Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.
Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Senior Scientist Guy Vergeres, Agroscope
- Second opponent: Associate Professor Bodil Bjørndal, HVL - Western Norway University of Applied Sciences
- Third member and chair of the evaluation committee: Associate Professor Anne-Marie Aas, University of Oslo
Chair of the Defence
Associate Professor Thomas Sæther, Faculty of Medicine, University of Oslo
Principal Supervisor
Professor Stine Marie Ulven, Faculty of Medicine, University of Oslo
Summary
Replacing saturated fatty acids (SFA) with polyunsaturated fatty acids (PUFA) is associated with reduced cardiovascular disease (CVD) risk. This effect is largely mediated through lowering of serum low-density lipoprotein (LDL) cholesterol, which is a well-characterized CVD risk factor. Intake of n-3 PUFAs may also lower serum triglycerides (TG), and is proposed to have anti-inflammatory effects. However, the molecular mechanisms that link dietary fatty acids and such physiological effects are not fully understood.
The overall aim of this thesis was to explore the molecular mechanisms underlying the effect of dietary fat quality on CVD risk by use of transcriptome profiling of peripheral blood mononuclear cells (PBMC) in human studies.
In a cross-sectional study, Larsen et al. found that plasma SFA to PUFA ratio was associated with a higher number of differently expressed genes than n-6 and n-3 PUFA levels, and that several of these genes were related to cholesterol homeostasis. Further, in a dietary intervention study, they found that TG responders (ΔTG ≤ −20 %) and non-responders (−20 % < ΔTG < +20 %) to n-3 PUFA supplementation had different baseline gene expression profiles and differently altered gene expression profiles and pathways after seven weeks. Finally, in a randomized controlled dietary intervention study, they found that replacing dietary SFAs with PUFAs for eight weeks favourably altered the expression of several genes associated with processes related to CVD risk, and that the change in expression of some of these genes were correlated to change in serum cholesterol levels. Furthermore, several pathways were differently altered between the two intervention groups.
In conclusion, the findings in this thesis support that fat quality is associated with PBMC gene expression, which may contribute to extend our understanding of how dietary fat affects CVD risk and why individuals respond differently to n-3 PUFA intake.
Additional information
Contact the research support staff.