on Fibre & Food MonitoringA symposium examining two topical aspects of human nutrition and health: the role of dietary fibre in preventing and treating non-communicable diseases; and the importance of knowing what New Zealanders eat to inform health research and policy.

11–12 February, 2019Hutton Theatre, Otago Museum Dunedin

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on Fibre & Food Monitoring

Programme

1:00 Mihi whakatau Mark Brunton University of Otago

Opening remarks Robert Beaglehole University of Auckland

Session Chair: Paul Moughan (Riddet Institute)

1:30 The origins of the dietary fibre hypothesis John Cummings University of Dundee

2:10 Fibre to maintain health Andrew Reynolds University of Otago

2:40 Carbohydrates: heroes or villains in Jim Mann diabetes management? University of Otago

3:10 Afternoon tea

Session Chair: Paul Moughan (Riddet Institute)

3:40 Fibre in the food we eat Lisa Te Morenga Victoria University of Wellington

4:10 Fibre and the gut microbiome Michael Schultz University of Otago

4:40 Fibre and the physiology of the large bowel John Cummings University of Dundee

5:30 Drinks and canapés – Hutton Theatre

6:30 Symposium dinner – Beautiful Science Gallery

Guest speaker Stewart Truswell University of Sydney

FOCUS ON FIBRE

MONDAY 11 FEBRUARY

11:00 Morning tea

Session Chair: Lisa Houghton (University of Otago)

11:30 Use of biomarkers to assess the nutritional status Rosalind Gibson of populations: challenges and possible solutions University of Otago

12:00 Population food choices – traditional and emerging Kathryn Bradbury methods to assess diet in prospective cohort studies University of Auckland

12:30 Measuring population sodium intake: Rachael McLean a WHO priority but how should we do it? University of Otago

1:00 Lunch

2:00 Fibre Workshop John Cummings (chair) University of Dundee

Food Monitoring Workshop Sally Mackay (chair) University of Auckland

4:30 Close

FOCUS ON FOOD MONITORING

WORKSHOPS

Session Chair: Jenny Reid (Ministry for Primary Industries)

9:00 Dietary Surveys in NZ: history and scope Winsome Parnell University of Otago

9:45 How do we know what Aussies eat and what’s in it? Tracy Hambridge Food and nutrition monitoring in Australia Food Standards Australia New Zealand

10:30 Dishing it up: highlights of research using NZ Claire Smith National Nutrition Survey data University of Otago

TUESDAY 12 FEBRUARY

#fibreandfood #fibreandfood

EDGAR DIABETES &OBESITY RESEARCHA UNIVERSITY OF OTAGO RESEARCH CENTRE

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Speaker Abstracts

The role of fibre in human nutrition began to be investigated towards the end of the 19th century when the first human feeding studies were done by Rubner in Germany. However, between 1966 and 1972, Denis Burkitt, a surgeon who had recently returned from Africa, brought together ideas from a range of disciplines together with observations from his own experience to propose a radical view of the role of fibre in human health.

Burkitt came late to the fibre story but built on the work of three physicians (Peter Cleave, G. D. Campbell and Hugh Trowell), a surgeon (Neil Painter) and a biochemist (Alec Walker) to propose that diets low in fibre increase the risk of coronary heart disease, obesity, diabetes, dental caries, various vascular disorders and large bowel conditions such as cancer, appendicitis and diverticulosis. Simply grouping these diseases together as having a common cause was groundbreaking.

Proposing fibre as the key stimulated much research but also controversy. Credit for the dietary fibre hypothesis is given largely to Burkitt who became known as the ‘Fibre Man’.

The origins of the dietary fibre hypothesis

John CummingsUniversity of Dundee School of Medicine, Dundee, Scotland, UK

Carbohydrates: heroes or villains in diabetes management?Low carbohydrate diets have long been in the mainstay of the nutritional management of people with diabetes. Benefits of high fibre diets were first reported from uncontrolled studies in the United States in the mid 1970s, following Trowell’s earlier suggestion that dietary fibre was protective against type 2 diabetes. Soon thereafter short term controlled studies showed that extracted fibre (initially guar gum) could reduce urinary and blood glucose levels and controlled studies of six weeks or longer that diets high in fibre-rich carbohydrate could improve overall glycaemic control and improve the lipid profile. Benefits were particularly striking when much of the dietary fibre was derived from pulses. More recent suggestions of benefits associated with a low carbohydrate diet have diminished the initial widespread enthusiasm for high fibre diets. However such benefits have only been demonstrated in trials of short duration and when nature of carbohydrate has not been considered. Systematic review and meta-analyses of existing trials confirm the benefit of high fibre diets in terms of glycaemic control and cardiovascular risk with observational data suggesting that risk reduction translates into improved clinical outcomes. While a wide range of total carbohydrate intakes appears to be acceptable for people with diabetes, there is no evidence for long term benefits of very low carbohydrate diets which cannot provide recommended levels of dietary fibre shown to be of benefit in terms of glycaemic control and reducing the risk of a range of non–communicable diseases.

