linolenic

Linolenic is a term used for groups of polyunsaturated fatty acids with three cis double bonds and 18 carbon atoms. The most commonly discussed forms in nutrition are alpha-linolenic acid (ALA) and gamma-linolenic acid (GLA). ALA, with the designation 18:3n-3, is an essential omega-3 fatty acid in humans, meaning it must be obtained from the diet because the body cannot synthesize it. GLA, designated 18:3n-6, is an omega-6 fatty acid that is not considered essential, but it is a metabolite of linoleic acid and occurs in certain seed oils.

Dietary sources: ALA is abundant in flaxseed and flaxseed oil, chia seeds, walnuts, hemp seeds, and canola oil. GLA is found in evening primrose oil, borage oil, and black currant seed oil, among other seed oils and supplements.

Biochemical role and metabolism: ALA can be elongated and desaturated to longer-chain omega-3 fatty acids, notably EPA and, to a lesser extent, DHA, but conversion in humans is limited and varies with age, sex, and overall diet. Because of the low conversion, direct intake of EPA and DHA from animal or algal sources is often recommended for omega-3 intake. GLA is converted to dihomo-gamma-linolenic acid (DGLA) and participates in biosynthesis of certain eicosanoids; its effects are context-dependent and studied in relation to inflammation and skin health.