GLOSSARY

Omega-3 Fatty Acids Table

Linoleic acid and alpha-linolenic acid are indispensable parent fatty acids; EPA and DHA are not interchangeable gram for gram with ALA.

Essential Fatty Acids (EFAs) require dietary provision; linoleic and alpha-linolenic acids are the principal members, rather than every omega fatty acid or all fats.

Essential members: 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.

Naming: 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.

The body can convert some alpha-linolenic acid into EPA and DHA, but conversion is limited and varies between people and conditions. A gram of the precursor is not equivalent to a gram of either product. Walnuts and flaxseed remain useful foods; direct provision requires separately considering fish or an appropriate algal product.