Jim Mann Department of Medicine, University of Otago

Fibre and the physiology of the large bowelThe dietary fibre hypothesis is so wide ranging (and includes the key diseases of most “Western” countries) that it has invited controversy and disbelief. In 1972 we started looking at the effects in the large bowel and were able to show that fibre was the key element in the diet to affect bowel habit, and that it was almost entirely degraded by the resident microflora in a series of reactions known as fermentation. This process is key to the health of the colon and yields principally short chain fatty acids (SCFA), the gases hydrogen, carbon dioxide and methane and stimulates the growth of the microflora (biomass). SCFA are rapidly absorbed and so contribute to the body’s overall energy balance. We showed that acetate reached the peripheral circulation, did not stimulate insulin release and was an essential substrate for some tissues. Propionate was taken up by the liver and butyrate by the colonic epithelium. Butyrate especially may be important in the prevention of large bowel cancer. Thus an entirely new concept in human digestion was described, which required the colon and its bacteria and which both supplemented and contrasted with small bowel digestion and absorption.

John CummingsUniversity of Dundee School of Medicine, Dundee, Scotland, UK

Fibre to maintain healthCarbohydrates are perhaps the most contentious nutrient, with a wide range of opinions available on their intake and relationship with health or ill health. This talk considers carbohydrate intake over the life course, and its role in non–communicable disease incidence and mortality. Prevalent diseases in New Zealand such as heart disease, stroke, type 2 diabetes, and several cancer types will be discussed, as will the nature of the relationship between carbohydrate intake and such outcomes.

Andrew Reynolds Department of Medicine, University of Otago

Fibre and the gut microbiomeWe are what our bacteria eat - The intestinal microbiome contains around 1014 organisms, but the concentration and composition varies throughout the gastrointestinal tract. It can also be seen as an ecosystem, with metabolites produced by some bacteria used as substrates by other bacteria. Each individual person has a unique microbiome and there is wide variation within the population depending on a number of external and internal factors such as geographical location, nutrition, immune system. Diet, besides antibiotic treatment, is the environmental factor with the greatest effect on the microbiome. Some individual foods and nutrients have been studied in greater detail than others, with the best studied being dietary fibre. Much of the beneficial effect of fibre however is mediated by the microbiome and the metabolites produced, mainly short chain fatty acids (SCFA). However, not all fibres are the same and some bacteria are more selective in the substrates which they ferment. It has been shown in animal models that just altering the fibre content in the diet has a dramatic effect of the composition of the microbiome. Hence diet therapy is often sought by patients, but evidence of therapeutic effects mediated by dietary modification of the microbiome is sparse. The best evidence is probably available for the low FODMAP diet in the treatment of Irritable Bowel Syndrome, and also an inverse relationship has been demonstrated between fibre intake, especially cereal fibre, and colorectal cancer.

Michael Schultz Department of Medicine, University of Otago

Dietary Surveys in NZ: history and scope Dietary Surveys have been carried out in NZ since 1926. Initially surveys representing ‘most NZ’ers’ or sub-populations were funded by universities and various grant funding agencies. A University of Otago report to WHO in 1962 emphasised over–nutrition, nutrition issues among Māori, concern about breast feeding rates and dental caries.

Surveys which have included detailed dietary data and nationally representative samples have been conducted in 1989, 1997, 2002 and 2008/09 - the latter three government–funded and allowing some monitoring of the nation’s nutritional status.

Key to effective monitoring of nutritional status are the following: establishing desired outcome variables prior to survey planning and funding; effective multicultural and multidisciplinary team work across all aspects of survey planning, and execution; input from the data providers into data analysis and interpretation.

An understanding of food production and processing is critical in planning data collection and in analysis and interpretation of the findings. The monitoring of nutritional status requires careful integration of food and nutrient intake data, along with anthropometric, biochemical and clinical data.

Winsome ParnellDepartment of Human Nutrition, University of Otago

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Population food choices – traditional and emerging methods to assess diet in prospective cohort studiesThe body of nutritional epidemiology literature has – almost exclusively – relied on pen and paper food frequency questionnaires to rank participants by dietary intakes and estimate the risk of disease for those with high compared to low intakes of food groups and nutrients. New web-based methods are emerging that can be used to assess diet. Intake24, myfood24, and ASA24 are web-based 24-hour dietary recalls which largely mimic an interviewer-led 24-hour recall. The Oxford WebQ is a different 24-hour dietary assessment method that has been completed at least once by over 200,000 participants in the UK Biobank. These methods have some advantages, but also some limitations, notably that participants need to complete them multiple times in order to capture usual dietary intakes. New Zealand has a wealth of routinely collected health information, but there is no dietary data linked with this other health information. In addition, we have not had a nutrition survey for a decade. What method(s) could be used to assess diets of large numbers of New Zealanders? Could this dietary information be linked to routinely collected health information?

Kathryn BradburyNational Institute for Health Innovation, University of Auckland

Dishing it up: highlights of research using national nutrition survey dataNational nutrition survey data in New Zealand has been used for many applications including identifying those at risk of nutrient deficiencies, tracking trends in food and nutrient intakes, informing public health policy relating to fortification practices and dietary guidelines, examining risks in the food supply and providing evidence for new research. In New Zealand, 24 hr recalls have been used to collect detailed information on the types of foods people eat. A 24 hr recall is only a small snippet of one person’s life however, combined with thousands of others, provides powerful insights into the eating-habits of a nation. In this talk Claire will use 24 slides to dish-up examples of research and applications of the 1997 National Nutrition Survey, the 2002 Children’s Nutrition Survey and the 2008/09 Adult Nutrition Survey.

