a2 Milk™ for Gut Comfort

Public Summary

Principal Investigator: Dr Matthew Barnett, AgResearch
Industry partner: University of Auckland

a2 Milk™ for Gut Comfort


This project researched the benefits of eating dairy products containing only the A2 β-casein protein on gut comfort.

The research hopes to further capture lucrative and growing dairy export markets (China and South-East Asia) where there is a high incidence of intolerance to traditional dairy products.

The project looked to demonstrate that A2 β-casein protein dairy products are well tolerated and can deliver health benefits to consumers who might be expected to experience digestive discomfort in response to traditional dairy products that contain the A1 β-casein protein.

This project was led by the a2 Milk Company Limited (a2MC). This ensured the availability of rapidly available outcomes of the research to a2MC. 

Clinical trials

The research combined expertise in clinical trials and analysis of gastrointestinal function at the Liggins Institute, The University of Auckland, and sophisticated biological sample analysis techniques from AgResearch.

In the first of two registered clinical trials (the a2 Milk™ for Gut Comfort or “aMiGo” trial) it was demonstrated that short-term subjective feelings of gut discomfort in lactose intolerant young women were improved in response to A1 β-casein-free milk (a2 Milk™) compared to conventional milk.

This was supported by the observation that breath hydrogen, a measure of lactose malabsorption, was reduced after a2 Milk™ ingestion, compared to conventional milk.

This study was unique in that it also examined the possibility of being intolerant to milk without being lactose intolerant. The results identified ‘non-lactose dairy intolerance’ which is characterised by a rapid onset set of subjective symptoms.  These symptoms were unaltered by the type of milk consumed.

Outcomes of the aMiGo clinical trial were reported at three international conferences:

  • the Food & Nutrition Conference & Expo (FNCE) in Chicago, USA (Dr Amber Milan, October 2017)
  • the Food Structures, Digestion and Health International Conference in Sydney, Australia (Professor David Cameron-Smith, October 2017)
  • the Asia-Pacific Conference on Clinical Nutrition in Adelaide, Australia (Dr Amber Milan, November 2017).

There were also twelve media reports of the study outcomes (including The New Zealand Herald, Newshub, and Newstalk ZB). The first peer-reviewed journal publication described outcomes for the aMiGo study.

The second clinical study (a randomised, double-blind, crossover trial, The role of inflammation in lactose malabsorption – a2 Milk™ for Gut Comfort Study, or Los aMiGos, investigated the response to the inclusion of A1 β-casein-free milk (a2 Milk™) and cheese in the diet, compared to consumption of conventional milk and cheese (containing a mix of A1 and A2 beta-casein).

Unlike the aMiGo study which was a single-dose study in young women, the second study included young men and women, and lasted two weeks. It aimed to determine longer term gut responses to the two dietary regimes, including perceived symptoms, inflammation, and changes in the intestinal microbiota.

This study was completed in December 2018, and analyses are currently ongoing.

Overall, this research has contributed to a strong platform for market diversification in both developed and developing markets and has played a role in significant growth in demand for a2 Milk™ products, with increased revenue for the New Zealand dairy sector in general.

The project supports the overall mission of the High-Value Nutrition National Science Challenge by generating knowledge and capability that the New Zealand food and beverage industry can utilise to develop high-value foods with validated health outcomes and thus increase export revenues.

Research team

Dr Matthew Barnett

Matthew is the lead for the research project a2 Milk for gut comfort, jointly funded by High-Value Nutrition and the a2 Milk Company.

Matthew has held a range of roles at AgResearch Ltd, including research associate and research scientist. He is involved in a range of projects investigating the importance of nutrition for health throughout life.