GLOSSARY

Polyunsaturated Fats refers to dietary sources containing polyunsaturated fatty acids; nuts, seeds, vegetable oils and fish provide different mixtures.

Walnuts and fish can both fit weekly meals, but their shared category does not give them identical EPA and DHA contents.

Most foods contain mixtures of fatty acids: olive oil is not exclusively monounsaturated, and nuts do not contain only one fat type. Naming a food after its predominant fraction does not imply purity. Food selection should consider the overall composition, portion, accompanying fibre or protein and what the food replaces.

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.

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.

The fish-oil amount on a package front is not necessarily its EPA and DHA content; other fatty acids may make up a substantial fraction. Compare each component per actual serving and identify the source. Algal oil can also provide a direct source, but formulations vary and marine branding does not guarantee quantity or purity.

The effect of reducing one fat depends on its replacement. Substituting unsaturated oils or nuts for some butter differs from adding oil to an unchanged diet. Replacing it only with sugary, low-fibre foods is not equivalent. Carbohydrate quality and total energy should be considered alongside the fatty-acid change.

More double bonds can increase susceptibility to oxidation, but temperature, heating duration, light, air and naturally present antioxidants also matter. Smoke point alone is not a complete stability or health score. Closed storage away from light and heat, and avoiding repeated severe overheating, are useful practical measures when handling oils.