1. Introduction
gastrointestinal symptoms, lactose intolerance [Gastric transit, abdominal pain
Lactose maldigesters report an increase in abdominal pain due to the consumption of milk containing a mixture of A1 and A2 β-casein as compared to milk containing only A2 β-casein. Gastric transit affects gastrointestinal symptoms and rapid transit has been associated with an increase in abdominal pain. We conducted a double-blinded, randomized, crossover trial in 10 lactose maldigesters. Subjects consumed each of the two types of milk: conventional milk containing 75% A1 β-casein and 25% A2 β-casein and A2 milk containing 100% A2 β-casein. Magnetic resonance images were acquired, and abdominal pain was rated and recorded at 0, 10, 30, 60 and 120 min after milk consumption. The volume of milk in the stomach was calculated using FSL software. The volume of milk in the stomach after consuming milk with 75% A1 β-casein and 25% A2 β-casein was significantly lower at 30 (Casein and whey are the two major proteins in cow’s milk. β-casein forms approximately 30% of protein in bovine milk [Several studies have shown that the consumption of milk containing A1 β-casein aggravates symptoms of lactose intolerance [Gastric transit time is associated with gastrointestinal symptoms [We hypothesized that the lower symptom scores for abdominal pain due to consumption of milk containing only A2 β-casein as compared to milk containing A1 and A2 β-casein was related to the difference in the gastric emptying time. 