Trans Fatty Acids: Their Chemical Structures, Formation and Dietary Intake

Trans fatty acids are unsaturated fatty acids with at least a double bond in trans configuration or geometry. The double-bond angle of the trans fatty acids is smaller than the cis isomeric configuration and the acyl chain is more linear, resulting in a more rigid molecule with different physical properties such as a higher melting point and greater thermodynamic stability. These appear in dairy fat because of ruminal activity, and in hydrogenated oils. Trans unsaturated fatty acids are solid fats produced artificially by heating liquid vegetable oils in the presence of metal catalysts and hydrogen. Trans fatty acids are found in numerous foods. Margarines, shortenings and baked goods contain relatively high levels of trans fatty acids. Similar to saturated fatty acids, trans fatty acids also increase LDL cholesterol and lower HDL cholesterol therefore increasing the risk of heart diseases. Therefore, the possible increase in risk for those diseases caused by a high trans fatty acid consumption should be carefully considered.