Efficacy of high-oleic canola and flaxseed oils for cardiovascular disease risk reduction

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dc.contributor.authorGillingham, Leah
dc.contributor.examiningcommitteeAukema, Harold (Human Nutritional Sciences) Friel, James (Human Nutritional Sciences) Jassal, Davinder (Internal Medicine) Field, Catherine (University of Alberta)en_US
dc.contributor.supervisorJones, Peter (Food & Human Nutritional Sciences)en_US
dc.date.accessioned2012-08-27T19:29:32Z
dc.date.available2012-08-27T19:29:32Z
dc.date.issued2011-02en_US
dc.date.issued2011-03en_US
dc.date.issued2012-06en_US
dc.degree.disciplineFood and Nutritional Sciencesen_US
dc.degree.levelDoctor of Philosophy (Ph.D.)en_US
dc.description.abstractConsiderable interest has focused on the influence of dietary fat quality on cardiovascular disease (CVD) risk. Increasingly, novel dietary oils rich in oleic acid and alpha-linolenic acid (ALA) are being developed and marketed with an aim to improve fatty acid intakes and reduce CVD risk. The objective of this research was to investigate the efficacy of high-oleic canola oil (HOCO) alone, or blended with flaxseed oil (FXCO), on traditional and emerging clinical biomarkers of CVD risk. An additional aim was to study the influence of dietary and genetic factors on metabolism of 13C-ALA to long-chain PUFA. Using a diet-controlled randomized crossover design, thirty-six hypercholesterolaemic subjects consumed three isoenergetic diets for 28 days each containing ~36% energy from fat, of which 70% was provided by HOCO, FXCO, or a Western dietary fat blend (WD; control). Endpoint measures revealed reductions (P<0.001) in serum lipid concentrations, including a 7.4% and 15.1% decrease in LDL-cholesterol after HOCO and FXCO diets, respectively, as compared with the WD control. Moreover, a reduction (P=0.023) in plasma E-selectin concentration was found after the FXCO diet compared with the WD control. Consumption of the dietary oils failed to alter whole-body fat oxidation or energy expenditure, nor lead to alterations in body composition. FXCO diet increased (P<0.001) plasma ALA ~5-fold, EPA ~3-fold, and DPA ~1.5-fold, but did not modulate DHA levels compared with the WD control. At 24 and 48 hours the amount of administered 13C-ALA recovered as plasma 13C-EPA and 13C-DPA was lower (P<0.001) after FXCO diet compared with HOCO and WD diets, suggesting decreased ALA conversion efficiency with very high intakes of dietary ALA. No difference in plasma 13C-DHA enrichment was observed across diets. Moreover, minor alleles of selected single nucleotide polymorphisms in the FADS1/FADS2 gene cluster were associated with reduced (P<0.05) plasma fatty acid compositions and apparent conversion of 13C-ALA. However, increased consumption of ALA in the FXCO diet compensated for lower levels of EPA in minor allele homozygotes. Taken together, substitution of dietary fats common to WD with both HOCO and FXCO represents an effective strategy to target several biomarkers for CVD risk reduction.en_US
dc.description.noteOctober 2012en_US
dc.identifier.citationGillingham LG, Gustafson JA, Han SY, Jassal DS, Jones PJ. High-oleic rapeseed (canola) and flaxseed oils modulate serum lipids and inflammatory biomarkers in hypercholesterolaemic subjects.Br J Nutr 2011 Feb;105(3):417-27en_US
dc.identifier.citationGillingham LG, Harris-Janz S, Jones PJ. Dietary monounsaturated fatty acids are protective against metabolic syndrome and cardiovascular disease risk factors. Lipids 2011 Mar;46(3):209-28.en_US
dc.identifier.citationGillingham LG, Robinson KS, Jones PJ. Effect of high-oleic canola and flaxseed oils on energy expenditure and body composition in hypercholesterolemic subjects. Metabolism (2012), doi:10.1016/j.metabol.2012.04.016en_US
dc.identifier.urihttp://hdl.handle.net/1993/8485
dc.language.isoengen_US
dc.publisherCambridge University Pressen_US
dc.publisherSpringeren_US
dc.publisherElsevieren_US
dc.rightsopen accessen_US
dc.subjectFlaxseeden_US
dc.subjectcanolaen_US
dc.subjectcardiovascular diseaseen_US
dc.subjectlipiden_US
dc.subjectmetabolismen_US
dc.titleEfficacy of high-oleic canola and flaxseed oils for cardiovascular disease risk reductionen_US
dc.typedoctoral thesisen_US
local.subject.manitobayesen_US
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