Trans‐fatty acids: an introduction

Fats and oils contain triglycerides that are esters formed between the alcohol glycerol and fatty acids. Unsaturated fatty acids contain carbon‐carbon double bonds. For such a double bond, cisand trans‐isomers are possible. The overwhelming majority of unsaturated fatty acids from plant oils are cis. In margarine manufacture,double bonds are hydrogenated so as to increase the melting points of the oil. A consequence of this is that a proportion of the double bonds remaining becomes trans. The proportion of trans‐fatty acids in some margarines is around 20 per cent. Argues that the implications of this for human health are worrying. Trans‐fatty acids have been implicated as the possible cause of a number of health problems. Recent research has identified that this isomer is the cause of an increased level of low‐density lipoprotein cholesterol.