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The origin of A2 milk
Cow’s milk consists of lactose, a carbohydratesand two types of protein: whey and casein. The latter accounts for 80% of milk proteins and comes in several types, including beta-casein, which itself comes in several forms. The two most common types are A1 beta-casein and A2 beta-casein.
Milk sold in Canada usually contains these two proteins, which are linked to the genetic makeup of cows. Dairy cows with the A1A2 genotype produce milk that contains a mixture of A1 and A2 beta-caseins, while cows with the A2A2 genotype produce milk that contains only A2 beta-casein.
Because A1 is the most difficult to digest, some dairy producers choose to remove cows carrying the A1A1 or even A1A2 genotype from their herd, keeping only the A2A2 genotype. Hence the so-called A2 milk.
Is A2 milk easier to digest? ?
Studies show that among people who experience gastrointestinal symptoms after consuming dairy products, many do not have lactose intolerance, but only A1 beta-casein.
the last It will be more difficult to digest of A2 beta-casein due to the difference in the chain of amino acids that make it up. During digestion, A1 releases a peptide (BCM-7) that can It causes inflammation and slows down intestinal transitWhich leads to constipation. Sensitive people may experience stomach pain and diarrhea. there A2 beta-casein releases less of this peptide.
However, many of the studies concluding that A2 milk causes less gastrointestinal discomfort were funded by and carried out by the manufacturer of this new milk. Very small groups Or only in people of Asian descent Lactose intolerantwithout a control group.
Therefore more studies are needed on the role of beta-casein A1 and gastrointestinal symptoms.
Is it better for health ?
A2 milk offers the same nutrients (vitamin A, B12, B6, calcium, vitamin D, etc.) as regular milk. So it has no nutritional benefits. It also tastes the same.
a Systematic review published in 2019 and addresses the effects of A1 beta-casein consumption on health and certain chronic diseases such as cardiovascular disease and diabetes, concluding that results from clinical trials and epidemiological studies provide “moderate” evidence of negative effects on GI health of A1 protein compared to A2 protein, and certainty” low” or “very low” for other health effects.
As for chronic diseases, few results have been obtained in mice and cannot be extrapolated to humans. The few studies in humans represent a small sample, says the Canadian Network for Dairy Excellence, which notes that evidence linking A1 milk to chronic disease is “Currently too weak to draw firm conclusions“.
to rule
It is possible that the A2 beta-casein in A2 milk is better digested than the A1 beta-casein, but solid evidence remains to be done. Other health effects have not been proven.
Photo: Santeri Viinamäki/Wikipedia Commons/ CC 4.0
