurized stuff 99.99 percent of us drink can cause all sorts of health problems.
That debate pits an isolated fringe group against an overwhelming majority of both scientists and consumers, and when on occasion raw milk containing pathogenic bacteria sickens somebody, it only reinforces the extremist stance of the people opposed to the most reliable food-safety technology ever developed.
But like a belief in alien abduction, there"s no convincing raw milk devotees that they should re-examine their beliefs.
Now, however, there"s another milk-related controversy, one seemingly more plausible, but one also being flogged by a small cadre of researchers and their media cheerleaders. It"s based on the theory that many people who suffer from lactose intolerance are not allergic to lactose. Instead, they"re unable to properly digest the A1 protein typically found in milk from Holstein cows, unlike the A2 protein that predominates in Jersey and Guernsey breeds.
The A1 and A2 proteins are different forms of beta-casein, which comprises about 30 percent of milk"s protein content.
But you already knew that.
What I didn"t know, however, is the A2 backstory. It seems that A2 beta-casein mutated into A1 thousands of years ago among certain European dairy herds. Millennia later, cows can now be classified either as pure A2, A1-A2 hybrid, or pure A1. (Both human breast milk and goat"s milk contains only A2 beta-casein).
This controversy over the alleged ill effects of A1 milk first heated up in New Zealand some 20 years ago, thanks to research by Prof. Robert Elliott at New Zealand"s University of Auckland. Elliott theorized that the consumption of A1 milk might explain the high incidence of type 1 diabetes among Samoan children in New Zealand. According to a current story in Mother Jones magazine, he analyzed per-capita consumption of A1 milk and the incidence rates of diabetes and heart disease in 20 different countries and discovered strong correlations.
Of course, correlation is not causation; the etiology of chronic disease is always multifactorial, meaning that factors such as diet, lifestyle and the amount of vitamin D a person metabolizes from exposure to sunlight would influence any correlations between A1 milk and chronic disease.
That didn"t slow down Prof. Elliott, however, and in a 1997 study published by the International Dairy Federation, he demonstrated that A1 beta-casein caused mice to develop diabetes. Elliott"s co-researcher, Corran McLachlan, soon after partnered with wealthy New Zealand businessman Howard Paterson to launch the A2 Corporation.
A cause, or a correlation?
Since then he"s had plenty of support and gotten lots of publicity from several self-appointed health authorities.
"We"ve got a huge amount of observational evidence that a lot of people can digest the A2 but not A1," Keith Woodford, a professor of farm management and agribusiness at New Zealand"s Lincoln University and author of the 2007 book "Devil in the Milk: Illness, Health, and the Politics of A1 and A2 Milk," told Mother Jones. Woodford reviewed more than 100 studies that he said suggest links between the A1 protein and the development of heart disease, diabetes, even autism.
Woodford"s stance is adamant, even though the evidence is less-than conclusive.
For instance: A 2009 study by the European Food Safety Authority reviewed the available scientific literature concerning the health effects of beta-casein in milk and concluded that, "A cause-and-effect relationship is not established between the dietary intake of beta-casomorphin-7 or [its] possible protein precursors and non-communicable disease."
In other words, the A1 protein does not appear to be a causative agent for diabetes, heart disease and cancer, as Prof. Woodford suggested.
That conclusion prompted New Zealand"s Food Safety Minister, Lianne Dalziel, to declare the debate over A1 versus A2 milk resolved, and that it was not necessary for the New Zealand Food Safety Authority to conduct its own scientific review.
That hasn"t stopped A2 Corporation from marketing its a2 brand milk in New Zealand and Australia, where its product line accounts for about 8 percent of dairy product sales Down Under (according to the company). In 2012, A2 expanded distribution through the Tesco chain into Great Britain, where a two-liter bottle now sells at about an 18 percent premium over conventional milk.
A2"s literature explains that the company"s farmer-suppliers use DNA analysis of tail hair from each cow to certify she is producing A2 milk, which is kept segregated throughout processing.
To its credit, A2 Corp. officials have been careful not to overtly suggest that consuming its products would allow consumers sidestep the serious diseases identified in Elliott"s and Woodford"s published research. Instead, they merely emphasize the "digestive benefits" of its fluid milk, fresh cream and infant formula products. Of course, some of that caution is the result of a $15,000 fine the Queensland (Australia) Health Department levied on the company in 2004 for making "false and misleading claims" about the health benefits of its a2 brand milk.
Here"s the bottom line: Given the incredible variability of individuals in any large population, it"s entirely possible that certain people do react severely to the A1 protein fraction when it"s present in milk especially babies, whose digestive tracts are far more permeable. After all, most people could eat an entire jar of peanut butter without incident, while a few sensitive individuals would risk anaphylactic shock merely by sniffing the lid.
Whether or not the science behind A2"s marketing is legitimate, the company is poised to re-enter the U.S. market sometime this year. It seems clear from reading their prospectus that its management believes there are enough American consumers willing to pay a premium for A2 milk to make the launch worthwhile.
Even more telling: It"s now possible to convert a herd of A1-producing cows to A2-producing cows, and selected dairies are doing exactly and test-marketing A2 milk in a number of states.
Might try some myself.
The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.