biostudies-literatureChoi YSeoul National University Bundang Hospital45-53https://www.ebi.ac.uk/biostudies/studies/S-EPMC11215337biostudies-literatureUnknown29(2)β-Casein, a major protein in cow's milk, is divided into the A1 and A2 type variants. Digestion of A1 β-casein yields the peptide β-casomorphin-7 which could cause gastrointestinal (GI) discomfort but A2 milk containing only A2 β-casein might be more beneficial than A1/A2 (regular) milk. The aim of this study was to evaluate the differences in GI discomfort after ingestion of A2 milk and A1/A2 milk. A randomized, double-blind, cross-over human trial was performed with 40 subjects who experienced GI discomfort following milk consumption. For each intervention period, either A2 milk first (A2→A1/A2) or A1/A2 milk was first consumed for 2 weeks (A1/A2→A2) following a 2-week washout period. GI symptom rating scale (GSRS) scores, questionnaire for digestive symptoms, and laboratory tests includJournal of cancer preventionThe Effect of A2 Milk on Gastrointestinal Symptoms in Comparison to A1/A2 Milk: A Single-center, Randomized, Double-blind, Cross-over Study.PMC1121533706-2023-0088Kim SLee DHChoi YSong CHKim NfalseThe Effect of A2 Milk on Gastrointestinal Symptoms in Comparison to A1/A2 Milk: A Single-center, Randomized, Double-blind, Cross-over Study.β-Casein, a major protein in cow's milk, is divided into the A1 and A2 type variants. Digestion of A1 β-casein yields the peptide β-casomorphin-7 which could cause gastrointestinal (GI) discomfort but A2 milk containing only A2 β-casein might be more beneficial than A1/A2 (regular) milk. The aim of this study was to evaluate the differences in GI discomfort after ingestion of A2 milk and A1/A2 milk. A randomized, double-blind, cross-over human trial was performed with 40 subjects who experienced GI discomfort following milk consumption. For each intervention period, either A2 milk first (A2→A1/A2) or A1/A2 milk was first consumed for 2 weeks (A1/A2→A2) following a 2-week washout period. GI symptom rating scale (GSRS) scores, questionnaire for digestive symptoms, and laboratory tests includ2024-01-01T00:00:00Z2024 Jun2026-05-29T10:04:39.343Z2026-04-08T04:22:44.252ZS-EPMC112153373895758810.15430/JCP.24.007