High-oleic rapeseed (canola) and flaxseed oils modulate serum lipids and inflammatory biomarkers in hypercholesterolaemic subjects.

Key Findings:

Dyslipidaemia, specifically elevated LDL-cholesterol, is a primary risk factor in predicting CVD events and a major target of dietary intervention. The reduction of both circulating LDL-cholesterol levels and inflammatory biomarkers is important in ameliorating CVD risk. After consumption of the ALA-rich FXCO diet, an approximate 5-fold increase in plasma ALA (18 : 3n-3) concentrations and 3-fold increase in EPA (20 : 5n-3) concentrations were observed. An increase in plasma concentration of ALA, EPA and DPA after the consumption of the FXCO diet may be cardioprotective as an inverse association has been found between plasma concentrations of combined EPA and DHA, as well as of ALA, and risk of fatal IHD. The present study is the first human clinical trial to investigate effects of HOCO on serum lipids and other markers of CVD risk. HOCO alone or when blended with flaxseed oil effectively reduced serum TC and LDL-cholesterol compared with a WD. Moreover, the ALA-rich FXCO may further target inflammation and atherogenic pathways by reducing plasma E-selectin. Substitution of dietary fats common to the WD with both HOCO and flaxseed oil is a feasible option to target dietary recommendations and risk factors for CVD.

ABSTRACT

Recently, novel dietary oils with modified fatty acid profiles have been manufactured to improve fatty acid intakes and reduce CVD risk. Our objective was to evaluate the efficacy of novel high-oleic rapeseed (canola) oil (HOCO), alone or blended with flaxseed oil (FXCO), on circulating lipids and inflammatory biomarkers v. a typical Western diet (WD). Using a randomised, controlled, crossover trial, thirty-six hypercholesterolaemic subjects consumed three isoenergetic diets for 28 d each containing approximately 36% energy from fat, of which 70% was provided by HOCO, FXCO or WD. Dietary fat content of SFA, MUFA, PUFA n-6 and n-3 was 6, 23, 5, 1% energy for HOCO; 6, 16, 5, 7·5% energy for FXCO; 11·5, 16, 6, 0·5% energy for WD. After 28 d, compared with WD, LDL-cholesterol was reduced 15·1% (P < 0·001) with FXCO and 7·4% (P < 0·001) with HOCO. Total cholesterol (TC) was reduced 11% (P < 0·001) with FXCO and 3·5% (P = 0·002) with HOCO compared with WD. Endpoint TC differed between FXCO and HOCO (P < 0·05). FXCO consumption reduced HDL-cholesterol by 8·5% (P < 0·001) and LDL:HDL ratio by 7·5% (P = 0·008) v. WD. FXCO significantly decreased E-selectin concentration compared with WD (P = 0·02). No differences were observed in inflammatory markers after the consumption of HOCO compared with WD. In conclusion, consumption of novel HOCO alone or when blended with flaxseed oil is cardioprotective through lipid-lowering effects. The incorporation of flaxseed oil may also target inflammation by reducing plasma E-selectin.