A2 milk has been marketed worldwide as a gut-friendly alternative to regular cow’s milk, but new research suggests it may not be the best choice for everyone.
A clinical trial from the University of Turku in Finland found that lactose-free milk with partially broken-down proteins was just as well tolerated as A2 milk in people who can digest lactose and better tolerated in those who cannot.
The study involved 36 adults who reported milk-related gut symptoms. Participants were divided into groups based on their lactase enzyme genotype, which indicates whether they are lactose tolerant or intolerant. They rotated through test periods of drinking A2 milk, A2 milk with added lactase enzyme and lactose-free protein-hydrolyzed milk, with washout weeks in between. Researchers measured gut symptoms, inflammation markers in blood and stool, and overall tolerance.
“Of the milks investigated in our study, the lactose-free, protein-hydrolysed A1A2 milk was the best milk choice for lactose-intolerant people, and it was at least as stomach-friendly as A2 milk for those who can tolerate lactose,” said Kaisa Linderborg, PhD, professor of molecular food sciences at the University of Turku.
The findings suggest that breaking down milk proteins, combined with removing lactose, may help reduce stomach discomfort more effectively than A2 milk alone. However, the study also highlighted how complex gut symptoms can be. Some participants still reported discomfort even on milk-free weeks, suggesting multiple factors contribute beyond dairy alone. Importantly, the researchers found no differences in inflammation markers between any of the test milks or dairy-free periods.
While A2 milk may work for some, it isn’t a guaranteed solution. For people with lactose intolerance, lactose-free, protein-hydrolyzed milk may be a better bet. And for those with persistent gut issues, milk may not be the only trigger worth exploring.
This study was published in the Journal of Dairy Science and was supported by the Foundation for Nutrition Research in Helsinki, the University of Turku and Valio Ltd., a Finnish dairy company. The clinical trial was approved by the Ethics Committee of the Hospital District of Southwest Finland. One of the authors is employed by Valio Ltd.; no other conflicts of interest were reported.