Written by Narayan G Hegde
Milk has special significance in Indian mythology, culture and diets. Although considered a complete food, there are many lobbies that discourage milk consumption, alleging — without any convincing proof — that it might promote prostate and ovarian cancer, type-1 diabetes, multiple sclerosis, increased cholesterol levels, weight gain, weakening of bones, etc. In naturopathy, asthma and psoriasis patients are even advised to stop taking milk. But most people the world over — barring a minority suffering from lactose intolerance — have been consuming milk daily in various forms, without any visible problems.
In 1992, a new dimension to the debate was added, when scientists in New Zealand established a correlation between the prevalence of type-1 diabetes and the type of milk consumed. It led to the discovery of the so-called A1 and A2 types of milk. Cow milk has 87-88 per cent water and 12-13 per cent solids that includes lactose/sugar (4.8 per cent), fat (3.9 per cent), protein (3.2 per cent) and minerals (0.7 per cent). About 80 per cent of milk protein is casein, 30-35 per cent of which, in turn, comprises beta-casein. The latter can further be either A1 or A2 beta-casein. Milk containing A1 beta-casein, at the time of digestion in the small intestine, releases a bioactive peptide called beta-casomorphin-7 or BCM-7. This is an opioid, having an inhibitory effect on immune function and suspected to induce type-1 diabetes, heart disease, infant death and autism.
The above A1 type of milk is mostly produced by European cow breeds such as Holstein Friesian (HF), Ayrshire and British Shorthorn. On the other hand, Jersey and Guernsey cows in the Channel Islands, the Charolais and Limousin breeds of Southern France, and the Zebu cattle of Africa and Asia produce A2 milk, which does not release BCM-7. Many surveys, however, show the frequency of A1 and A2 milk-producing cows to more area than breed-specific. Thus, 50-65 per cent of HF cows in North America produce A1 milk. But over 90 per cent cows of the same breed in Germany produce A2 milk. Further, 98 per cent of Indian cow breeds and 100 per cent of our buffaloes produce A2 milk.
In 2000, a New Zealand company, A2 Corporation Limited, was founded to identify A2 type of cows based on genetic testing and market A2 milk. In 2003, it even petitioned Food Standards Australia New Zealand, a bi-national government agency, to print health warnings on the packages of A1 milk. Not only was this rejected, A2 Corporation was asked to even withdraw its claims on A2 milk. But that did not stop it from tying up with an Australian company, A2 Dairy Marketers, for procuring and marketing of A2 milk. In 2004, both were fined by the Australian government for making misleading claims on A2 milk.
In 2006, the book ‘Devil in the Milk’, whose author Keith Woodford linked A1 beta-casein intake to Type 1 diabetes, gave a boost to A2 milk sales in New Zealand and Australia. It led to the New Zealand Food Safety Authority commissioning the European Food Safety Authority (EFSA) to conduct a comprehensive scientific review. The EFSA’s report, in 2009, declared that no cause and effect relationship could be established between the dietary intake of BCM-7 and various diseases. However, A2 milk continued to sell at a premium, even grabbing an 8 per cent market share in Australia by 2014. Meanwhile, A2 Corporation also started marketing A2 milk in the US, UK and China.
In May last year, in a reply to my query about the current status of A1 and A2 milk, A S Truswell, a renowned nutritionist who has thoroughly reviewed the research on this subject, stated that he did not find any convincing or even probable evidence of A1 beta-casein being a causative factor for either diabetes or coronary heart disease. He further mentioned that the companies marketing A2 milk were only claiming it “tastes better” or “does not cause bloating”; they did not blame A1 milk for causing any disease.
In India, the National Bureau of Animal Genetic Resources (NBAGR), the National Dairy Research Institute and the Indian Veterinary Research Institute started research on A1 and A2 milk in 2009. But much of it involved review of research carried out in other countries. Even these only referred to research papers and books from New Zealand highlighting the harmful effects of A1 milk, while ignoring critical reports published by Truswell in 2005 and the EFSA in 2009. However, the NBAGR also screened 615 cattle representing 15 Indian breeds and found as many as 13 of these to have A2A2 genotypes. Only a small number of cattle of Malenadu Gidda and Kherigarh breeds had A1A2 genotypes.
In 2012, another NBAGR paper suggested use of bulls having A2 allele (genes) for breeding as a safety measure. It also screened 180 bulls at random from different regions. Of these bulls, only 11 per cent were reported to have A1A1 genes, while 48 per cent had A1A2 and 40 per cent A2A2 genes. Interestingly, among HF bulls, just 22 per cent had A1A1 genes, whereas 45 per cent had A1A2 and 33 per cent A2/A2 genes. Among Jersey bulls, 60 per cent had A1A2 and 37.5 per cent A2A2 genes, with only 2.5 per cent having A1A1 genes. Among crossbred bulls, a mere 1 per cent had A1A1 genes, while 50.6 per cent had A2A2 and 39 per cent A1A2 genes.
So, even if one were to assume that A1 milk is harmful, the proportion of crossbred cows in India producing this milk would be just one per cent. Also, most dairies mix the milk of cows and buffaloes during processing. In that event, the impact of A1 milk becomes negligible.
Since the EFSA’s report’s release in 2009, the controversy regarding A1 milk has almost ended globally. But in India, certain lobbies are continuing to keep this issue burning. People in Europe and the US have been consuming A1 milk for centuries, just as we in India have been drinking crossbred cow milk for over 50 years without any adverse effects being recorded. The Indian Council of Agricultural Research has commissioned a study to investigate the health safety aspects of milk from crossbred cows through animal feeding trials, the results of which are yet to come. The government should till then take a neutral stand on the issue of A1 and A2 milk. However, given that A1 milk releases BCM-7, which has a mild sedative effect, a strategy may be adopted purely as a precautionary measure.