Research suggests that milk containing only the A2 protein may help reduce digestive symptoms like stomach discomfort in people with lactose intolerance or lactose maldigestion. However, more studies are needed to confirm these findings.

Milk contains different types of proteins, including A1 and A2. While regular milk has both A1 and A2 proteins, some cows produce milk containing only the A2 protein.¹

Studies conducted in Australia and internationally have explored the relationship between A1 and A2 proteins and gut health. Some findings suggest that people who have trouble digesting lactose or are lactose intolerant may experience fewer digestive symptoms—such as stomach discomfort—when consuming milk with only the A2 protein.²

Although these results are encouraging, further research involving larger groups and longer-term studies is needed to confirm the benefits of A2-only milk for gut health.

If you experience digestive discomfort from regular milk, don’t worry—there are plenty of options to explore. Try spreading out your milk consumption throughout the day, pairing it with meals, or opting for other dairy products like yoghurt and hard cheeses, which naturally contain lower levels of lactose. For some people, milk containing only the A2 protein may also be worth considering.

References

1. Givens I, Aikman P, Gibson T et al. Proportions of A1, A2, B and C β-casein protein variants in retail milk in the UK. Food Chem. 2012; 139:549-552
2. Ramakrishnan M et al. Milk Containing A2 β-Casein ONLY, as a Single Meal, Causes Fewer Symptoms of Lactose Intolerance than Milk Containing A1 and A2 β-Caseins in Subjects with Lactose Maldigestion and Intolerance: A Randomized, Double-Blind, Crossover Trial. Nutrients. 2020 Dec 17;12(12):3855.
3. O’Connor L, Eaton T, Savaiano D. Improving Milk Intake in Milk-Averse Lactose Digesters and Maldigesters. JNEB. 2015;47(4):325-330.e1.
4. Szilagyi A, Ishayek I. Lactose intolerance, dairy avoidance, and treatment options. Nutrients. 2018;10:1994