You may have seen a2 milk in your grocery store. This pricey designer milk comes with some big claims. Let’s explore the science behind the hype.

IN THIS ARTICLE YOU’LL DISCOVER

• What A2 milk is and what makes it different from regular milk
• The health claims made about A2 milk
• Whether the science behind those claims holds up

This week’s show was suggested by Nutrition Diva listener Leslie Ghiringhelli, who wrote:

“I was recently at my local health food store and overheard a salesperson from a company that sells A2 milk touting its superiority over regular milk. She was saying that the protein that’s in regular milk (but not A2 milk) causes everything from diabetes to autism to autoimmune disease. As an RN and science-minded person, I was immediately skeptical. Could you do a show on this topic?”

I have to applaud Leslie’s skepticism. A2 milk is about twice the price of regular milk. But is it really better for us? Perhaps the more pressing question is whether there’s any truth the claim that regular milk is linked to these scary diseases.

What’s the Difference between A1 and A2 milk?

A1 and A2 are both types of casein, which is one of the major kinds of protein in milk. Proteins are made up of individual amino acids strung together into long strings. There are only a couple dozen different amino acids, but they can be combined in different sequences to form thousands of different proteins. It’s sort of like the way the twelve tones in a musical scale can be combined into an infinite number of melodies.

The only difference between the A1 and A2 milk protein is that the 67th amino acid in the chain is different. Your body digests casein (and all proteins) by snipping these long strings of amino acids into shorter segments called peptides, some of which may have biological activity. Collagen and insulin are both peptides, for example.

The only difference between the A1 and A2 milk protein is that the 67th amino acid in the chain is different.

The slight difference in the amino acid sequence of A1 and A2 casein results in the creation of slightly different peptides when these milk proteins are digested. When we digest the A1 form of casein, it produces a peptide called BCM-7. This peptide is not produced in the digestion of A2 casein.

But so what? Does the BCM-7 peptide do any harm?

Back in the 1990s, concerns were raised that the BCM-7 peptide might be linked to conditions ranging from autism and schizophrenia to type 1 diabetes and heart disease. If that were true, it would suggest that drinking milk containing A1 casein—which is to say, most milk—could contribute to these conditions. Sensing an opportunity, the a2 Milk company developed and patented a genetic test which allowed them to identify cows that produce only A2 casein in their milk. They began selling A2 milk at a premium price.

But A2 milk turned out to be a solution to a problem that didn’t exist. Subsequent reviews by independent researchers found “no convincing or probable evidence” that the A1 casein protein in cow’s milk is a factor in type 1 diabetes or heart disease. The link between A1 milk and autism or schizophrenia was characterized as “speculative” and “unsubstantial.”

The link between A1 milk and autism or schizophrenia was characterized as ‘speculative’ and ‘unsubstantial.’

The European Food Safety Authority reviewed the evidence on the possible harmful effects of BCM-7 in 2005 and determined that it wasn’t even enough to merit a formal risk assessment study.

In response to these findings, the A2 Milk Company pivoted and refocused their marketing on claims that A2 milk might help some people avoid digestive discomfort. (Although, judging by Leslie’s experience in her local health food store, there are still some A2 marketing reps in the field who haven’t gotten the memo.)

Is A2 milk really more digestible or easier on the gut? Well, there are quite a few rats who think so. But rodent studies are not the same as human studies. One of the few studies involving human subjectsrecruited 45 Chinese people, all of whom said that drinking milk caused them digestive symptoms. (About half of them turned out to be lactose intolerant.) In this study, the subjects reported fewer digestive symptoms after drinking A2 milk than after drinking conventional milk.

The Bottom Line on A2 Milk

Other than the price, there’s no harm in drinking A2 milk. But there’s also little evidence to suggest that A1 milk or the BCM-7 peptide present a threat. If drinking milk doesn’t cause you any symptoms, I don’t think there’s much to gain from paying twice as much for A2 milk.  

A2 milk has the same amount of lactose as conventional milk.

If you are lactose intolerant, you’re probably better off with a lactose-free or lactose-reduced milk. A2 milk has the same amount of lactose as conventional milk. You could also try taking an over-the-counter lactase supplement when you consume dairy. Of course, simply avoiding dairy products is also an option.

If you really want to drink milk, and lactose-free milk doesn’t relieve your symptoms, you could try A2 milk and see whether it makes enough of a difference to justify the extra expense. Obviously, that’s a judgment call.

Thanks again, Leslie, for giving me the opportunity to shed some light on this subject. It’s a good reminder that folks selling expensive solutions to problems that may or may not exist are probably not the most reliable sources of information about those products.