This is a single-site, double-blinded, randomized, controlled, cross-over study in healthy milk drinkers of 4 weeks' consumption with milk containing only A2 type beta casein (called A2 milk) versus milk containing both A1 and A2 beta casein proteins (called A1 milk) to compare the effects on gut inflammation (CRP, HB, IL-4, IgG, IgE, IgG1, IgG2a), gastrointestinal symptoms (via VAS score including Bloating, Abdominal pain, Flatulence, Break wind, Borborygmi), regional gut transit times (via 'Smart Pill') and behavioral well-being (CNAQ), and stool habits.