Sunflower oil does not protect against LDL oxidation as virgin olive oil does in patients with peripheral vascular disease.

BACKGROUND & AIMS: The aim of this study was to compare the in vivo effects of a diet rich in virgin olive oil or sunflower oil on the lipid profile and on LDL susceptibility to oxidative modification in free-living Spanish male patients with peripheral vascular disease. METHODS: A total of 20 Spanish male subjects diagnosed with peripheral vascular disease were randomly divided into two groups (n = 10) receiving different supplements, virgin olive oil and sunflower oil for 4 months. RESULTS: The adaptation of patients to the experimental supplements was demonstrated since plasma and LDL fatty acids composition reflected dietary fatty acids. No differences in triglycerides, total cholesterol, LDL-cholesterol or HDL-cholesterol concentrations were found between the groups of patients. A significantly higher LDL susceptibility to oxidation was observed after sunflower oil intake in comparison with virgin olive oil, in spite of an increase in LDL alpha-tocopherol concentration in sunflower oil group. CONCLUSIONS: The results of the present study provide further evidence that sunflower-oil-enriched diets does not protect LDL against oxidation as virgin olive oil does in patients with peripheral vascular disease.

Virgin olive and fish oils enhance the hepatic antioxidant defence system in atherosclerotic rabbits.

BACKGROUND & AIMS: In this study we report the effects of sunflower, virgin olive and fish oils on the lipid profile and antioxidant defence system in liver mitochondria from rabbits with experimental atherosclerosis. METHOD: An atherogenic control group were fed for 50 days on a diet containing 3% lard and 1.3% cholesterol. Four groups were fed for an additional period of 30 days with a diet enriched in different oils: sunflower oil, virgin olive oil, refined olive oil and fish oil. A control group was fed with a standard chow. RESULTS: The atherogenic diet caused important changes in the hepatic mitochondria lipid profile and in the enzymatic and non-enzymatic antioxidant defence system accompanied with an increase in the content of hydroperoxides in liver mitochondria. The administration of virgin olive and fish oils showed a better profile in the antioxidant system as well as decrease in the content of hydroperoxides. CONCLUSIONS: The intake of cholesterol- and lard-enriched diet leads to a high impairment in the hepatic antioxidant defence system. However, the replacement of that diet by other unsaturated fat-enriched diets using virgin olive, sunflower and fish oil enhances hepatic antioxidant defence system, virgin olive and fish oil diet provide the best results.

Sunflower, virgin-olive and fish oils differentially affect the progression of aortic lesions in rabbits with experimental atherosclerosis.

In this study we report the effects of sunflower, virgin olive and fish oils on the progression of aortic lesions. A total of 24 male New Zealand rabbits (six per each group) were fed for 50 days on a diet containing 3% lard and 1.3% cholesterol, to induce atherosclerosis. An atherogenic control group (A) was killed after this period and three groups were fed for an additional period of 30 days with a diet composed of (1.75 g of supplemented oil and 98.25 of standard chow): sunflower oil (S), virgin olive oil (O) and fish oil (F). A control group (n=6) was fed with a standard chow diet for 80 days. LDL lipid composition and histological analysis of aortic atherosclerotic lesions were assayed. The atherogenic diet caused a significant increase of cholesterol levels in LDL and aorta tissue. Cholesterol ester content rose significantly in the aortic arch of groups S, O and F. Fatty streaks were found in all aortic sections, although only group S showed a significant progression of the lesion compared with group A. We conclude that the replacement of a high cholesterol-saturated fat diet by another cholesterol free-unsaturated fat diet does not regress atherosclerosis in rabbit. However, sunflower oil provokes a significant progression in lesion development, whereas diet enrichment with extra virgin olive oil and, to a lesser extent, fish oil, stops this progression.

[Protective effect of monounsaturated and polyunsaturated fatty acids on the development of cardiovascular disease]. / Efectos protectores de los ácidos grasos monoinsaturados y poliinsaturados sobre el desarrollo de la enfermedad cardiovascular.

Cardiovascular disease has a multifactorial aetiology, as is illustrated by the existence of numerous risk indicators, many of which can be influenced by dietary means. In this article, the effects of unsaturated fatty acids on cardiovascular disease are reviewed, with special emphasis on the modifications of the lipoprotein profile and the mechanism by which fatty acids may affect the immune response on the development of the atherosclerotic lesion. Atherosclerosis occurs fundamentally in three stages: dysfunction of the vascular endothelium, fatty streak and fibrous cap formation. Each of the three stages is regulated by the action of vasoactive molecules, growth factors and cytokines, mediators of the immune response. Dietary lipid quality can affect the lipoprotein metabolism, altering their concentrations in the blood, permitting a greater or lesser recruitment of them in the artery wall. The replacement of dietary saturated fat by mono- or polyunsaturated fats significantly lowers the plasma-cholesterol and LDL-cholesterol levels. Likewise, an enriched monounsaturated fatty acid diet prevents LDL oxidative modifications more than an enriched polyunsaturated diet, and the oxidation of LDL in patients with peripheral vascular disease mediated by n-3 fatty acids can be reduced by the simultaneous consumption of olive oil. However, strong controversy surrounds the effect of the different unsaturated fatty acids. The type of dietary fat can directly or indirectly influence some of the mediating factors of the immune response; n-3 fatty acids have powerful antiinflammatory properties. Dietary fatty acids strongly determine the susceptibility of lipoproteins to oxidation, which also has an impact on the activation of molecules of adhesion and other inflammatory factors. Moreover, several works have demonstrated a direct effect of fatty acids on the genetic expression of many of those factors. Finally, certain aspects of blood platelet function, blood coagulability, and fibrinolytic activity associated with cardiovascular risk, are modulated by dietary fatty acids; n-3 fatty acids strongly inhibits platelet aggregation and activate thrombolytic processes.

Influence of dietary lipids on lipoprotein composition and LDL Cu(2+)-induced oxidation in rabbits with experimental atherosclerosis.

The aim of this study was to investigate the composition of plasma lipoproteins and their susceptibility to oxidation in rabbits with experimental atherosclerosis provoked by the intake of a diet rich in cholesterol and saturated fat as well as the influence of the intake of four diets differing in their lipid profiles (fish (F), refined olive (R), virgin olive (V) and sunflower (S) oils) on plasma lipoprotein composition and susceptibility to oxidation of these atherosclerotic rabbits. Plasma and lipoproteins concentrations of cholesterol, phospholipids and triglycerides were markedly higher in atherosclerotic rabbits but decreased with the experimental diets. LDL oxidation damage increased in atherosclerotic rabbits; the F diet led to a higher LDL oxidation susceptibility whereas groups fed either S, R, or V showed LDL oxidation values close to those of the control group. Diets rich in monounsaturated and n-3 polyunsaturated oils showed efficacy in restoring the normal lipid profiles in atherosclerotic rabbits provided in fish oil is adequately stabilized with antioxidants.