Introduction: Identifying dietary interventions for cardiometabolic disease prevention in individuals with metabolic syndrome is relevant to a significant portion of the population. Numerous studies have investigated the effects of canola oil on cardiovascular disease risk; however, no studies have compared canola oil diets to a control diet with a fatty acid composition characteristic of Western intakes in individuals with metabolic syndrome risk factors. The objectives of this study were to evaluate effects of canola oil, high-oleic acid canola oil (HOCO), and a control oil (blend of butter, safflower, coconut, and flaxseed oils formulated to represent a Western diet fatty acid profile) on lipids, lipoproteins, and apolipoproteins.
Hypothesis: We tested the hypothesis that the two canola oil diets would elicit beneficial effects on the total lipid/lipoprotein profile compared to the Western (control oil) diet.
Methods: In a multi-center, double blind, randomized, three-period crossover, controlled feeding clinical trial, 119 individuals with an increased waist circumference plus at least one additional metabolic syndrome risk factor consumed prepared isocaloric, weight maintenance diets containing canola oil [17.5% E from monounsaturated fatty acids (MUFA), 9.2% polyunsaturated fatty acids (PUFA), 6.6% saturated fatty acids (SFA)], HOCO (19.1% E from MUFA, 7.0% PUFA, 6.4% SFA), or control oil (11% E from MUFA, 10% PUFA, 12% SFA) for six-weeks each separated by 4-12 week washouts. The differences at the end of 42 days of feeding were tested.
Results: The canola oil and HOCO resulted in lower endpoint total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), the TC: high-density lipoprotein-cholesterol (HDL-C) ratio, apolipoprotein (apo) B, the apoB: apoA1 ratio, and non-HDL-C compared to control oil (P<0.0001 for treatment effect), with no differences between HOCO and canola oil for these parameters. Endpoint apoA1 did not significantly differ between the two canola oils and control, but was higher after the HOCO compared to canola oil (1.46 ± 0.02 g/L vs. 1.43 ± 0.02 g/L, P = 0.0462). There were no differences among the three diets in endpoint triglycerides or HDL-C.
Conclusions: Incorporating canola or high-oleic acid canola oils into the diet improves blood lipids and lipoproteins compared to a contemporary Western diet in individuals with at least two criteria for metabolic syndrome.