Lipid extracts isolated from heat processed food show a strong agglutinating activity against human red blood cells

In this study we investigated the possibility that the lipid components of foodstuffs and mass market oils undergo oxidative and thermal changes during storage, processing and cooking and so become agglutinins. The hemagglutinating activity of several mass market oils and several lipid mixtures isolated from different food items was evaluated against human red blood cells (RBCs) and against hamster RBCs. The unheated oils and the lipid extract of the unheated foodstuff had a very low agglutination titer but lysed red cells at high concentrations. When the same foodstuff items and oils were heated (100 degreesC for 24 h) in air, the isolated mixture of lipids as well as the oils show a strong hemagglutinating activity. Thin layer chromatography (TLC) of the lipid mixture. isolated from the processed foodstuff, as well as the heated samples of the oils showed appearance of high molecular weight molecules, possibly dimers and polymers. Light microscopy was used to characterize and visualize the agglutination process. Agglutination without lysis or fusion was observed. Agglutination may be the result of membrane properties alteration due to the oxidation product insertion or by hydrophobic side chain insertion into adjacent RBC membranes. We conclude that oils and foodstuff items when heated in air produce hemagglutinins against human RBCs with unknown and possibly toxic effects on human health. (C) 2002 Elsevier Science Ltd. All rights reserved.