Introduction
Milk’s beta-casein protein comes in A1 and A2 variants, differing by one amino acid. This affects digestion and health. A2 milk may be gentler on the stomach.
A1 and A2 milk comparison.
What is Beta-Casein?
Beta-casein is ~30% of milk protein, with A1 and A2 types:
- A2: Histidine at position 67; natural in humans, goats, and some cows.
- A1: Proline at position 67; releases BCM-7, which may cause digestive issues.
A1 vs A2 protein structure.
A1 vs A2 Milk
| Aspect | A1 Milk | A2 Milk |
|---|---|---|
| Genetic Variant | A1 beta-casein (common in Western breeds). | A2 beta-casein (some cows, goats). |
| Digestion | BCM-7 may cause inflammation. | No BCM-7; easier to digest. |
| Health Impacts | Linked to bloating, IBS-like issues (mixed evidence). | Better tolerated; may reduce allergies. |
| Availability | Most commercial milk (60-70%). | A2-labeled products. |
Health Implications
A1 Milk: BCM-7 may cause bloating or slow digestion; linked to chronic diseases (inconclusive).
A2 Milk: Studies (e.g., 2016) show less bloating, better tolerance. Ideal for sensitive stomachs.
Advice: Consult a doctor for milk issues. A2 may suit some better.
BCM-7 research overview.
Conclusion
A1 milk may cause digestive issues for some due to BCM-7; A2 milk is gentler. Choose A2 for potential health benefits.
Action: Buy A2-certified milk for better digestion.