Comparing the Gastric Transit of Commercial Milk and A2 Milk

Cow's milk contains two types of β-casein: A1 and A2. The μ-opioid peptide BCM-7 is released from A1 but not from A2. BCM-7 is associated with slower gastrointestinal transit and hence increased gastrointestinal transit times. Lactose maldigesters reported an increase in abdominal pain due to consumption of milk containing A1 beta-casein as compared to milk containing only A2 beta-casein. The hypothesis of this study is that the differential abdominal pain is due to the differential gastric transit. This is a double-blinded, randomized, controlled trial conducted to determine if the transit of A1 β-casein milk is modified in the stomach as compared to milk with only A2 β-casein.