LDL and HDL oxidation and fatty acid composition in vegetarians

The oxidation of low-density lipoproteins (LDL) and high-density lipoproteins (HDL) and fatty acid composition, which may affect the resistance of lipoproteins to oxidation, were determined in 24 lacto-ovo vegetarians. Vegetarian diets contain more essential polyunsaturated fatty acids (PUFAs). Therefore, the relationship between LDL and HDL oxidation resistance measured by the kinetics of the formation of fatty acid conjugated dienes (lag time, maximal rate of oxidation and maximal amount of conjugated dienes), LDL and HDL fatty acid composition and vitamin E content were evaluated. All parameters of in vitro oxidation were significantly lower in HDL when compared with LDL. The relative values of arachidonic, dihomo-gamma -linoleic and docosahexaenoic acid were significantly higher in HDL, alpha -linolenic acid content significantly lower, when compared with LDL; the peroxidizability index was significantly higher in HDL. The content of vitamin E was found more than 2-fold lower in HDL particles. The results show the importance of fatty acid composition in the resistance of LDL and HDL to oxidation and from this aspect, the composition of LDL isolated from vegetarians seems to be more favourable compared to HDL. Copyright (C) 2001 S. Karger AG, Basel.