Digestive Health

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

Public Summary

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, mental health, and wellbeing.  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.

The Digestive Health Priority Research Programme focuses on New Zealand 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 relationships.  This scientific evidence will enable the New Zealand food and beverage industry to market the gastrointestinal health benefits of foods and ingredients in export markets.

Our understanding of the linkages between diet, gastrointestinal symptoms, metabolism, physiology, and the microbiome has been enabled by the establishment of a participant cohort, named COMFORT, and a database of information relating to the cohort.  A world-first validated questionnaire, the Food and Symptom Times diary, was developed.  This questionnaire addresses a knowledge gap by enabling the food consumed by someone 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 into a healthy control group or a group of individuals with constipation or diarrhoea – including irritable bowel syndrome.  International collaborations have enabled world-leading methods to analyse a comprehensive suite of metabolites present in plasma, urine, and breath samples obtained from the participants.

Our analyses have highlighted differences between participants with gastrointestinal symptoms 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 stool samples has shown potential microbial mechanisms that distinguish between participants with functional gastrointestinal disorders and healthy participants.  These results provide an important step in understanding how the microbiome impacts human health when the gastrointestinal function is suboptimal.  Our approach has enabled greater knowledge of microbiome composition and function than other studies, and we now have strong evidence that we can cluster these gastrointestinal disorders based on metabolic and microbial biomarkers.

We continue to work closely with the New Zealand food and beverage industry to ensure our research is relevant to the industry, including evaluating food products and ingredients in clinical settings relevant to digestive health.  We are developing new projects with Māori and non-Māori food and beverage entities for evaluating food-rongoā for improved digestive health outcomes.  We have continued strengthening Māori researcher capacity and capability.  We support the mission of the High-Value Nutrition National Science Challenge to generate 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


Professor Nicole Roy

Dr Nicole Roy is a Professor in the Department of Human Nutrition at the University of Otago. She is based in Palmerston North and leads the Digestive Health Priority Research Programme for the High-Value Nutrition National Science Challenge.

Nicole completed her PhD in Canada and the United States and post-doctoral studies in Scotland. Here she focused on how nutrition and food components can modify inter-organ nutrient partitioning and communication using tracer kinetics, animal models and in vitro models.

Nicole is also an Adjunct Professor at the Riddet Institute.