Intensification of Essential Fatty Acid Deficiency in the Rat by Dietary trans Fatty Acids

Two studies were conducted using male rats to assess the effect of trans fatty acids upon essential fatty acid (EFA) deficiency. In the first study 5% corn oil (CO), hydrogenated coconut oil (HCNO) or margarine stock (MS, partially hydrogenated soybean oil) were fed, and the levels of trans fatty acids in tissue lipids were measured. The trans fatty acids present in MS were found to intensify EFA deficiency and to be retained in tissue lipids to a high degree, especially in heart phospholipids (PL). In the second study, as the level of trans fatty acids increased in the diet, increasingly higher levels of trans fatty acids were deposited in the heart PL. As dietary trans acids increased, a decrease in total ω6 fatty acids, and a decrease in the sum of 18:2ω6 + 20:4ω6-20:3ω92 fatty acids in heart PL occurred, both criteria indicating a shift toward an increasing EFA deficiency state. Studies of Δ5 desaturase activity of liver microsomes in selected groups showed an increase in the conversion of 20:3ω6 to 20:4ω6 as the trans fatty acid level in the diet increased.