a2 milk is easier to digest than milk with a1 protein

This study found that A2 milk reduced some digestive symptoms (nausea, fecal urgency) and a marker of poor lactose digestion in women clinically confirmed as lactose intolerant, but the results cannot be trusted as evidence for the broader claim due to important study limitations.

• The lactose-intolerant group had only 10 participants, which limits statistical reliability
• The groups had a large ethnicity imbalance: the lactose-intolerant group was 20% Caucasian while the non-lactose dairy-intolerant group was 100% Caucasian — ethnicity affects lactase persistence and was not adjusted for in the main analysis, making symptom comparisons between groups unreliable
• Women without lactose malabsorption experienced no digestive advantage with A2 milk, and some reported more flatulence
• The company that sells A2 milk co-funded the study and contributed to the research concept
• The study enrolled only young women in New Zealand, limiting generalizability

This study found that people with confirmed lactose intolerance reported less stomach pain after drinking A2-only milk than after drinking regular (A1+A2) milk in a single, carefully controlled test. The objective measure of digestion — a breath hydrogen test — did not show a significant difference in the main group of 25 intolerant participants, and the broader positive results came from a follow-up analysis that added more participants after the study was already underway.

• Funded by A2 Milk Company, the maker of A2 milk — an interest aligned with a positive result
• The study measured digestion over 6 hours from a single glass of milk, which may not reflect everyday drinking habits
• Stomach pain improved, but bloating, gas, diarrhea, and the breath test did not show significant improvement in the main group
• The broader results showing improvement in both symptoms and breath hydrogen were from a post hoc expanded group not part of the original plan, and do not hold up after correcting for multiple tests
• The study enrolled 25, and expanded to 33 people, so results need confirmation in larger independent studies