A1/A2 Milk and β-Casomorphins: The Resurgence of Controversy

There is a growing global interest in the alternative milk product called A2 milk. A New Zealand–based company founded in 2000 advanced the hypothesis that genetic variants of β-casein may account for some milk-related health issues, such as digestibility and diabetes. For example, the hypothesis further suggests that traditional bovine milk that contains A1 β-casein may contribute to negative health effects, whereas A2 β-casein does not appear to exert these effects. The fo…