- Title
- Investigating objective biomarkers to characterise addictive eating
- Creator
- Skinner, Janelle Angela
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The worldwide prevalence of overweight and obesity has almost tripled in the past 50 years. According to the World Health Organization (2016), around 2 billion adults are classified as overweight and of those 650 million classified as obese (BMI >30kg/m2). Contemporary changes in the food environment (e.g. widespread availability and accessibility to hyperpalatable foods, increasing portion sizes, growth of supermarkets and food marketing) has been a contributor to the rising prevalence of obesity. As societies face increasing healthcare costs due to obesity-associated morbidity reversing the obesity “pandemic” has become a priority in public health. Evidence for the concept of addictive eating, largely driven by an over-consumption of hyperpalatable foods, has steadily been growing over the past two decades. If better understood, may offer a new approach to developing more effective obesity prevention and treatment strategies for individuals with addictive eating. At present addictive eating behaviour is assessed through self-report measures. This thesis investigated a range of appetite and appetite-related hormones, with a focus on oxytocin, and heart rate variability (HRV), to determine their potential to serve as objective biomarkers to characterise addictive eating behaviour. These biomarkers were examined in the context of ‘food addiction’ status and weight status in Australian adults. The foundations of the studies in this thesis arise from systematic reviews of preclinical (Chapter 3) and clinical (Chapter 2) studies conducted to consolidate evidence of the role oxytocin plays in the modulation of food intake and eating behaviours. Image paradigms of healthy and hyperpalatable foods were constructed (Chapter 4) to examine the effects of visual food cues on biomarkers and are used in the ensuing chapters. Plasma oxytocin concentrations (Chapter 5) and HRV (Chapter 6), carried out as pilot studies, were measured in samples of adults of varying weight status, with and without self-reported food addiction. This thesis research identified a positive correlation between BMI and plasma oxytocin in females and provides insights that the appetite-related hormones, oxytocin and cholecystokinin, may be dysregulated in individuals with addictive eating behaviours and overweight/obesity. A hypothesis arising from this finding is that in some individuals, despite higher concentrations of oxytocin, a decreased sensitivity to oxytocin may result in an inability to sense satiety signals making it more difficult to regulate food intake, particularly hyperpalatable foods. Higher BMI was found to be associated with lower HRV. In response to visual food cues, an overall deceleration in heart rate occurred, with healthy images prompting a significantly larger cardiac deceleration than hyperpalatable foods. However, responses to food cues did not significantly differ between adults with and without self-reported food addiction. Taken collectively the results from this thesis further our understanding of the individual differences that exist in oxytocin concentrations and HRV in those with and without addictive eating behaviours. Future studies in larger sample sizes could reveal a role for oxytocin and HRV in food addiction. Given that individuals are frequently exposed to cues of hyperpalatable food, which trigger the motivation to eat, significant findings offer the potential to provide novel insights into the pathophysiology of addictive eating behaviour. The findings reported in this thesis provide a novel contribution to addictive eating behaviour research by considering objective biomarkers, beyond the self-reported assessment tools that are currently used, for future application in both laboratory and free-living settings.
- Subject
- addictive eating; food addiction; biomarker; obesity; appetite hormones; oxytocin; dietary intake; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1421901
- Identifier
- uon:37778
- Rights
- Copyright 2020 Janelle Angela Skinner
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 6 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 333 KB | Adobe Acrobat PDF | View Details Download |