MEATS AND FISH CONSUMED IN THE AMERICAN DIET CONTAIN SUBSTANTIAL AMOUNTS OF ETHER-LINKED PHOSPHOLIPIDS

The primary goal of this study was to determine the amounts of ether-containing phospholipids, along with their concentration of certain polyunsaturated acyl groups, from selected, commonly consumed foods of animal origin (salmon, catfish, pork, beef, turkey and chicken). Levels of ether-linked glycerolipids in the samples were of particular interest, because ingestion of ether lipids could contribute to the production of platelet-activating factor (PAF; 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine), one of the most potent biological mediators known. Alkylacyl-sn-glycero-3-phosphocholine was found in all of the meats, with pork loin having the highest levels (0.9-mu-mol/g tissue) and chicken breasts the lowest (0.1-mu-mol/g tissue). Although choline plasmalogens were not as evident as the ubiquitous ethanolamine plasmalogens, substantial amounts (1.0-mu-mol/g tissue) of alk-1-enylacyl-sn-glycero-3-phosphocholine were found in tissues from beef and turkey. Triacylglycerols contained greater proportions of saturated fatty acids than phospholipids, and the ether-linked phospholipids were generally more unsaturated than diacyl species of the same phospholipid. Our data indicate that in addition to the phospholipid fraction of commonly eaten animal tissues supplying substantial amounts of polyunsaturated fatty acids, they are also a rich source of ether-linked lipids. Dietary ether-linked phospholipids could influence the lipid composition of host tissues to the extent that biological responses produced by ether lipid mediators would be affected.