Claire Smith Department of Women’s and Children’s Health, University of Otago

Measuring population sodium intake: a WHO priority but how should we do it?The WHO Global action plan for the prevention and control of non-communication diseases has identified nine voluntary global targets for action by 2025, including a reduction in population dietary sodium intake by 30%. This is based on extensive evidence that high dietary sodium intake is associated with raised blood pressure and increased risk of cardiovascular disease. Monitoring of adherence with the WHO target requires accurate measurement of population sodium intake, and accurate measurement of usual intake in individuals is essential for epidemiological studies investigating associations between sodium intake and health outcomes. Although 24 hour urine collection is widely regarded as the ‘gold standard’ measure, it can be burdensome for participants and so other methods are often used. This presentation explores advantages and disadvantages of different methods of measurement, and discusses implications for monitoring and policy.

Rachael McLeanDepartment of Preventive and Social Medicine, University of Otago

How do we know what Aussies eat and what’s in it? Food and nutrition monitoring in AustraliaThis talk will provide a brief overview of the food and nutrition monitoring policies and systems in Australia. It will illustrate how concentration data for nutrients and other chemicals in foods are collected, and will include a summary of Australian nutrition surveys and the types of data available from these. Information on how all of these data sets are used in food chemical risk analysis domestically, and in the international space, will be outlined.

Tracy Hambridge Food Standards Australia New Zealand, Canberra, Australia

Population-level nutritional biomarkers are used in public health for screening, surveillance, and monitoring and evaluating interventions. They can be classified into biomarkers of exposure (dietary intake), status (tissue content) and function. The selection of nutritional biomarkers is dependent on several important attributes impacting on their performance and interpretation, as well as issues related to implementation, the context of use, and capacity/resource needs. This presentation will review factors that must be considered when selecting nutritional biomarkers, and highlight some of the challenges facing their interpretation and use, citing examples from micronutrient case studies. Finally, approaches that can be used to overcome some of these challenges will be discussed.

Use of biomarkers to assess the nutritional status of populations: challenges and possible solutions

Rosalind GibsonDepartment of Human Nutrition, University of Otago

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Chairs and speakers

Kathryn BradburyKathryn Bradbury was awarded a PhD in Human Nutrition from the University of Otago in 2012, for her project measuring blood folate status in adults from the participants of the 2008/09 New Zealand Adult Nutrition Survey. Following her PhD, Kathryn spent 5 years at the Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, where she held the Girdlers’ HRC fellowship. She worked with paper-based food frequency questionnaires to investigate relationships between diet and disease in large population studies – the European Prospective Investigation into Cancer and Nutrition (EPIC), and the Million Women Study. During her time in Oxford, Kathryn was also responsible for the Oxford WebQ – a web-based 24-hour dietary assessment tool used to collect dietary information from over 200,000 participants in UK Biobank. Kathryn has returned to New Zealand and has been awarded the Sir Charles Hercus HRC fellowship.

John H CummingsJohn H Cummings is unquestionably one of the most distinguished gastroenterologists in the United Kingdom. His most important discovery was the anaerobic metabolism of carbohydrate in the large bowel, one of the major discoveries in this field in the last century. He was Professor of experimental gastroenterology at the University of Dundee, has previously been head of the Gastroenterology group at the MRC Dunn Clinical Nutrition Centre in Cambridge, as well a consultant gastroenterologist at Addenbrooke’s Hospital in Cambridge. He is an advisor to the World Health Organisation and has been a member and chair of innumerable relevant government advisory bodies in the United Kingdom.

Rosalind GibsonRosalind Gibson is an Emeritus professor in the Department of Human Nutrition, University of Otago. She has an MS PH (Nutrition) from the School of Public Health, University of California, Los Angeles, USA and a PhD in Nutrition from the University of London, UK. She has had a life-long interest in international nutrition, initially working in the Ethio-Swedish Children’s Nutrition Unit in Ethiopia for three years, and subsequently in collaborative research studies on micronutrients in Papua New Guinea, Guatemala, Ghana, Malawi, Zambia, and Ethiopia as well as Thailand, Mongolia and more recently Cambodia, NE Brazil, and Indonesia. Professor Gibson is a member of the International Zinc Nutrition Collaborative Group (IZiNCG), a fellow of the American Society of Nutrition, and a fellow of the Royal Society of New Zealand. She has served on several expert committees for WHO, FAO, WFP, UNICEF, and the US National Academies of Sciences.

Robert Beaglehole Robert Beaglehole trained in medicine, cardiology, epidemiology and public health in New Zealand, England and the USA before becoming a public health physician. He was Professor of Community Health at the University of Auckland, New Zealand (1988-1999). In 2000 he joined the staff of the World Health Organization and was engaged in a variety of public health roles. Between 2004 and 2007 he directed the Department of Chronic Disease and Health Promotion. In 2007 he returned to New Zealand. He is now an independent global public health practitioner with a focus on the prevention and control of noncommunicable diseases (NCDs) in New Zealand, the Pacific and globally. He founded ASH in 1982 and now chairs the organisation which actively supports the Smokefree Aotearoa 2025 Goal. He is Professor Emeritus of the University of Auckland and chairs the Lancet NCD Action Group.

