- Title
- Association of dietary patterns and macronutrient intake with type 2 diabetes risk
- Creator
- Alhazmi, Amani
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2014
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Type 2 diabetes is a pervasive health crisis that threatens all nations. The epidemic has grown in parallel with the increase in obesity due to different factors, including nutrition transition. This thesis comprises four interconnected research stages that aim to contribute to the evidence base informing associations of dietary patterns and macronutrient intake in relation to type 2 diabetes risk. The first aim of this thesis was to review the existing evidence for the association of macronutrients and dietary patterns with type 2 diabetes risk by conducting two systematic literature reviews and meta-analyses. The existing evidence on the association of macronutrient intake and dietary patterns with type 2 diabetes risk was synthesised (Chapter 3). The first review found that while total carbohydrate is associated with an increased risk of type 2 diabetes, high vegetable fat intake may decrease the risk. The evidence from the second review showed that adherence to a healthy dietary pattern was inversely associated with type 2 diabetes risk, whereas an unhealthy dietary pattern was positively associated with the disease. These reviews highlighted the need for well-designed prospective cohort studies to further examine these associations. The second aim was to investigate the association between macronutrient intake and type 2 diabetes in middle-aged Australian women. A prospective cohort study of 8370 Australian women from the Australian Longitudinal Study on Women’s Health (ALSWH) aged 45–50 years and free of type 2 diabetes at baseline with six years (2002–2007) of follow up was undertaken (Chapter 4). Dietary intake was assessed with a self-reported validated food frequency questioner (FFQ) and the association between macronutrients and type 2 diabetes was investigated using multiple logistic regressions adjusted for potential confounding variables. After the six-year follow-up, 311 women developed type 2 diabetes. The data indicate that consumption of monounsaturated fatty acid (MUFA), total omega-3 polyunsaturated fatty acid (n-3 PUFA), Alpha-linolenic acid (ALA), and omega-6 polyunsaturated fatty acid (n-6 PUFA) may increase the risk of developing type 2 diabetes in women. The potential association between fatty acids and type 2 diabetes found in the above study was further investigated in a nested case-control study of 187 adults aged 55–85 years from the Hunter Community Study (HCS) (Chapter 5). The study aimed to examine the association of fasting whole blood fatty acid concentrations with incident type 2 diabetes. The results suggested that higher fasting whole blood concentrations of omega-6 polyunsaturated fatty acids (n-6PUFA) arachidonic acid (ARA) and dihomo-gamma-linolenic acid (DGLA) as well as ALA, Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) are associated with an increased risk of diabetes, whereas increased fasting whole blood concentrations of lignoceric acid is inversely associated with diabetes risk. These findings may negate previous evidence and emphasise the critical need for further investigations in this area. Focus then shifted to investigate the association between diet and type 2 diabetes in a prospective cohort study using a complementary approach to determine the ability of two diet-quality scores to predict the incidence of type 2 diabetes (Chapter 6). The methods employed in this study were similar to those of the first prospective cohort study. The study suggested that the risk of type 2 diabetes in Australian women with the highest diet quality score as measured by the Dietary Guideline Index (DGI) was about 50% lower than those with the lowest diet quality score. Taken together, the research outlined herein provides detailed data on the associations between macronutrient intake and dietary patterns in relation to type 2 diabetes risk. The thesis concludes with reflections on the implications of its findings for nutrition research and key recommendations for ongoing research in this area. It suggests that a well-designed, adequately powered intervention research investigating the effect of these dietary factors in relation to type 2 diabetes risk is necessary to form future recommendations on preventive dietary approaches.
- Subject
- dietary patterns; type 2 diabetes; macronutrients
- Identifier
- http://hdl.handle.net/1959.13/1055826
- Identifier
- uon:15943
- Rights
- Copyright 2014 Amani Alhazmi
- Language
- eng
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| View Details Download | ATTACHMENT02 | Thesis | 1 MB | Adobe Acrobat PDF | View Details Download |