A diet containing rapeseed oil-based fats does not increase lipid peroxidation in humans when compared to a diet rich in saturated fatty acids

Abstract

Objective: To compare the effects of a rapeseed oil-based diet containing an increased proportion of easily oxidised polyunsaturated fatty acids such as a-linolenic acid with a diet rich in saturated fatty acids on the degree of lipid peroxidation in the human body. Design: A randomised cross-over study. Subjects and interventions: Nineteen healthy moderately hyperlipidemic subjects (six women and 13 men, age 50 AE 8 y and body mass index (BMI) 24.5 AE 2.6 kg=m 2 ) were given a rapeseed oil-based diet (RO) and a control diet (SAT) rich in saturated fatty acids during two consecutive 4 week periods separated by a 4 week wash-out period. Biomarkers of lipid peroxidation and antioxidants were analysed in plasma and urine. Results: No significant differences in plasma or urinary levels of free 8-iso-prostaglandin F 2a , plasma total 8-isoprostaglandin F 2a plasma hydroperoxides or plasma malondialdehyde were observed between the RO and SAT diets (P ¼ 0.14 -0.95). A higher concentration of serum g-tocopherol was detected after the RO diet compared to the SAT diet (P < 0.001), whereas the serum a-tocopherol concentration and plasma antioxidative capacity did not differ between the two test diets. The total cholesterol, LDL cholesterol and LDL=HDL ratio were lower after the RO diet compared to the SAT diet (P < 0.001), while HDL cholesterol and total triglyceride levels were similar after the two diets. Conclusion: These results suggest that a rapeseed oil-based diet rich in a-linolenic acid does not seem to increase the degree of lipid peroxidation in plasma and urine compared to a diet rich in saturated fats. This is possibly due to a sufficient content of antioxidants in the rapeseed oil diet to increase circulating concentrations of antioxidants that may protect unsaturated fatty acids from oxidation.

Replacing dairy fat with rapeseed oil causes rapid improvement of hyperlipidaemia: a randomized controlled study

“…In the latter study, when 20% of daily energy intake as vegetable SFA (palm oil) was replaced with RO for 5 weeks, LDL cholesterol levels decreased by 18%, which is in line with results from the present study, despite the fact that slightly less fat was substituted in that study [32]. The reduction from baseline values in total (17%) and LDL (17%) cholesterol levels was greater in the present study than in a similar Swedish 4‐week controlled study in healthy subjects [33] (11% and 11%, respectively), although both the amounts of fat and the fatty acid compositions of the diets were comparable in the two studies. The greater lipid‐lowering effect seen in the present study might be because of the somewhat higher blood lipid levels of the current hyperlipidaemic patients or may in part be explained by different baseline or control diets and the amounts of fat in the intervention diets.…”

“…For instance, in a study in which larger amounts of butter were replaced with MUFA from an RO‐based margarine, LDL cholesterol decreased by 29.5% [34]. However, the reduction in total/HDL cholesterol ratio by 21% in the current study is greater than that observed following most previous interventions using RO (or canola oil) [2, 3, 8, 33, 35–37] and even exceeds mathematical predictions [29]. We did not observe any effects on HDL cholesterol, which is in line with previous studies [2, 3, 33–37].…”

Effects of α-linolenic acid supplementation in perilla oil on collagen-epinephrine closure time, activated partial thromboplastin time and Lp-PLA 2 activity in non-diabetic and hypercholesterolaemic subjects

“…Serum total-cholesterol and LDL-cholesterol decreased by 8% and 12%, respectively, in the ALA group after supplementation -similar effects have been observed in previous studies using ALA-rich oils (Bemelmans et al, 2002;Finnegan et al, 2003b;Södergren et al, 2001;Umesha & Naidu, 2012;Zhao et al, 2004). ALA has a limited capacity for conversion into longer-chain n-3 fatty acids, such as EPA, DPA and DHA.…”

Effect of linolenic acid on cardiovascular risk markers: a systematic review

“…Table 1 shows selected characteristics of the included trials. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Body weight and blood pressure Six studies measured body weight and three 4-6 reported systolic and diastolic blood pressures. Three reported the body mass index 4 6 7 and three 5 8 9 reported weight.…”