Trans fatty acids—Occurrence, technical aspects, and worldwide regulations

The fat consumption in the human diet is based on the intake of two types of fatty acids, namely, saturated (SFA) and unsaturated (UFA) fatty acids. Unsaturated fatty acids, which are grouped into monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), have been scientifically proven to positively contribute to human health when consumed in a regular diet. However, one of the isomers occurring in the carbon chain, which are called trans fatty acids (commonly "trans fats"), gained specific interest due to their adverse health effects. Trans fatty acids either occur naturally or are the components derived during oil processing such as partial hydrogenation, refining, and deep-fat frying. Since the physicochemical attributes of the fatty acids change when shifting from cis to trans isomerization, trans fats have been widely studied to reveal their impacts on humans. Even though naturally occurring trans fats are considered less harmful than artificial trans fats, the risk of being negatively affected by trans fatty acids in regard to issues such as cardiovascular diseases, diabetes, obesity, several cancers, asthma, allergic reactions, and increased LDL cholesterol is a worldwide medical concern in general. In the last two or three decades, there was a great interest in processed foods such as shortenings, potato chips, margarine, fast food, snacks, and fried foods due to their desirabilities by consumers, but their trans-fat contents made these products to be questioned soon. Today, many countries and organizations have been conducting investigations to limit the maximum amount of trans fats in such processed foods with a high content of fat. This chapter aims to provide further information about the nature, occurrence, and global regulations of trans fatty acids.