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Title: The substitution of dietary saturated fatty acids with monounsaturated and n-6 polyunsaturated fatty acids on measures of vascular function and risk factors of cardiovascular disease
Author: Weech, Michelle
Awarding Body: University of Reading
Current Institution: University of Reading
Date of Award: 2013
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A systematic review of the evidence indicated that vascular function, a critical early modifiable event in cardiovascular disease (CVD) development, can be modulated by dietary fat composition. Saturated fat (SF A) was deleterious, with limited evidence of benefit for monounsaturated (MUFA) or n-6 polyunsaturated fat (n-6 PUFA). Studies were difficult to compare, due in part to the varying methods of vascular function determination, and on analysis, it was confirmed that these methods were not interchangeable (except pulse wave velocity and stiffness index). It was hypothesised that substituting SFA with MUFA or n-6 PUFA would improve vascular function and traditional CVD risk markers, with differential responses dependent on endothelial nitric oxide synthase (NOS3) genotype. A large parallel, randomised, controlled intervention was conducted in adults with mild risk of CVD (n=195). Using a novel food exchange model, three 16-wk isoenergetic diets (SFA-, MUFA- and n-6 PUFA rich) were implemented in free-living individuals. Target intakes were broadly met (assessed using 4-day diet records (P <0.001) and plasma phospholipid fatty acids (P <0.001 for total SFA and MUFA» , without weight change. Replacement of SFA with MUFA or n-6 PUFA did not influence vascular function, although SFA deteriorated macro- and microvascular endothelial function (P <0.05), but improved the lipid profile (P = 0.001) and CVD risk score (P = 0.003). Replacement with MUFA attenuated the SF A-induced increase in night blood pressure (P <0.05) and reduced circulating ESelectin (P = 0.025). NOS3 genotype influenced responses to the dietary manipulation differentially in males and females. Genotype*diet interactions (P <0.05) were identified for reflection index (measuring vascular tone) and triacylglycerol in females, and non-esterified fatty acids in males. In conclusion, replacing SF A with MUF A and n- 6 PUFA significantly reduces CVD risk, although the optimal replacement appears dependent on NOS3 genotype and gender, providing an effective public health strategy for reducing cardiovascular risk in a population with mild risk of CVD.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available