Effects of dietary extra virgin olive oil on serum lipid resistance to oxidation and fatty acid composition in elderly lipidemic patients

An inverse relation between high consumption of olive oil and low incidence of coronary heart disease among the people living in Mediterranean countries has been proposed. It has been shown, that an oleic acid-rich diet could increase the resistance of human LDL to in vitro oxidation which is postulated to play an important role in the development of atherosclerotic lesions. The aim of this study was to assess the effect of extra virgin olive oil consumptiom on the resistance of serum lipids to in vitro oxidation and on fatty acid composition in the serum of elderly lipidemic patients. A total of 26 patients (mean age 69 years) with combined hyperlipidemia consumed daily 2 table spoons (approx. 20 g) of extra virgin olive oil for 6 weeks. Plasma lipids, total antioxidant capacity, indices of serum lipid oxidizability (lag time and maximal rate of oxidation) and the content of fatty acids in serum phospholipids were determined before and after dietary supplementation with olive oil. Plasma total cholesterol and LDL cholesterol decreased significantly after 6 weeks of dietary intervention. A significant increase in the lag time of conjugated diene formation (p = 0.026) and the decrease in the rate of lipid oxidation (p = 0.030) were observed after olive oil consumption. The changes in the fatty acid profile were characterized by an increase in oleic acid content (p = 0.005) as well as by a decline in the content of linoleic acid (p = 0.020) and arachidonic acid (p = 0.022). Linear regression analysis revealed some interesting and significant correlations between indices of serum lipid resistance to oxidation and individual fatty acids, suggesting a protective effects of olive oil in lipoprotein oxidation. In conclusion, the daily consumption of extra virgin olive oil in elderly lipidemic patients favourably affected serum lipoprotein spectrum and fatty acid composition that probably contributed to the increased resistance of serum lipids to oxidation. (Tab. 2, Ref. 18).