Dairy-sensitive individuals, this one’s for you.
Many people find that milk makes their stomach hurt. That can be because regular milk in the grocery store comes from cows that produce A1 protein.
Conventional milk like this is usually sourced from large-scale dairy farms with mixed or A1-dominant breeds.
But what makes A1 protein difficult to digest?
When A1 protein is digested, it produces a peptide called beta-casomorphin-7 (BCM-7).
When this stuff gets into your system, it can complicate things. BCM-7 can irritate the gut lining, causing inflammation or discomfort. It may also contribute to leaky gut in some sensitive individuals.
BCM-7 also interacts with opioid receptors in the gut, slowing down digestion. This may result in discomfort, particularly for those with preexisting digestive issues like irritable bowel syndrome (IBS).
Although BCM-7 is not related to lactose, its presence can exacerbate symptoms similar to lactose intolerance, such as bloating and cramping.
For some, BCM-7 may also trigger an immune response, leading to symptoms like:
- Fatigue
- Skin reactions
- Respiratory symptoms (in severe cases)
Who’s Most Affected?
- People with sensitive digestion (e.g., IBS, lactose intolerance, or leaky gut).
- Those with milk protein intolerance (different from lactose intolerance).
- Individuals prone to inflammation or immune system reactivity.
However, there’s good news: some cows’ milk only contains A2 protein. This milk comes from older breeds, like Guernsey and Jersey cows, or specially-bred herds that produce only A2 beta-casein.
A2 beta-casein doesn’t produce BCM-7 during digestion, making it easier to tolerate for many individuals. There’s substantial scientific evidence that it reduces negative symptoms in lactose-sensitive people (Ramakrishnan et al.)(though to reiterate, BCM-7 is not related to lactose). Switching to A2 milk can reduce or eliminate symptoms for people sensitive to A1 proteins.†
If you find yourself affected by regular dairy products, it might be worth switching to A2-only dairy products: milk, cheese, yogurt (and now even protein powder) all have A2 counterparts. You can usually find these at local or specialty grocery stores, or online.
When looking for these products, look specifically for an A2 label. Regular dairy products don’t distinguish between A1 and A2 proteins, and you can assume it has both unless otherwise indicated. A2 dairy is sold as a separate product and labeled as such. These brands ensure their milk comes exclusively from A2-producing cows.
Cheers to a healthier gut! 🎉🥛
Note: The information provided is for educational purposes only and is not a substitute for professional medical advice. Please consult a healthcare professional before making changes to your diet or lifestyle.
† These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease.
Relevant studies
Borș, A., Borş, S., & Floriștean, V. (2024). Health-Related Outcomes and Molecular Methods for the Characterization of A1 and A2 Cow’s Milk: Review and Update. Veterinary Sciences, 11. https://doi.org/10.3390/vetsci11040172.
Cieślińska, A., Fiedorowicz, E., Rozmus, D., Sienkiewicz-Szłapka, E., Jarmołowska, B., & Kamiński, S. (2022). Does a Little Difference Make a Big Difference? Bovine β-Casein A1 and A2 Variants and Human Health—An Update. International Journal of Molecular Sciences, 23. https://doi.org/10.3390/ijms232415637.
De Gaudry, K., Lohner, S., Schmucker, C., Kapp, P., Motschall, E., Hörrlein, S., Röger, C., & Meerpohl, J. (2019). Milk A1 β-casein and health-related outcomes in humans: a systematic review.. Nutrition reviews, 77 5, 278-306 .
He, M., Sun, J., Jiang, Z., & Yang, Y. (2017). Effects of cow’s milk beta-casein variants on symptoms of milk intolerance in Chinese adults: a multicentre, randomised controlled study. Nutrition Journal, 16. https://doi.org/10.1186/s12937-017-0275-0.https://doi.org/10.1093/nutrit/nuy063.
Milan, A., Shrestha, A., Karlström, H., Martinsson, J., Nilsson, N., Perry, J., Day, L., Barnett, M., & Cameron-Smith, D. (2019). Comparison of the impact of bovine milk β-casein variants on digestive comfort in females self-reporting dairy intolerance: a randomized controlled trial.. The American journal of clinical nutrition. https://doi.org/10.1093/ajcn/nqz279.
Ramakrishnan, M., Eaton, T., Sermet, O., & Savaiano, D. (2020). 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, 12. https://doi.org/10.3390/nu12123855.
