A2 milk easier to digest?
Unlike normal milk, A2 milk lacks the A1 protein, also called A1 beta-casein and often associated with digestive disorders.
A new type of milk has appeared on the market in the last decade: A2 milk, which is said to be easier to digest for people who are lactose intolerant. The Rumor Detectorchecked whether it has any benefits over regular milk.
The origin of A2 milk
Cow's milk is made up of lactose, a carbohydrate, and two types of protein: whey and casein. The latter represents 80% of milk proteins and comes in several types, including beta-casein, which itself comes in several forms. The two most common are beta-casein A1 and beta-casein A2.
Ordinarily, milk sold in Canada contains these two proteins, which are associated with the genetic makeup of cows. Dairy cows with the A1A2 genetic traits produce milk containing a mixture of A1 and A2 beta-caseins, while those with the A2A2 genotype produce milk containing only A2 beta-casein.
< p>Since it is A1 that is known to be more difficult to digest, some dairy producers choose to remove cows carrying the A1A1 or even A1A2 genetic trait from their herd, keeping only those with the A2A2 genotype. And that's where what's called A2 milk comes from.
Is A2 milk easier to digest?
Studies suggest that, among people who suffer from intestinal symptoms after consuming dairy products, many are not lactose intolerant, but only beta-casein A1.
The latter would therefore be more difficult to digest than beta-casein A2 because of a difference in the sequence of amino acids that compose them. During digestion, A1 releases a peptide (BCM-7) that may cause inflammation and slow intestinal transit, leading to constipation. Sensitive people may experience stomach aches and diarrhea. Beta-casein A2 would release less of this peptide.
However, several studies that concluded that A2 milk caused less gastrointestinal discomfort were funded by a manufacturer of this new milk and carried out on very small cohorts or only in people of Asian origin who are lactose intolerant, without a control group.
Further studies on the role of beta-casein A1 and on gastrointestinal symptoms are therefore needed.
Is it healthier?
A2 milk offers the same nutrients (vitamin A, B12 and B6, calcium, vitamin D, etc.) as regular milk. It therefore has no nutritional benefits. It also tastes the same.
A systematic review published in 2019 on the effects of beta-casein A1 consumption on health and certain chronic diseases such as cardiovascular disease and diabetes, concluded that the results of clinical trials and Epidemiological studies provide “moderate” evidence for adverse digestive health effects of protein A1 compared to protein A2, and “low” or “very low” certainty for other health effects.
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As for chronic diseases, the few results on them were obtained on rats and cannot be extrapolated to humans. And the few human studies represent a small sample, says the Canadian Network for Dairy Excellence, which says the evidence linking A1 milk to chronic disease is “currently too weak to draw firm conclusions.” /p>
Verdict
It's possible that the A2 beta-casein in A2 milk is better digested than beta-casein A1, but solid proof remains to be done. Other health impacts have not been demonstrated.
