Polyunsaturated fatty acids contain n3 and n6 fatty acids, including the essential fatty acids (EFA), as the body cannot synthesise these. The only EFA in the n-6 series is linoleic acid and in the n-3 series, is alpha-linolenic acid, the most common Omega-3 fatty acid. ^[2,3]

The remaining fatty acids in this category are not considered to be essential fatty acids.

The long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are found in a seafood only and can be synthesised from alpha linolenic acid (ALA), but the conversion efficiency is low. ^[1]

As per the World Health Organization guidelines, polyunsaturated fats intake goals are set to be around 6 to 10 E%. 1 to 2 E% for n-3 fatty acids and 5 to 8 E% for n-6 fatty acids, where E % is the percentage of total dietary energy (E%), or as ‘grams per day’ for adults. ^[3]

Good plant sources of omega-3 fats include vegetable oils, such as soybean, safflower, canola, soybean, and corn oil; nuts such as walnuts; seeds such as flaxseeds; and some vegetables. ^[1,4]

Also, replacing calories from carbohydrates with equivalent calories from monounsaturated fats can reduce mortality risk by 11% ^[7].

The n-6 fatty acids are almost completely absorbed. ^[2]

Polyunsaturated fatty acids are oxidised to carbon dioxide and water. ^{[2] ]}

Small amounts are lost via the sloughing of skin and other epithelial cells. ^[2]