linoleic

Linoleic acid, commonly referred to as linoleic, is an essential omega-6 polyunsaturated fatty acid. It is an 18-carbon fatty acid with two cis double bonds at the 9th and 12th positions (18:2 n-6, also called cis,cis-9,12-octadecadienoic acid). Humans cannot synthesize linoleic acid and must obtain it from the diet.

Dietary sources are primarily vegetable oils such as sunflower, safflower, corn, and soybean oils, as well as nuts, seeds, and some animal fats. In many populations, linoleic acid provides a substantial portion of daily fat intake. Dietary guidelines vary by country, but linoleic acid is generally recommended as part of a balanced fat intake, with attention to overall omega-6 to omega-3 balance.

Biologically, linoleic acid serves as a structural component of cell membranes and is a precursor to longer-chain omega-6 fatty acids such as arachidonic acid. Through enzymatic desaturation and elongation, it contributes to the synthesis of eicosanoids, which participate in inflammation, immunity, and vascular function. It is also important for skin integrity and normal growth.

Health considerations include ensuring adequate intake, particularly in populations with low fat consumption. Some evidence suggests that replacing saturated fats with linoleic acid can lower LDL cholesterol, but a very high omega-6 intake relative to omega-3 may influence inflammatory pathways if omega-3 intake is insufficient. Because linoleic acid is polyunsaturated, it is prone to oxidation; storage in cool, dark conditions and careful cooking can mitigate this.