Tracy Hambridge Tracy Hambridge holds a Bachelor of Applied Science in Nutrition from the University of Canberra, a Masters in Nutrition and Dietetics from Deakin University, Melbourne, and has worked at Food Standards Australia New Zealand (FSANZ) for over 18 years. She currently holds the position of Principal Specialist – Dietary Exposure Assessment. Her primary role is conducting dietary exposure assessments for a range of food chemicals (e.g. food additives, contaminants, agricultural and veterinary chemicals and nutrients), including for food standards development and food analytical surveys. Tracy has a detailed knowledge of national dietary surveys, and has worked in the nutrition risk assessment and risk management areas of FSANZ, in addition to assisting with the implementation of a usual nutrient intake methodology at the Australian Bureau of Statistics, for the most recent Australian national nutrition survey. Tracy has participated as an invited expert on exposure assessment for the Joint FAO/WHO Expert Committee on Food Additives (JECFA).

Sally Mackay Sally Mackay is a Registered Nutritionist who recently completed a PhD at the University of Auckland on the INFORMAS (International Network for Food and Obesity/non-communicable diseases, Research, Monitoring and Action Support) methodology of monitoring food prices over time. She is working as a research fellow monitoring the healthiness of the packaged food supply and is interested in reformulation of packaged foods, food affordability, monitoring food companies commitments to health and monitoring the wider food environment. She worked with the New Zealand INFORMAS team on assessing Government’s level of implementation of policies for improving food environments, and a report of a comprehensive assessment of food environments. Her previous work as a public health nutritionist for a wide range of organisations included working for the Ministry of Health for the 2008/09 Adult Nutrition Survey.

Lisa Houghton Lisa Houghton is the Head of Department of Human Nutrition, University of Otago and Director of the World Health Organisation Collaborating Centre for Human Nutrition in the Western Pacific Region. She completed her undergraduate and MSc training at the University of Guelph, Canada, her dietetic training at McMaster Health Sciences, and her PhD at the University of Toronto. Lisa’s research is focused on the assessment and health consequences of micronutrient deficiencies in at risk population groups, with particular expertise in maternal and young child undernutrition.

Rachael McLean Rachael McLean is a Public Health Physician and Senior Lecturer in Public Health and Epidemiology in the Department of Preventive & Social Medicine, University of Otago. She has a particular research interest in assessment of sodium intake in individuals and populations, as well as policy and strategies for dietary sodium reduction. She is an active member of several international research collaborations including the Science of Salt and the TRUE Consortium; a consortium of health and scientific organizations formed to set minimum standards for the conduct of clinical and epidemiological research on dietary sodium. She has acted as an adviser to the World Health Organization, and is currently on the Expert Working Group for Sodium, a Trans-Tasman appointed panel advising the Australian and New Zealand governments on Nutrient Reference Values.

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Lisa Te Morenga Lisa Te Morenga (Ngapuhi, Ngāti Whātua, Te Rarawa) is a Senior Lecturer in Māori Health and Nutrition in the School of Health at Victoria University of Wellington. She specialises in the role of diet in the treatment and prevention of obesity, diabetes and cardiovascular disease, with a particular interest in nutrition and hauora (Māori health). She completed a doctorate in human nutrition at the University of Otago in 2010. She was subsequently a Senior Research Fellow and Associate Dean Māori for the University of Otago Division of Sciences, and has received funding from the Health Research Council, the Riddet Institute Centre of Research Excellence, and Healthier Lives National Science Challenge. Dr Te Morenga combines her research with community and international outreach, and has worked with organisations including the World Health Organisation, Toi Tangata, Ngāti Porou Hauora, the National Heart Foundation, and the Royal Society Te Apārangi.

Winsome Parnell Winsome Parnell’s academic career spans more than 45 years, and has included major research interests in children’s nutrition issues, both in NZ and in the Pacific region. Throughout her career she has been involved in Nutrition Surveys of NZ, and she initiated the New Zealand Food Composition Database in conjunction with the Government agency DSIR (now held by Plant and Food research). She has contributed to National Nutrition Surveys, with a particular interest in the evolving 24 diet recall methodology, and latterly in the development of an index to measure Household Food Insecurity in New Zealand. Winsome’s National Nutrition Survey roles have also included analysis of the LINZ 89 survey data, membership of Ministry of Health Technical Advisory Committees and lead roles in the University of Otago provider teams for these national surveys for quality control of dietary data collection, data analysis, and writing of survey reports in collaboration with the Ministry of Health.

Jenny ReidJenny Reid (MDiet; MPH; MPA) manages a team at the Ministry for Primary Industries who are responsible for the development, maintenance and enhancement of market access across South East Asia. She ensures the necessary government to government technical relationships are developed and enhanced, and is accountable for negotiating and promulgating the export requirements (including certification) for New Zealand’s exports of primary products and food to support market access. Jenny has worked for the New Zealand government in the area of food regulations and in international policy development, having previously managed all of the food safety scientists within MPI. She is very active in the area of international standard development where she leads the New Zealand delegation to both the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) and the Codex Committee on Food Labelling (CCFL), where New Zealand is leading key work projects in both these committees.

Michael Schultz Michael Schultz studied in Erlangen-Nuremberg, Germany and trained in Manchester, London and Regensburg, Germany. He went to Chapel Hill, NC at the University of North Carolina for his postdoctoral fellowship to research the effect of probiotics in Inflammatory Bowel Disease under the mentorship of Professor Balfour Sartor.

