A2 milk stands out from the herd

There is a case that a pro­tein found in some milk may do harm, writes Lyn­nette Hoff­man

The Weekend Australian - Travel - - Health -

THREE years ago Vic­to­rian dairy farm­ers Wayne, Peter and David 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. Peter’s young daugh­ter, Alexandra, 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, Alexandra could drink A2 milk with­out get­ting sick.

Our ex­pe­ri­ence with Alexandra not only con­vinced us to con­vert to A2 cows, we be­lieve the whole Aus­tralian dairy in­dus­try will even­tu­ally move that way too,’’ Peter 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 Keith Wood­ford, pro­fes­sor of farm man­age­ment and agribusi­ness at Lin­coln Univer­sity in New Zealand, and the au­thor of a book on the sub­ject, .

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

Devil in the Milk

‘‘ 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. Alexandra 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 be­ta­ca­sein 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 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 be­ta­ca­seins.

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.

Pic­ture: Stu­art McEvoy

Spe­cial cows: Peter Mulcahy and daugh­ter Alexandra with their A2 cows

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