Science is the new battleground in the milk wars and A2 Milk is strengthening its arsenal.
The fast-growing New Zealand company has armed itself with the first human scientific study that reveals its controversial namesake protein can be easier to digest than regular milk.
The European Journal of Clinical Nutrition has published the research from Curtin University in Perth. A2 Milk funded the study, which showed people who consumed the A2 protein were less susceptible to bloating and other stomach aches than those who consumed the A1 protein.
Regular cows milk contains a blend of the A1 and A2 beta casein proteins. But it is A2 that marketers have seized, despite the science around the protein being until now inconclusive.
Prominent Australian nutritionist Dr Joanna McMillan said the Curtin study was the first step in clarifying some of the milk claims in the health market. But she said more research was needed.
"This study has recorded the symptoms. The next phase of the study is to understand what is happening at gut level," Dr McMillan said.
The Curtin study involved 41 men and women. After a two week "dairy wash out" in which they drank rice instead of cows' milk, they consumed 750ml a day of either A1 or A2 milk. After two weeks they had another "was out", then swapped milks, which they drank for another two weeks.
The blind trial showed the A1 protein milk had a 61 per cent higher bloating score and 38 per cent higher abdominal pain score compared with A2 as well as a softer stool consistency.
It has followed two animal studies that have investigated the effects of A1 versus A2.
Associate professor Sebely Pal of Curtin University said those animal studies had shown that the A1 protein released a peptide called BCM-7, which has been linked to gut inflammation. She said the A2 protein didn't release this peptide.
Associate professor Pal said although A2 funded the study, the company had no input into its design or influence in the results.
"It's irrelevant where the funding comes from. As researchers we are very objective when we carry out these studies," associate professor Pal said.
"It has gone through a rigorous peer reviews. International researchers have torn the data apart so when it's published it's of the highest quality.
''This pilot study shows that A2 Milk, because it doesn't have any A1 beta-casein, has different gastrointestinal effects. The milk that contained A1 beta-casein led to statistically significant differences in stool consistency, with the A1 being looser. This effect was particularly strong for women.''
''We knew there were differences in animals consuming A2 Milk without any A1 beta-casein, but this is now supported by our new human study,'' she said.
A2 Milk Australia chief executive Peter Nathan said the trials confirmed what the company's customers had been saying about the product.
"Science will always catch up with human experience," Mr Nathan said.
Geoffrey Babidge, managing director and CEO of The a2 Milk Company, said: ''The reported outcomes are significant in providing further insight into the digestive benefits that thousands of a2TM Milk consumers experience every day.
''It further underpins our belief that more consumers can enjoy the benefits of natural dairy milk without having to resort to modified milk and non-dairy alternatives.''
- Sydney Morning Herald