I experience diarrhoea, even from lactose free milk. My doctor recommended A3 milk; is there an A3 milk, will A2 help or am I out of luck with drinking dairy?
There are different types of proteins in milk, including A1 and A2 (no A3). While more studies are needed, some research shows that people with lactose maldigestion or lactose intolerance report improvements in digestive symptoms like stomach discomfort, when they have A2 protein only milk.
Last updated 31/01/2025
Regular milk contains both A1 and A2 proteins, but there are also cows that produce milk with only the A2 protein.[1]
For people who experience gut discomfort it is recommended that they try spreading out their milk consumption (including lactose-free milk) throughout the day, have the milk with a meal,[3] or try other dairy products like yoghurt and hard cheeses, which have lower levels of lactose.[4] For some people, milk that contains only the A2 protein may be a better choice.
Several studies, both in Australia and internationally, have looked at the differences between A1 and A2 proteins and how they affect gut health. Some of these studies found that people who have trouble digesting lactose or are intolerant to lactose experienced improvements in digestive symptoms like stomach discomfort or diarrhea when they consumed milk with only the A2 protein.[2]
While more research is needed with larger groups of people and over a longer period of time, these findings are promising for those who experience discomfort after drinking regular milk.
A3 milk is a niche branded product, which is not widely accessible or available in Australia. If you wish to drink dairy, you’re best to try one of the above strategies.
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.
Was this useful?
Thank you for your feedback