Alpha-Linolenic Acid (DB00132): A Comprehensive Scientific Review

I. Introduction to Alpha-Linolenic Acid (ALA)

Alpha-linolenic acid (ALA) is an 18-carbon polyunsaturated fatty acid (PUFA) belonging to the omega-3 (n-3) family.[1] It holds the distinction of being an essential fatty acid (EFA) for humans and other mammals, meaning it is indispensable for normal physiological function but cannot be synthesized de novo within the body.[3] Consequently, ALA must be obtained entirely from dietary sources. This inherent biological limitation underscores ALA's critical nutritional status and necessitates its inclusion in dietary recommendations to prevent deficiency and support overall health.

ALA serves as the parent compound for the entire omega-3 fatty acid series. While it can be metabolically converted into longer-chain, more unsaturated omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), this conversion process is notably limited in humans.[2] Nevertheless, ALA itself, along with its metabolites, plays significant roles in human nutrition and physiology.[1] It is a structural component of cell membranes and is involved in various signaling pathways.

Found predominantly in plant-based foods, ALA is abundant in certain vegetable oils (flaxseed, canola, soybean), nuts (walnuts), and seeds (flax, chia, hemp).[1] Its presence in common dietary components makes it the most prevalent omega-3 fatty acid in many Western diets.[17] Chemically, ALA is identified by the Chemical Abstracts Service (CAS) number 463-40-1 and the DrugBank identifier DB00132.[1] Its molecular formula is C18​H30​O2​.[1] This report provides a comprehensive overview of the chemical properties, metabolism, dietary sources, physiological functions, health effects, safety considerations, and dietary recommendations pertaining to alpha-linolenic acid.

II. Chemical Properties and Structure