Conversion of ALA to EPA and DHA
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are absorbed, on the one hand, through the consumption of fish and algae. On the other hand, alpha-linolenic acid (ALA) is the substrate for the formation of EPA and DHA, and 10% of ALA ingested through vegetable oils is enzymatically converted to EPA and DHA.
Anti-inflammatory (anti-inflammatory) activity
Alpha-linolenic acid attenuates inflammatory responses. When ALA is ingested, as well as linolenic acid (LA), these two fatty acids compete for the same enzymes of elongation and desaturation, such as Δ-6-desaturase and Δ-5-desaturase. In addition to DHA, EPA is formed from alpha-linolenic acid. Series-3 eicosanoids, which have anti-inflammatory (anti-inflammatory) effects, are formed from this omega-3 fatty acid. LA is converted under enzymatic influence into arachidonic acid, from which the series-2 eicosanoids are formed. These have an inflammatory effect. ALA has an anti-inflammatory effect because the enzymes prefer this omega-3 fatty acid compared to LA. Thus, the fatty acids of the linoleic acid series are displaced from the enzyme binding sites and preference is given to EPA and series-3 eicosanoids. ALA thus decreases the synthesis of series-2 eicosanoids.
Role in cell membrane
ALA and its derivatives DHA as well as EPA play an important role in cell membranes as structural elements of phospholipids. They enable cell membrane elasticity and thus ensure good nutrient and oxygen supply. DHA in particular belongs to the structural lipids of the nervous system and is a component in the photoreceptors (specialized, light-sensitive sensory cells) of the retina (retina of the eye). During pregnancy and lactation, DHA promotes the development of the brain, central nervous system, and vision of the child.
Effect on cardiovascular system
A meta-analysis of 27 studies concluded that increased ALA intake moderately reduced cardiovascular risk. However, the study designs of the different trials were very heterogeneous, so this effect needs to be analyzed in future intervention studies. Other reviews also conclude that ALA intake (approximately 2 to 3 g/day) contributes to the prevention of cardiovascular disease.