The Acute Effect of Soluble Dietary Fibre-Enriched Pudding Products on Glycemic and Insulinemic Response in Adults at Risk for Type 2 Diabetes by Brittney A. Kay A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Master of Science in Human Health and Nutritional Sciences Guelph, Ontario, Canada © Brittney A. Kay, January, 2016 ABSTRACT The Acute Effect of Soluble Dietary Fibre-Enriched Pudding Products on Glycemic and Insulinemic Response in Adults at Risk for Type 2 Diabetes Brittney A. Kay Advisors: University of Guelph, 2016 Alison M. Duncan, Amanda J. Wright Type 2 Diabetes (T2D) is a chronic loss of the ability to regulate blood glucose, therefore dietary interventions capable of modulating glycemic response are rationalized. A randomized, double-blinded, crossover study was conducted to investigate effects of soluble dietary fibres (DF) (yellow mustard mucilage (YMM), fenugreek gum (FG), flaxseed mucilage (FM)) added to pudding on acute postprandial glycemic response in adults (n=15) at risk for T2D. Results showed significant time by treatment interactions for glucose and insulin, with the soluble DF puddings being lower than the control at some time points. Peak glucose and insulin were also significantly lower with all soluble DF puddings compared to control, although 2-hour incremental area under the curves did not differ. Therefore, YMM, FG and FM have the ability to alter glycemic response in individuals at risk for T2D, suggesting their potential as dietary strategies for individuals who could benefit from alterations in glycemic response. ACKNOWLEDGEMENTS I am so thankful for the opportunities I have had while working on my Master’s, while in the department of Human Health and Nutritional Sciences. Everyone in the department, and those involved with the Human Nutraceutical Research Unit (HNRU), have been so instrumental as mentors in guiding who I am as a researcher and a professional, and have really allowed me to grow. There are many people who have supported the research throughout the entire process, and I will be forever grateful to them. First, I would like to thank my advisors, Dr. Alison Duncan and Dr. Amanda Wright. Alison and Amanda, you have been such amazing mentors, and have really guided me in strengthening who I am as a researcher, and for that I am so thankful. You have always pushed me to succeed throughout the research process, and have always been there to support me when I’ve needed help along the way. You are both such strong individuals, and accomplish so many things. I’m happy to have been a part of your team! I would also like to thank Dr. Douglas Goff, and PhD candidate Nikolay Repin, who designed our pudding products, and worked closely with our team from start to finish for the clinical trial. I have learned a lot about Food Science, especially in regard to our fibre types and designing of our pudding products, and I enjoyed working with both of you. To all members of the Pudding Study team (past and present), and also the HNRU team, especially Dr. Amy Tucker, it was an amazing two years. I firmly enjoyed working with every one of you, especially the M.Sc. Coursework students on our team, including Melissa, Kristina, Shannon, and Robbie, who I have also built amazing friendships with. Without the dedication of everyone on the team our study would not have been so successful, and I thank everyone for their help. iii I also want to thank all of my amazing friends I have met in this program that weren’t directly apart of the Pudding Study team, but definitely had a major impact on my life during the two years, especially Agota, Sarah Dainty, Sarah Heap, Caitlin, Erin, and Élie. Thank you for being so encouraging and positive, and allowing me to always have friends to rely on. You are all such amazing, and aspiring individuals, and I’m so happy to have you all in my life. Furthermore, I would like to thank my family and friends, for which I feel have really carried me through this whole process. Mom, Dad, Brandon, and Tannis, you’ve definitely been there when I’ve needed you the most, and have always been so encouraging and proud of me throughout my education. I am so happy to have all of you in my life, and words cannot express how much I love you! I also need to thank my furry best friend, Astro, who has always been by my side, and has always showered me with affection. Finally, I’d also like to thank all of my friends outside of academia for being there for me throughout the two years, especially Alice, Maida, Jared, Christina, and all of my Black’s Photography co-workers (especially Mo, Shannon, Kirsten, Greg, and Davide). You’re all people I admire and care deeply for, and have definitely allowed me to learn so much about myself. Thank you for making me laugh, allowing me to cry, and always supporting me along the way. Finally, I have to thank all of the participants who made this research possible. I firmly enjoyed spending my mornings getting to know everyone, and feel that each person has taught me so many things to bring forward into my next stage of life. I was so lucky to have such amazing participants who were so dedicated, caring, and detail oriented. I’m glad you decided to participate in the Pudding Study! iv TABLE OF CONTENTS ABSTRACT .................................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................................... iii LIST OF TABLES ....................................................................................................................... viii LIST OF FIGURES ....................................................................................................................... ix LIST OF APPENDICES ................................................................................................................. x LIST OF ABBREVIATIONS ........................................................................................................ xi INTRODUCTION ....................................................................................................................... 1 1. Type 2 Diabetes ................................................................................................................ 1 a. Prediabetes and Type 2 Diabetes: a Concern Worldwide and in Canada .................... 1 b. Screening for Type 2 Diabetes ..................................................................................... 2 c. Type 2 Diabetes Disease Development and Symptoms ............................................... 4 d. Risk Factors for Type 2 Diabetes ................................................................................. 7 2. Dietary Fibre .................................................................................................................. 10 a. Dietary Fibre and its Physiochemical Properties ........................................................ 10 b. Dietary Fibre Canadian Recommendations ................................................................ 11 3. Type 2 Diabetes and Dietary Fibre ................................................................................ 12 a. Type 2 Diabetes and Dietary Fibre – An Overview ................................................... 12 b. Mucilage Gum Hydrocolloids – A Type of Soluble Fibre ......................................... 14 c. Yellow Mustard Seed and Yellow Mustard Mucilage ............................................... 15 d. The Role of Yellow Mustard Mucilage in Modulating Glycemic Response ............. 16 e. Fenugreek and Fenugreek Gum .................................................................................. 18 f. The Role of Fenugreek Seeds and Fenugreek Gum in Modulating Glycemic Response 18 f.i. Fenugreek Seeds Acute Human Intervention Studies............................................. 19 f.i.i. Fenugreek Gum Acute Human Intervention Studies ............................................ 31 g. Flaxseed and Flaxseed Mucilage ................................................................................ 33 h. The Role of Flaxseed and Flaxseed Mucilage in Improving Glycemic Response ..... 34 h.i. Flaxseed Acute Human Intervention Studies ......................................................... 35 h.i.i. Flaxseed Mucilage Acute Human Intervention Studies ....................................... 36 RESEARCH RATIONALE ...................................................................................................... 40 PURPOSE, OBJECTIVES AND HYPOTHESIS ..................................................................... 44 v 1. Research Purpose, Objectives and Hypotheses .............................................................. 44 METHODS................................................................................................................................ 45 1. Study Design and Approvals .......................................................................................... 45 a. Study Design............................................................................................................... 45 b. Study Approvals ......................................................................................................... 45 2. Participant Sample Size, Recruitment, Screening, and Orientation ............................... 46 a. Participant Sample Size Determination .....................................................................