Research commissioned by New Zealand company A2 shows that there could be a link between heart disease and a protein in milk, according to a DowJones news report.
International dairy company Fonterra, also based in New Zealand and increasingly involved in biotechnology ventures, has reacted by disputing the study's findings.
A2 was formed two years ago after research suggesting that the milk protein beta casein A1 may cause heart disease led it to start developing milk products without the protein. The company told Dow Jones that the recent study, soon to be published in a major scientific journal, would add "real impetus" to its efforts to make its A1-free milk products widely available to consumers.
Researcher Julie Campbell, from the Center for Research in Vascular Biology at the University of Queensland, said beta casein A1 may be "critical to the likelihood" of developing heart disease.
Her study showed a significantly higher incidence of heart disease among rabbits fed a diet containing beta casein A1 compared with those fed a diet containing beta casein A2.
"The public could be offered the healthier choice of pure A2 milk which would be particularly important for the children of persons with cardiovascular disease," Campbell told the news service.
"Since the milk from Guernsey cows contains 98 per cent A2 it may be possible to change herd composition by breeding out those cows with A1," she added.
Fonterra, however, New Zealand's largest business and the world's fourth biggest dairy company by revenue, said consumers should be "cautious" about the research.
The company maintains that its analysis in the mid 1990s did not support the link between milk and heart disease and it said that the conflicting results proved the need for further studies.