He joined the Department of Medicine at the University of Otago in 2005 taking up a joint clinical position as a Senior Lecturer, and Gastroenterologist with the Southern District Health Board. He was appointed Head of the Department of Medicine in 2016 and was President of the New Zealand Society of Gastroenterology from 2016 to 2018. He is also the director of the GutHealthNetwork (www.guthealthnetwork.com) and Medical Advisor to Crohn’s and Colitis NZ. He was promoted to Professor in 2019.

His research expertise is focused on clinical and basic scientific aspects of Inflammatory Bowel Diseases with an emphasis on host-microbe interactions. He has several years of experience working with animal models of experimental colitis and the administration of clinical trials in patients with IBD. On a clinical basis, Michael is interested in health care delivery, especially using dHealth technology and other gastrointestinal disorders including non-alcoholic fatty liver disease, Irritable Bowel Syndrome and Coeliac Disease.

Andrew Reynolds Andrew Reynolds is a postdoctoral fellow with the Department of Medicine at the University of Otago. He has a BSc from La Trobe University, a European MSc, a PhD from the University of Otago, and is currently working towards an MPH. Andrew works with two international guideline development groups and is a board member of the Otago Southland Diabetes Research Trust. He works with randomised trials and systematic reviews pertaining to carbohydrate intake and human health.

Claire Smith Claire Smith works as a Research Fellow in the Department of Women’s and Children’s Health, Dunedin School of Medicine, University of Otago. She is currently researching behavioural factors associated with poor sleep in adolescents. As part of this she is using automated wearable cameras and is interested in practical methods of integrating new technology into traditional dietary assessment techniques. Claire has a long background working with national nutrition survey data, and for her Masters she examined dietary supplement use using the 1997 data set. Claire was employed as part of the Children’s Nutrition Survey 2002 team, and post PhD she analysed and wrote papers on the 2008/09 Adult Nutrition Survey.

Jim Mann Jim Mann has been Professor in Medicine and Human Nutrition at the University of Otago and Consultant Physician (Endocrinology) in Dunedin Hospital for the past 30 years. Previously he lectured at the University of Oxford and was a Physician in the Radcliffe Infirmary. He is Director of the World Health Organisation (WHO) Collaborating Centre for Human Nutrition, the Healthier Lives National Science Challenge and the New Zealand-China Non–Communicable Diseases Research Collaboration Centre and co-Director of the Edgar Diabetes and Obesity Research Centre (EDOR). He is principal investigator for the Riddet Institute, a national Centre of Research Excellence at Massey University. He is a Fellow of the Royal Society of New Zealand and has been awarded the Hercus Medal of the Royal Society and the University of Otago Distinguished Research Medal. He was appointed a Companion of the New Zealand Order of Merit for services to Medicine and medical research.

Paul Moughan Paul Moughan holds the position of Distinguished Professor at Massey University and Riddet Institute Fellow Laureate, having held the position of Foundation Co-Director of the Riddet Institute from 2003-2017. His research has encompassed the fields of human and animal nutrition, food chemistry, functional foods, mammalian growth biology and digestive physiology. In 1995 he was awarded Doctor of Science and in 1997 was awarded a Personal Chair at Massey University and elected a Fellow of the Royal Society of New Zealand. He is a Fellow of the Royal Society of Chemistry, Cambridge, England. In 2011 he was appointed Chair of the FAO Expert Consultation to review recommendations on the characterisation of dietary protein quality in humans, and in 2014 was appointed to the International Think Tank (World Science Academies) on world food security. He has received numerous prestigious international awards for his work, including the New Zealand Prime Minister’s Science Prize in 2012.

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The dietary fibre source influences ileal and hindgut fermentation – a study using combined in vivo/in vitro methodology

This study aimed to compare the ileal and hindgut fermentations from different dietary fibre sources using a combined in vivo/in vitro fermentation assay. Pigs (n=24; 23 kg bodyweight) were fed diets containing 5% cellulose as the sole fibre source (insoluble-fibre) or diets whereby half the cellulose was replaced by either kiwifruit-fibre provided as whole kiwifruit (soluble:insoluble-fibre, ~1:1) or psyllium (soluble-fibre). On day 42, pigs were euthanized, and the small intestine divided into three equal lengths. Digesta from the last 50 cm of the second (terminal jejunum) and last (terminal ileum) thirds of the small intestine were collected as substrates. Digesta from the remaining last third (ileum) were collected along with caecal digesta for preparing inocula. Terminal jejunal digesta were fermented in vitro (2-h) with an ileal inoculum, while terminal ileal digesta were fermented in vitro (24-h) with a caecal inoculum. Ileal organic matter fermentability (OMF) was similar (P>0.05) to hindgut OMF, both 21% on average across dietary treatments. Pigs fed the kiwifruit-diet had greater (P<0.05) predicted ileal productions of butyric and isovaleric acids than predicted hindgut productions. In general, pigs fed the cellulose-diet had the lowest (P<0.05) ileal OMF and predicted short-chain fatty acids (SCFAs) production. However, they had the greatest (P<0.05) predicted hindgut production of some SCFAs. Similar ileal and hindgut predicted production of acetic, isobutyric, pyruvic and succinic acids were found. In conclusion, the kiwifruit-diet was fermented mainly in the ileum, whereas the cellulose-diet was mainly fermented in the hindgut. Ileal fermentation is as important as hindgut fermentation in terms of OMF and SCFA production.

