GLOSSARY

Polyunsaturated Fatty Acids (PUFAs) have two or more double bonds; omega-3 and omega-6 are important families, but their members are not all equally essential or functionally identical.

Saturation concerns carbon–carbon double bonds in a fatty-acid chain, not fullness after eating or a food's energy content. One double bond defines monounsaturation; multiple bonds define polyunsaturation. Their positions and cis or trans geometry also matter, so counting bonds alone cannot explain every physical property or biological effect.

The omega number locates the first double bond from the methyl end, which differs from the carboxyl end. Total carbon number and total double bonds are separate information. Omega therefore names a structural family rather than a quality score or speed of action; members can differ in length, food sources and function.

Linoleic and alpha-linolenic acids are essential because humans cannot synthesise their structures from scratch. Essential means that a dietary supply is needed, not that unlimited amounts are beneficial. Different oils, nuts and seeds contribute to this supply. Severely removing all fats can make adequate intake of these fatty acids difficult.