The contribution of pure exotic cattle to total milk in India producing A1 milk is around one per cent and that of crossbred cows 25.4 per cent. In India, Desi cows contribute about 20.8, buffaloes 49.2 and goats 3.5 per cent of total milk. These species predominantly carry A2 protein and the burden of consuming A1 milk in mixed milk is restricted or nearly eliminated because of heat processing before consumption. Those consuming crossbred milk for more than 50 years in India have not reported any adverse effects.
M ilk is recognized as a nearly complete food in India and globally. Milk and milk products have a special significance in human diets. Cow milk on an 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%). About 82% of the total milk protein in cow milk is casein composed of three main fractions viz., Alpha (48%), Beta (39%) and Kappa casein (13%). The Beta casein has 13 known variants out of which two variants A1 and A2 are most common. Beta casein has 209 amino acids. A2 cow milk variant at position 67 in the carbon chain carries proline whereas A1 variant at position 67 has histidine. A1 protein is the result of a natural mutation of A2 protein which occurred more than 1000 years ago.
Last year, World Milk Day was celebrated in 80 countries with 588 events. The Day started with the dairy farmers raising their glass of milk at sunrise. Milk and other dairy products were distributed to farmers, staff, families, chefs, nutritionists, doctors, students, academicians and politicians. This celebration was organized by dairy farmers, cooperatives, national dairy associations, schools, nutrition groups, dairy companies, and thousands of families and citizens.
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 New Zealand based company founded in 2000 to license intellectual properties to determine the type of protein reported negative health effects of A1 milk which was attributed to a peptide called Beta-casomorphin-7 (BCM7) released during digestion. A2 type Beta casein after digestion leads to release of Beta-casomorphin-9 which is not considered harmful.
The New Zealand based company obtained a license in 2007 to sell branded A2 milk in New Zealand, Australia, the UK and other developed countries. The European Food Safety Authority in 2009 did not find any relationship between BCM7 released from A1 milk in the intestines and the 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 have started marketing of A2 milk. The Food Safety and Standards Authority of India have not agreed to formulate food safety and quality standards for A2 milk because of lack of published information on safety. There is no evidence that any clinical trial on human beings have been conducted anywhere in the world. Rapid, reliable and least cost methods for detecting A1 protein so far have not been developed. The techniques used in the laboratories to determine A1 milk are very expensive and may cost upto ₹1000 per test. The National Academy of Agricultural Sciences (NAAS) at its workshop held on 19 May 2018 has also called for a national project to validate the claims under Indian conditions.
As of now, A1 type milk is produced by European cow breeds such as Holstein Friesian, Ayrshire and British Shorthorn. The Jersey, Guernsey and Zebu cattle of Asia and Africa produce A2 milk. Indian cow breeds and buffaloes produce A2 milk. So much so, about 90 per cent of HF cows in Germany produce A2 milk. In India, the National Bureau of Animal Genetic Resources and NDRI have also reported preponderance of A2A2 genes in Indian cows and buffaloes. The contribution of pure exotic cattle to milk in India producing A1 milk will be around one per cent and that of crossbred exotic 25.4 per cent. Desi cows contribute about 20.8, buffaloes 49.2 and goats 3.5 per cent of total milk. These species predominantly carry A2 protein and the burden of consuming A1 protein is restricted or nearly eliminated because of heat processing of milk before consumption. Most dairies process mixed milk and milk is boiled at home. Repeated heating of milk causes protein denaturation, casein-casein agglomeration and casein whey protein interactions. Thus, these biochemical phenomena are not expected to leave any adverse effects of histidine in human beings.
Those consuming crossbred milk for more than 50 years in India have not reported any adverse effects. The consumers in the North America, European Union, Asian and Latin American countries maintaining exotic cow breeds have never reported any adverse influences on their health by consuming perhaps A1 milk over centuries. There is no need for consumers to switch to milk branded as A2 on a premium price.