Anika Hoogeveen1,2, Paul Moughan2, Mégane Cognée2, Sharon Henare1,2, Phillip Schulze2, Warren McNabb1,2 and Carlos Montoya2,3

1Massey Institute of Food Science and Technology, Massey University, New Zealand; 2Riddet Institute, Massey University, New Zealand; 3AgResearch Ltd, Grasslands Research Centre, New Zealand

Poster abstracts

In vitro digestion alters faecal fermentation profiles of fibre-rich infant complementary foods Starin McKeen1,2,3, Wayne Young1,2,3, Karl Fraser1,2,3, Nicole C. Roy1,2,3, Warren C. McNabb2,3

1Food Nutrition & Health Team, AgResearch Ltd, Palmerston North, New Zealand 2Riddet Institute, Massey University, Palmerston North, New Zealand 3High-Value Nutrition National Science Challenge, Auckland, New Zealand

Fibre-rich foods, such as New Zealand kumara, which have a resistant starch fraction, are common first foods for infants transitioning from milk-based diets. Infant digestion of starches and fibres is distinct compared to adults, potentially altering the fraction that becomes available as a substrate for gut microbiota, and subsequent microbial fermentation into beneficial metabolites. Of particular interest are short chain fatty acids (SCFAs), which support gut barrier development and have immune modulatory properties. To better understand the prebiotic potential of cooked-cooled-lyophilised kumara as a complementary food, two-stage in vitro digested kumara powder was compared with un-digested kumara powder in an in vitro faecal fermentation experiment using pooled samples collected from two 7-9 month-old infants. Organic acids and SCFAs were analysed using GC-FID at 6 time-points during a 24-hour fermentation. Enzymatic digestion had a significant effect on subsequent fermentation. Undigested kumara produced more acetate, lactate, and succinate, compared to digested kumara. Formate production from digested kumara increased between 4 and 16 hours of fermentation, whereas undigested kumara led to increased formate production between 16 and 24 hours of fermentation. Butyrate and propionate were below detection levels at all time-points for both substrates. The resulting fermentation profiles align with typical abundances of infant hind-gut bacteria implicated in organic acid and SCFA pathways. These results indicate a need to incorporate enzymatic digestion into in vitro fermentation experiments of prebiotic foods, and provide a foundation for further in vitro studies of fibrous infant complementary foods.

Functional equivalents for Healthy Food Design Nutrient-like values for expressing the functional efficacy of foods.

Background: Accurate evidence-based communication of the health benefits of foods and of dietary fibre in foods is a major challenge in functional food science at present because current methods for dietary fibre analysis give no indication of in vivo functional efficacy of fibre, which depends on the properties of fibre under gut conditions at point of action.

Introduction: Functional equivalents are being developed to communicate functional efficacy of foods by expressing an effect of a known weight food or fibre as the weight of a reference material (such as a standard food or fibre), of known and quantified effect, that would induce the same change in a criterion biomarker as the known weight of food.

Principle: The effects of a known weight of food and reference material on a health biomarker are measured under the same conditions. The relative efficacy of the test material with respect to effects on the chosen biomarker may then be expressed in terms of the weight of reference that is functionally equivalent to the given weight of food – its “content” of functional equivalents. Functional equivalents may thus be expressed in the same way as other nutrients, as g/serving and g/100 g food.

Advantages: Ingredients in a food, and foods in a diet, may be combined, based on their content of functional equivalents, to more accurately achieve a sought degree of functionality than by using composition values, such as soluble and insoluble fibre, which are weakly related to functional efficacy.

John MonroNew Zealand Institute for Plant & Food Research, Palmerston North, New Zealand Riddet Institute, Massey University, Palmerston North, New Zealand

Validation of a food frequency questionnaire to assess intake of fibre and fibre-related food groups of relevance to the gut microbiota

Dietary fibre is an important nutrient for the gut microbiota, with different fibre fractions having different effects. The aim of this study was to determine the relative validity and reproducibility of a food frequency questionnaire (FFQ) for estimating intake of fibre (total, soluble and insoluble non-starch polysaccharides) and fibre-related food groups of relevance to the gut microbiota. One hundred parents of 5-year old children completed the 123-item FFQ on two occasions. A 3-day weighed diet record (WDR) was completed between FFQ appointments. Mean correlations between the (randomly chosen) FFQ and WDR were acceptable for fibre and food group intakes (r = 0.34 and r = 0.41 respectively). Gross misclassification was below chance (12.5%) for quartiles of nutrient (mean 5.7%) and food group (mean 5.1%) intake. The FFQ appears to be an appropriate tool for investigating the intake of fibre and fibre-related food groups of relevance to the gut microbiota.

Claudia Leong1,2, Rachael W. Taylor2, Jillian J. Haszard1, Elizabeth A. Fleming1, Gerald W. Tannock3,4, Ewa A. Szymlek-Gay5, Sonya L. Cameron1, Renee Yu1, Harriet Carter1, Li Kee Chee1, Lucy Kennedy1, Robyn Moore1 and Anne-Louise M. Heath1,4

1Departments of Human Nutrition, 2Medicine, 3Microbiology and Immunology, and 4Microbiome Otago, University of Otago; 5School of Exercise and Nutrition Sciences, Deakin University

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Assessing the prebiotic potential of flaxseed mucilage and their stability to cooking conditions

Owing to their established high nutritional profile, flaxseed (Linum usitatissimu), has gained an established reputation as a dietary source of high value functional food ingredients including dietary fibre (Goyal, Sharma et al. 2014, Dzuvor, Taylor et al. 2018). The mucilage in flaxseed is rich in polysaccharides that have demonstrated prebiotic behaviour and able to serve as dietary fibre (Kajla, Sharma et al. 2015). However, little is known of stability of the crude mucilage fractions during processing parameters used in normal cooking procedures.

