EFFECTS OF SPECIFIC FATTY-ACIDS (8 0, 14/0, CIS-18/1, TRANS-18/1) ON PLASMA-LIPOPROTEINS, EARLY ATHEROGENIC POTENTIAL, AND LDL OXIDATIVE PROPERTIES IN THE HAMSTER/

Although comparative studies of the cholesterolemic properties of tran s fatty acids relative to cis-unsaturates and saturates have been cond ucted in humans and animals, there is no recent information relating t hese lipid responses to susceptibility to atherosclerosis. Therefore, hamsters were fed diets containing equivalent amounts of cholesterol ( 0.12% wt/wt) and test fats (20% wt/wt) for 8 weeks. Each test fat cont ained between 50-52% of the total triacylglycerols as a single fatty a cid, i.e., 8:0, 14:0, 18:0, cis-18:1, or trans-18:1 while the balance consisted of 16:0, cis-18:1 and 18:2 that were the same for all groups . Plasma total cholesterol (TC), low density lipoprotein cholesterol ( LDL-C), and high density lipoprotein cholesterol (HDL-C) levels were n ot different for 8:0, cis-18:1, and trana-18:1, whereas 14:0 caused a significant rise in plasma TC, LDL-C, and HDL-C. LDL oxidation measure ments showed that the lag phase of conjugated diene formation was long est for the trans-18:1 and cis-18:1 groups while rate of conjugated di ene formation was lowest for the trans-18:1 and cis-18:1 groups. The t rans-18:1- and cis-18:l-fed animals had significantly higher levels of LDL alpha-tocopherol relative to the 8:0- and 14:0-fed animals. Aorti c fatty streak formation Tvas highest for the 14:0- and 8:0-fed animal s and lowest for the trans-18:1. In conclusion, the plasma lipid and a ntioxidant properties of trans-18:1 and cis-18:1 were comparable while the trans-18:1-fed hamsters had the least amount of early atheroscler osis, In addition, 8:0-fed animals unexpectedly had early atherosclero sis formation similar to the 14:0-fed animals.