Journal Name:
British Journal of Nutrition
Article Title:
Different effects of diets rich in olive oil, rapeseed oil and sunflower-seed oil on postprandial lipid and lipoprotein concentrations & on lipoprotein oxidation susceptibility
Date Written:
2002
Volume:
87
Number:
Page:
489
Author(s):
Nielsen, N.; Perdersen, A.; Sandstr�m, B.; Marckmann, P.; Hoy, C.
Article:
Individuals suffering from ischemic heart disease (IHD), as well as offspring of IHD patients, display an exaggerated triacylglycerol (TAG) response to fat-containing meals. It has been hypothesized that delayed catabolism of chylomicron (CM) remnants may be involved in the pathogenesis of atherosclerosis and IHD. Additional studies have demonstrated that consumption of different types of unsaturated fatty acids results in different postprandial TAG responses. In addition, the oxidative damage of lipoproteins may also contribute to the initial events leading to IHD. A comparison of the effects of diets rich in different unsaturated fatty acids including olive, rapeseed (canola) and sunflower oils, on the concentrations and in vitro oxidation of fasting and postprandial lipoproteins was assessed in this study.
Eighteen healthy males, aged 20-28 years, participated in a double blind randomized cross over study. Subjects had no family history of atherosclerotic disease or hypertension. The participants consumed three separate experimental diets, each for a three-week period, with 4 - 12-week washout periods between. The diets were designed to have a total fat content of approximately 30%. 50g per 10MJ of rapeseed oil (RO), olive oil (OO), or sunflower seed oil (SO) were incorporated into the diets corresponding to 19% energy. Lunch was consumed at the institute on weekdays, while other meals were pre-packaged for consumption at home. At the end of each 3-week period (day 22), volunteers were given two meals (1.6 and 5.8 MJ) separated by 1h 45min. Both meals consisted of a low-fat basic rice dish (9% energy from fat) enriched with RO to a total of 43% energy. Blood samples were obtained from fasting volunteers prior to start of the study, and on day 22 of each test period. Non-fasting blood samples were also collected on day 22 - 4h 15min, 5h 45min, and 8h 45min after the first meal. Analysis was subsequently performed for determination of cholesterol and TAG lipoproteins, as well as oxidation of LDL and VLDL.
At the conclusion of the study, fasting and postprandial total plasma and lipoprotein-TAG concentrations differed significantly between diets. Intake of OO was associated with a significantly higher postprandial plasma CM and VLDL-TAG in comparison to RO and SO, while RO and SO diets resulted in similar responses. Propagation rates for VLDL and LDL oxidation were higher in the postprandial state in comparison to the fasting state, irrespective of the diet. Propagation rates in the both fasting and postprandial state were highest after the SO diet. SO consumption also gave rise gave rise to a shorter VLDL lag time and a higher propagation rate than OO consumption. The SO diet resulted in a higher postprandial propagation rate of LDL in comparison to RO and OO; however, there was no effect of diet on LDL oxidation lag time.
These results suggest that consumption of RO and SO diets are preferable to OO in regard to effects on plasma lipid levels, while the OO diet is preferable to RO, and especially SO, in terms of in vitro oxidation of lipoproteins. The authors also noted that the claimed cardio protective effects of OO may be related to lower oxidation susceptibility, rather than favorable postprandial lipid and lipoprotein responses. RO (canola oil) is the preferred dietary oil as a result of its more favorable effects on plasma lipids in comparison to both OO and SO as well as to its moderate effects on lipid oxidation related to SO., , ,
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