The aim of this study is to extract complex polysaccharides (mucilage) from flaxseed and assess the effect of cooking conditions (temperature, time, and pH) on the chemical stability and the prebiotic properties of crude flaxseed polysaccharides.

It is expected that conditions such as thermal treatment (boiling) at various pH conditions (acid, base, alkaline) may have the potential to induce hydrolysis of glycosidic bonds in flaxseed mucilage, which in turn can impact the complex polymeric structures as well as the prebiotic potential of flaxseed polysaccharides.

Dzuvor, C., J. Taylor, C. Acquah, S. Pan and D. Agyei (2018). “Bioprocessing of Functional Ingredients from Flaxseed.” Molecules 23(10): 2444.

Goyal, A., V. Sharma, N. Upadhyay, S. Gill and M. Sihag (2014). “Flax and flaxseed oil: an ancient medicine & modern functional food.” Journal of Food Science and Technology 51(9): 1633-1653.

Kajla, P., A. Sharma and D. R. Sood (2015). “Flaxseed—a potential functional food source.” Journal of Food Science and Technology 52(4): 1857-1871.

Thu Minh Nguyen1, Ian Sims2,3, Gerald Tannock2,4, *Dominic Agyei1,2

1Department of Food Science, University of Otago, Dunedin; 2Microbiome Otago, University of Otago, Dunedin; 3Ferrier Research Institute, Victoria University of Wellington, Wellington; 4Department of Microbiology & Immunology, University of Otago, Dunedin

*Corresponding author Tel: +64 3 479 8735; E-mail: Dominic.Agyei@otago.ac.nz

Undigested kiwifruit remnants modulate glycaemic response to co-ingested carbohydrate food

The glycaemic response to ingested carbohydrate foods is governed partly by gut-level processes of digestion that may be affected by digestion-resistant food remnants, including gastric emptying, luminal mixing, diffusion, and enzymatic depolymerisation. Freed from the constraint of fruit structure, after in vitro digestion the settled volume of dispersed kiwifruit flesh debris was four times the flesh volume before digesting, and enough to occupy a large proportion of the foregut free space. The impact of kiwifruit remnants on gut processes involved in the glycaemic response to co-ingested carbohydrate foods was tested in vitro by measuring glucose diffusion, mixing, and pancreatic digestion of carbohydrate staples within the settled dispersion of kiwifruit remnants. The additional effect of introduced hydrocolloid was also measured. Within the settled dispersion of kiwifruit debris glucose diffusion was reduced by about 40 %, simulated intraluminal mixing was reduced by about 50%, and digestion was retarded. Hydrocolloid substantially accentuated the retardation of mixing by kiwifruit remnants. In a subsequent clinical trial meals were formulated to be equal in carbohydrate content and type, but contain cereal plus kiwifruit, or cereal plus kiwifruit sugars, so any differences in meal effects could be attributed to non-available carbohydrate components of the kiwifruit. The meals containing kiwifruit suppressed the glycaemic response to co-ingested wheaten cereal, averted hyperglycaemia, and maintained satiety. The results suggest that dietary fibre from kiwifruit may significantly suppress the glycaemic response to co-ingested carbohydrate through its effects on physical processes of digestion.

J.A. Monro1,2, S. Mishra1

1New Zealand Institute for Plant & Food Research, Palmerston North, New Zealand 2Riddet Institute, Massey University, Palmerston North, New Zealand. john.monro@plantandfood.co.nz

Are we misinterpreting the extent of dietary fibre fermentation in the gastrointestinal tract?

The study aimed to determine the effect of the presence of non-dietary gut materials (e.g. mucins, bacteria) on fibre digestibility and the hindgut production of short-chain fatty acids (SCFAs) in the growing pig. Ileal cannulated pigs were first fed diets with two concentrations of kiwifruit fibre (25 and 50 g/kg diet) for 44 days (adaptation period) followed by a fibre-free diet for seven days (fibre-free period). Ileal digesta and faeces were collected at the end of each period to determine dietary fibre (Prosky method). In addition, ileal digesta were fermented in vitro with a human faecal inoculum to determine the origin of SCFAs. The kiwifruit period values represented both the total undigested fibre and total SCFAs, while the fibre-free period values represented both the interfering non-dietary material in fibre determination and SCFAs of non-dietary origin. In the ileal digesta, mucins were the main source of soluble interfering material, while bacteria were the main source of insoluble interfering material. In the faeces, bacteria were the only source of soluble and insoluble interfering materials. After correcting the apparent ileal and faecal fibre digestibilities for the interfering materials, the digestibility values increased (e.g. +50% units for the ileal digestibility of the soluble fibre fraction of kiwifruit). The SCFAs produced in the hindgut were higher from non-dietary (65%) than dietary fibre (26%) sources. In conclusion, a large amount of non-dietary material is present in ileal digesta and faeces that can lead to misleading conclusions concerning both fibre digestibility and the production of SCFAs.

