A2 milk stands out from the herd

[Guest guest]

THREE years ago n dairy farmers Wayne, and Mulcahy made what could certainly be viewed as a risky business decision.

They spent hundreds of thousands of dollars to start the labor-intensive process of converting their entire herd of cows. In a few years, the only milk produced on their Kyabram farm will be a variety known as A2, named for an ancient version of an ordinary cow gene.Because the Mulcahys wanted to continue selling regular milk - and earn a premium from the A2 milk they were already producing - they've gone to considerable lengths. The process has involved genetically testing their cows, and then segregating them from the rest of the herd. They have to be milked separately, and the milk has to be stored and processed separately. The family purchased additional storage vats and equipment, and had to be particularly diligent to ensure that none of the cows strayed into the other herd.

So why the extra efforts?

It has to do with a protein, a compound that's important to building and regulating the body. A tiny protein found in ordinary milk might not seem a likely villain, but some experts warn that under certain circumstances, it can be. More than 100 scientific papers have drawn links between A1 beta-casein, a protein found in cow's milk, and serious illnesses including type 1 or juvenile diabetes and heart disease, and to a lesser extent, autism and schizophrenia.

But just how strong the evidence is - and what should be done as a result from a public health perspective - has been the subject of debate.

In 2002 the Mulcahys happened upon a stock agent connected with A2 Corporation, the company that holds the patents for genetic testing of cattle and owns the A2 Milk trademark, a guarantee that the cow does not produce A1 beta-casein. They researched the claims the group made, and found them compelling.

And they had some experience of their own. 's young daughter, andra, would become violently ill within 20 minutes of consuming any dairy product, leading her doctor to conclude she was "lactose intolerant". But after hearing anecdotes of people who couldn't tolerate "normal milk" but didn't seem to have problems with A2, her parents decided to give it a shot.

Sure enough, andra could drink A2 milk without getting sick.

"Our experience with andra not only convinced us to convert to A2 cows, we believe the whole Australian dairy industry will eventually move that way too," says.

Every litre of milk contains about two teaspoons of beta-casein, usually a mix between A1 and A2. A2 is the original type, found in herds of cattle thousands of years ago, but over time a natural mutation occurred in some European cattle, and A1 beta-casein developed, says Woodford, professor of farm management and agribusiness at Lincoln University in New Zealand, and the author of a book on the subject, Devil in the Milk.

According to Woodford, the genetic difference between the two beta-caseins is tiny, but the difference in outcome is enormous. "The beta-casein has 209 amino acids (the building blocks of proteins) and the difference between A1 and A2 is just one of these," he says.

That is, the amino acids appear in a fixed sequence, and while A1 milk has an amino acid called histidine at one position, A2 milk has a proline. Woodford says that histidine changes the way the protein is digested, releasing a protein fragment called beta-casomorphin 7, or BMC7 for short. BMC7, he says, is a powerful opioid-a narcotic. It's also an oxidant. In laboratory tests BMC7 modifies cholesterol to a form that creates dangerous fatty plaques that line artery walls.

There have been no studies confirming a link between A1 and milk intolerance, but Woodford says anecdotal and observational evidence shows that a number of people who are intolerant to milk and automatically assume it's the lactose causing the problem, may in fact be intolerant to the BCM7. andra Mulcahy may well be a case in point.

Woodford ticks off the evidence against A1. For example, he says, experiments with mice found that 47 per cent of those fed A1 beta-casein developed diabetes after 250 days. None of the mice fed A2 beta-casein developed the disease.

But it's not all black-and-white, like the Mulcahy's Holsteins.

For most people, BCM7 passes through their system without further ado because it's just too big to get through their gut wall into the blood stream. Still, for about 20 per cent of people BCM7 could be a problem.

These include people who have a "leaky gut" that allows molecules called peptides to pass through. Groups who could be at risk of leaky guts include newborn babies, people with untreated celiac disease, stomach ulcers and Crohn's disease.

Public health expert Boyd Swinburn knows how heated the topic can be. He wrote a literature review of A1 and A2 beta-caseins for the New Zealand Food Safety Authority which was released in 2004. That report didn't take a hard-line stance, but didn't say the A2 coast was clear, either, though that's how the New Zealand Food Safety Authority interpreted the findings in its media hype: "all milk was safe", it spruiked, using a phrase Swinburn explicitly avoided. "The research that's there at the moment is very suggestive, but it's certainly not conclusive," says Swinburn, who now chairs Deakin University's population health program in the school of exercise and nutrition sciences. "There's good rationale for dairy farmers to consider changing their herds, but there's not empirical evidence that's strong enough for government warnings."

Likewise, Food Standards Australia New Zealand spokersperson Lydia Buchtmann says FSANZ has examined the "very limited scientific evidence available on comparative health effects of the two milks" and does not believe the available information warrants a change to the Food Standards Code.

"FSANZ has noted that further research is in progress and concluded that, while there are some interesting hypotheses being examined, it could not proceed with regulatory action on the basis of the available evidence. FSANZ has not received any applications to amend the milk provisions of the Food Standards Code to consider A1 or A2 milk," she says.

Still, Swinburn says there's now enough evidence to begin encouraging dairy farmers to switch their herds, if only as a precautionary measure. It takes about a decade to make a gradual transition to an A2-exclusive herd by breeding on A2 bulls. If the farmers keep selling regular milk with both A1 and A2 in the meantime, there's virtually nothing to lose.

"There's no added cost, no detrimental effects and very little risk, and in fact there's quite a bit to gain," Swinburn says. "In 10 years either there'll be much stronger proof of these links and the farmer will be in a better position, or if not they won't have lost anything."

Meanwhile, Swinburn says people who have a strong family history of type 1 diabetes, who are at high risk of heart disease, or who have an autistic child, may want to consider drinking A2 milk. If they can find it, that is. So far, A2 milk is available in about 1500 supermarkets-costing about twice as much as the home brands - but shoppers in Tasmania and Western Australia are out of luck as the milk is still not available there.

Woodford agrees that it's probably too early to push for changes to regulation. He says the most important thing at this stage is to make sure people are aware of all the available evidence. But that's easier said than done.

He argues that the dairy industry has downplayed the evidence amidst concerns that changing to A2 cows will create a communications and marketing nightmare and confuse consumers during the 10-year gap while the milk still contains a blend of the two beta-caseins.

"There should be clear information so that farmers and consumers can make informed decisions," Woodford says. It's a decision the Mulcahy brothers have already made

Lynnette Hoffman | May 17, 2008