Digestive Health

Research Team

Public Summary

Principal Investigator: Professor Nicole Roy, Department of Human Nutrition, University of Otago
Co-lead Investigator: Professor Richard Gearry, Academic Head, Department of Medicine, University of Otago, Christchurch

Collaborating Organisations: AgResearch Limited, Malaghan Institute, The University of Auckland, Plant & Food Research

In New Zealand’s large and growing food export markets in Asia we know that digestive health is a common and rising topic of concern. Healthy digestion is critical to physical health, and mental health and well-being. Approximately 30% of the population has at least one of the functional gastrointestinal disorders where “everything looks normal” and there is no detectable disease, but there are abnormal digestive processes such as altered transit and hypersensitivity. The mechanisms underpinning these health parameters are poorly defined.

Our research programme focuses on New Zealand’s food and beverage products for improving gastrointestinal function and comfort. We seek to understand the linkages between diet, gastrointestinal symptoms and disorders, metabolism, physiology and microbial populations (the microbiome) to better predict food-health gastrointestinal relationships. This will enable New Zealand’s food and beverage industry to predict the gastrointestinal health benefits of foods and ingredients and generate validated scientific evidence of these health benefits.

Our understanding of the linkages between diet, gastrointestinal symptoms, metabolism, physiology and the microbiome has been enabled by the establishment of a patient cohort, named COMFORT, and a database of information relating to the cohort. This has involved the development of a world-first validated questionnaire, the Food and Symptom Times diary which addresses a knowledge gap by enabling the food consumed on a given day to be linked with gastrointestinal symptoms. Other validated questionnaires addressing gastrointestinal symptoms, anxiety and depression symptoms and quality of life were used to cluster the participants recruited into the COMFORT cohort: healthy controls and those with constipation or diahorrea, including individuals with irritable bowel syndrome. International collaborations have enabled world-leading methods to be used for the analysis of a comprehensive suite of metabolites present in plasma, urine and breath samples obtained from the participants.

Our analyses have highlighted differences between COMFORT participants and healthy symptom-free control participants. We have seen perturbations in amino acid and lipid metabolism that are known to be associated with gastrointestinal dysfunction. Analysis of the microbiome genetic information in faecal samples has shown potential microbial mechanisms that distinguish between participants with functional gastrointestinal disorders and healthy participants. These results provide an important first step in understanding how the gastrointestinal microbiome impacts human health when gastrointestinal function is suboptimal. Our approach has enabled greater knowledge on microbiome composition and function than other studies, and we now have strong evidence that we can cluster these disorders based on metabolic and microbial biomarkers.

The research team is multidisciplinary, comprising leading New Zealand researchers who collaborate internationally and present their research to the global research community. International world-leading researchers in the gastrointestinal field recognise the Healthy Digestion programme as unique in its approach and scale, having the potential to generate significant health and industry outcomes.

The research team includes a Māori researcher affiliated to Ngāti Porou and Ngāti Raukawa, who is progressing Māori science leadership opportunities and capability in the integration of high-dimensional biological data with clinical data. We are committed to strengthening Māori researcher capacity and capability within our programme as we progress our research.

The Healthy Digestion programme works closely with New Zealand’s food and beverage industry, including Māori agribusinesses, to ensure our research is relevant for industry. This includes work with New Zealand’s industry partners to validate our approach and test food concepts. We will continue to assist Māori and non-Māori food and beverage entities, in developing and testing novel foods for improved gastrointestinal health outcomes. The programme supports the mission of the High-Value Nutrition Challenge to generate knowledge and capability that New Zealand’s food and beverage industry can utilise to develop high-value foods with validated health outcomes and thus increase export revenues.