ALA (Alpha-Linolensäure): the pathway in the body

ALA (Alpha-Linolensäure) is part of the pathway “Omega-3 fatty acids”. This page shows the whole pathway; the station of ALA (Alpha-Linolensäure) is highlighted.

Where this laboratory value sits: ALA — Alpha-linolenic acid. ALA is the plant omega-3 fatty acid from linseed, rapeseed and walnut. The body cannot make it itself; it has three double bonds and 18 carbon atoms. Source 1

In brief

Omega-3 fatty acids such as ALA, EPA and DHA are polyunsaturated fatty acids whose first double bond lies at the third carbon from the end of the chain. The body builds them into cell membranes and forms messengers such as resolvins from EPA and DHA.

The pathway step by step

1. ALA → Stearidonic acid FADS2 (Δ6-desaturase) · NADH, cytochrome b5 Δ6-desaturase (FADS2) inserts another double bond. The same enzyme also processes omega-6 fatty acids, which compete with the omega-3 fatty acids for access to it. Source 1, 2
2. Stearidonic acid → Eicosatetraenoic acid ELOVL5 (elongase) · Malonyl-CoA, NADPH An elongase (ELOVL5) adds two carbon atoms; malonyl-CoA supplies the building block and NADPH the electrons. Source 2
3. Eicosatetraenoic acid → EPA FADS1 (Δ5-desaturase) · NADH, cytochrome b5 Δ5-desaturase (FADS1) inserts the fifth double bond. EPA has twenty carbon atoms and is the starting material for its own group of messengers. Source 1, 3
4. EPA → DPA ELOVL2 (elongase) · Malonyl-CoA, NADPH The elongase ELOVL2 lengthens EPA by two further carbon atoms. Source 2
5. DPA → DHA ELOVL2, FADS2 · Peroxisomal shortening To form DHA, the chain is first lengthened and desaturated further; in the peroxisome a breakdown step then shortens it again by two carbon atoms. In humans this route runs only to a small extent. Source 2, 1
6. 18-HEPE → E-series resolvins 5-lipoxygenase 5-lipoxygenase converts 18-HEPE further. The resulting resolvins bind to dedicated receptors on immune cells and are among the substances the body uses to end an inflammatory response. Source 5, 3
7. In membrane lipids → Resolvins, protectins 15-LOX, 5-LOX · Phospholipase A2 Phospholipase A2 releases DHA again. A 15-lipoxygenase converts it into 17-HpDHA, from which D-series resolvins, protectins and maresins are formed. Source 5, 3

Cofactors in this pathway

• Niacin (NADH, NADPH) — NADH supplies the electrons for the desaturases, NADPH for the elongases Source 2In the ORY catalogue as a laboratory value: NAD⁺ (Nicotinamidadenindinukleotid)
• Iron — Metal centre of the lipoxygenases that form resolvins from EPA and DHA Source 6In the ORY catalogue as a laboratory value: Eisen
• Biotin — Cofactor of acetyl-CoA carboxylase, which forms the malonyl-CoA for the elongases Source 7
• Pantothenic acid (coenzyme A) — Building block of coenzyme A in malonyl-CoA and in activated fatty acids Source 2
• Calcium — A rise inside the cell activates cytosolic phospholipase A2, which releases fatty acids Source 8In the ORY catalogue as a laboratory value: Calcium (intrazellulär)
• Vitamin E — Scavenges peroxyl radicals in membranes containing polyunsaturated fatty acids Source 9In the ORY catalogue as a laboratory value: Vitamin E (Tocopherol)

Sources

1. Burdge GC, Calder PC. Metabolism of alpha-linolenic acid in humans. Prostaglandins Leukot Essent Fatty Acids 2006 · PubMed 16828546
2. Qiu X. Biosynthesis of docosahexaenoic acid (DHA, 22:6-4, 7,10,13,16,19): two distinct pathways. Prostaglandins Leukot Essent Fatty Acids 2003 · PubMed 12538082
3. Dyall SC, Balas L, Bazan NG et al. Polyunsaturated fatty acids and fatty acid-derived lipid mediators: Recent advances in the understanding of their biosynthesis, structures, and functions. Prog Lipid Res 2022 · PubMed 35508275
4. Hishikawa D, Valentine WJ, Iizuka-Hishikawa Y et al. Metabolism and functions of docosahexaenoic acid-containing membrane glycerophospholipids. FEBS Lett 2017 · PubMed 28833063
5. Chiang N, Serhan CN. Specialized pro-resolving mediator network: an update on production and actions. Essays Biochem 2020 · PubMed 32885825
6. Wood I, Trostchansky A, Rubbo H. Structural considerations on lipoxygenase function, inhibition and crosstalk with nitric oxide pathways. Biochimie 2020 · PubMed 32980463
7. Tong L. Striking Diversity in Holoenzyme Architecture and Extensive Conformational Variability in Biotin-Dependent Carboxylases. Adv Protein Chem Struct Biol 2017 · PubMed 28683917
8. Leslie CC. Cytosolic phospholipase A2: physiological function and role in disease. J Lipid Res 2015 · PubMed 25838312
9. Traber MG, Atkinson J. Vitamin E, antioxidant and nothing more. Free Radic Biol Med 2007 · PubMed 17561088

Whole pathway: Omega-3 fatty acids

Related pathways

• Omega-6 fatty acids and eicosanoids — epa
• Calprotectin — Eisen, Calcium (intrazellulär)
• Carnitine — NAD⁺ (Nicotinamidadenindinukleotid), Eisen
• Citric acid cycle — NAD⁺ (Nicotinamidadenindinukleotid), Eisen
• Coenzyme Q10 — NAD⁺ (Nicotinamidadenindinukleotid), Vitamin E (Tocopherol)

As of 2026-09-16. Draft written by Claude to schema v2; sources checked in PubMed; expert review pending
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