Factors affecting gut metabolism and bioavailabilty of orange juice flavanones in humans

Hou, Min (2015) Factors affecting gut metabolism and bioavailabilty of orange juice flavanones in humans. PhD thesis, University of Glasgow.

Abstract

Several studies have supported a beneficial role of dietary flavonoids in reducing the risk/progression of chronic diseases (including hypertension, cardiovascular disease, certain cancers, type-2-diabetes, cognitive dysfunction, age-related bone disease). Their beneficial properties are likely to be affected by their structure, distribution in foods, food matrix, life habits (physical activity). Most dietary polyphenols reach the colon where they are metabolized to phenolic acids by gut bacteria. Lack of knowledge of the factors affecting flavonoid metabolism and bioavailability hinders understanding of their health effects. Therefore, this thesis aimed to investigate the effect of factors on bioavailability and metabolism of dietary polyphenols from orange juices (OJ) in in vitro and in vivo studies. In chapter 3, the variability of orange juice polyphenolic content was assessed using in vitro models of the human gastrointestinal tract. Chapter 4 investigated the reduced urinary phenolic acids after OJ and yoghurt (Y) in humans compared to OJ alone using in vitro models of the human gut. In chapter 5, raftiline and glucose were tested for effects on metabolism of hesperidin (flavanone not OJ). In chapter 6, an intervention study of 4 weeks moderate intensity exercise determined whether exercise affected bioavailability and metabolism of OJ flavanones in healthy sedentary females. The studies in this thesis showed that food sources, food matrix and physical exercise may determine the significant variations in bioavailability and metabolism of flavonoids, seen in a number of studies. These factors could result in differences in bioactivity and bioefficacy of polyphenols, and need to be taken into account in further studies of the effects of flavanones on disease risk.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Bioavailability, gut metabolism, orange juice flavanone, food source, food matrix, physical activity.
• Subjects: R Medicine > R Medicine (General)
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
• Supervisor's Name: Edwards, Professor Chrisitne and Combet Aspray, Dr. Emilie
• Date of Award: 2015
• Depositing User: Miss Min Hou
• Unique ID: glathesis:2015-7372
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 26 May 2016 12:50
• Last Modified: 29 May 2017 12:43
• URI: https://theses.gla.ac.uk/id/eprint/7372