Understanding  A1 – A2 Milk Controversy

Pashu Sandesh, 26 August 2024

On  22 August 2024, the Food Safety and Standards Authority of India (FSSAI) ordered food businesses to remove claims about A1 and A2 milk from their packaging, calling the labelling misleading. The FSSAI's decision was made in response to recent marketing efforts by dairy brands that have promoted A2 milk as being healthier and easier to digest than A1 milk. However, the scientific community is pided on the validity of these claims, and there isn't enough conclusive evidence to support the benefits of A2 milk over A1. For example, some studies suggest that A1 and A2 beta-casein may have different effects on digestion, but the research is still inconclusive and sometimes contradictory. Additionally, the impact of A1 beta-casein on human health hasn't been definitively proven. 

What’s the difference

Cow milk on average contains 87-88 per cent water and 12 to 13 per cent solids that include lactose (4.8%), fat (3.9%), protein (3.2%) and minerals (0.7%). Of this total 3.2% milk protein in cow’s milk, about 82% is casein protein and 18% is whey protein. Milk protein Casein is further composed of three main fractions -  Alpha (48%), Beta (39%) and Kappa  (13%). The distinction between A1 and A2 milk is based on the structure of beta-casein Beta casein has 13 known variants out of which two variants A1 and A2 are the most common. Beta casein has 209 amino acids. The key difference between A1 and A2 beta casein lies in the amino acid structure. A1 beta-casein has a histidine amino acid at position 67, while A2 beta-casein has proline at the same position. This slight variation affects how the protein is broken down during digestion. Beta-casomorphin-7 (BCM-7) is a peptide released in the stomach during the digestion of A1 beta-casein, which is considered harmful. On the other hand Beta-casomorphin-9 (BCM-9) peptide is released in the stomach during the digestion of A2 Beta casein, which is not considered harmful.  Production of A1 or A2 type milk by cows is determined by the genetic constitution essentially by a pair of specific genes in the combination of A2A2, A1A2 or A1A1.

The whole controversy ofA1 versus A2 started in the year 2000 when a New Zealand-based milk company called a2 Corporation patented a genetic method for identifying cattle that would produce A2 milk. It reported negative health effects of A1 milk which was attributed to Beta-casomorphin-7 (BCM7) released during digestion of A2 milk. This is why some people believe that A1 milk is less healthy than A2 milk. Some research groups propose that BCM-7 might be associated with type 1 diabetes, heart disease, infant mortality, autism, and digestive issues. However, research is short and still ongoing.

 In 2005, independent researcher Stewart Truswell published an investigation of A1 and A2 in Nature. He found that there was "no convincing or probable evidence" that the A1 beta-casein protein in cows' milk is a factor causing type 1 diabetes or heart disease. The European Food Safety Authority in 2009 did not find any relationship between BCM7 released from A1 milk in the intestines and non-communicable diseases. The controversy regarding A1 milk has almost ended globally based on several reports. Despite the lack of conclusive scientific evidence from human studies, many players are marketing milk in the name of A2 milk.

 For consumers we can say that the research is still inconclusive and contradictory, it’s essential to wait for conclusive scientific findings. The preference for A1 milk or A2 milk ultimately depends on inpidual factors such as taste preferences, dietary needs, and any specific health considerations. consumers need to make choices based on their own experiences. Ongoing research will provide more clarity on this issue in the coming time. Till that time consumers shall focus on the overall quality and nutritional value of the milk and ensure that their milk should be free from impurities, antibiotics and hormones.