Carlos A. Montoya1,2, Paul J. Moughan2

1Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand; 2Riddet Institute, Palmerston North, New Zealand

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How does fibre structure affect microbiota functionality?

Dietary fibre is the main substrate fermented by the human gut microbiota1, thereby significantly impacting colonic microbial composition and metabolism2. By understanding more about how fibre affects the microbiota, we hope to develop dietary interventions to modulate the microbiota for optimum health. Recent work highlighted that individuals with a low abundance of methane-producing organisms in the gut (methanogens), have a low abundance of “keystone” species3. Keystone species can help to stabilise the gut community through their specialised role in fibre digestion4,5. Low abundance of keystone species can reduce the benefits of fibre consumption for the host. However, not all fibre is equal. The impact of methanogens and keystone species on fibre utilisation may differ depending on fibre structure. The objective of this research is to investigate how different dietary fibre structures are digested and metabolised by the gut microbiota in individuals with high and low methanogen abundance. Methanogen abundance will be determined using a methane breath test3. Faecal samples will be used for in vitro simulated colonic fermentation. Dietary fibres differing in structure will be added to the fermentation. Metagenomics, transcriptomics and metabolomics will be used to understand how different fibres are digested and metabolised by the microbiota in those individuals.

1. Cummings JH, Englyst HN. Fermentation in the human large intestine and the available substrates. Am J Clin Nutr. 1987;45:1243–55.

2. Flint HJ, Juge N . Role of microbes in carbohydrate digestion. Food Sci Technol. 2015;1–6.

3. Robert C, Bernalier-Donadille A. The cellulolytic microflora of the human colon: Evidence of microcrystalline cellulose-degrading bacteria in methane-excreting subjects. FEMS Microbiol Ecol. 2003;46(1):81–9.

4. Ze X, Le Mougen F, Duncan SH, Louis P, Flint HJ. Some are more equal than others: The role of “keystone” species in the degradation of recalcitrant substrates. Gut Microbes. 2013;4(3).

5. Walker AW, Ince J, Duncan SH, Webster LM, Holtrop G, Ze X, et al. Dominant and diet-responsive groups of bacteria within the human colonic microbiota. ISME J [Internet]. 2011;5(2):220–30. Available from: http://dx.doi.org/10.1038/ismej.2010.118

Payling, L.1,2, Roy, N.1,2,4, Fraser, K.2,4, Loveday, S.M.2 , Sims, I.3, McNabb, W.11Riddet Institute, Massey University, Tennent Drive, Palmerston North; 2AgResearch Grasslands, Tennent Drive, Palmerston North; 3Ferrier Research Institute, Victoria University of Wellington; 4High-Value Nutrition National Science Challenge

Snack product (re)formulation in the improvement of health effects on glyceamia and satiety responses

Snacking impacts on the overall quality of dietary patterns, nutrition and health outcomes. Highly processed snack foods are normally unhealthy due to higher saturated fat content, refined grains (carbohydrates), and artificial ingredients. Snack product (re)formulation using plant-based wholesome ingredients has a potential in the improvement of health effects on glycaemia and satiety responses.

Oat (Avena sativa L.) has gained increased popularity as a food item in recent decades due to its perceived or real health benefits, principally related to the bran content of oats. Working in partnership with a food company, a healthier snack prototype has been developed using rolled oats as main ingredients. Other ingredients include oat bran, dried fruits, and nuts. The ingredients were trialled in different combination and composition to produce a formula having a good nutrient profiling score (≤ 4) that meets the criteria (FSANZ) for making health-related claims, and taste acceptable. The proportions of the ingredients in the formula were adjusted to enable higher fibre and protein contents.

The prototype has been tested for glyceamic index (n=10) and consumer liking (n=67). The results revealed that the prototype has a low glycemic index, favorable satiety effects compared with glucose, and taste acceptable. The health effects on glycaemia, insulin profiles of the prototype will be studied.

High value nutrition is the New Zealand national science challenge. Developing healthier snack products through reformulation with verifiable health-related claims, such an approach could be translated into relevant dietary changes associated with potential improvement of public health.

Yan, M.1,2, Rush, E.2, Shaikh, S.11Health and Community Network, Unitec Institute of Technology, Auckland, New Zealand; 2AUT Food Network, Auckland University of Technology, Auckland, New Zealand

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Notes

EDGAR DIABETES &OBESITY RESEARCHA UNIVERSITY OF OTAGO RESEARCH CENTRE

Edgar Diabetes and Obesity ResearchReducing the global burden of diabetes and obesity throughresearch and dissemination of knowledge

We aim to reduce the prevalence, and to improve the management, of diabetes and obesity by finding new ways to prevent and treat these conditions. By striving for research excellence and encouraging international collaboration we can bring the greatest benefit to New Zealanders and the wider world.

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Riddet InstituteWorld Leading research in food science and nutrition

The Riddet Institute is a premier centre for fundamental and strategic scientific research and training a new generation of science leaders. Its area of expertise is at the intersection of food material science, novel food processing, human nutrition and gastrointestinal biology. The Institute integrates partner organisations and disciplines, leading a “NZ Inc.” approach to food research, and generates knowledge and capability that transforms the New Zealand food industry.

Tel 64 6 951 7295 Email info@riddet.ac.nz Web www.riddet.ac.nz LinkedIn linkedin.com/company/riddet-institute

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