Omega-3-Fettsäuren Physiologische Funktionen und gesundheitliche Wirkungen – derzeitiger Stand der Diskussion

Omega-3 fatty acids (n-3 FAs), particularly the long-chain n-3 FAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are involved in numerous biochemical processes and are therefore of central importance for a wide range of physiological functions. They influence membrane fluidity, exert anti-inflammatory effects, and modulate cardiovascular, neuronal, and immunological functions. In a strict nutritional sense, only α-linolenic acid (ALA) is considered essential, as it cannot be synthesized by the human body and must be obtained from the diet. Although EPA and DHA can in principle be synthesized endogenously from ALA, conversion rates are very low; consequently, there is increasing discussion that these fatty acids should also be provided in sufficient amounts through the diet. While observational studies largely indicate that an adequate EPA and DHA status is associated with a lower risk of cardiovascular disease, neurocognitive impairment, and preterm birth, results from randomized controlled trials are heterogeneous. This inconsistency is mainly attributable to the fact that outcome assessments often fail to adequately account for baseline omega-3 status, despite its substantial influence on observed effects. To improve omega-3 supply, EPA and DHA are available from various sources and in different chemical forms, all of which are suitable for ensuring adequate long-term status. In Germany, dietary intake of ALA is sufficient, whereas intake of EPA and DHA is inadequate; the mean Omega-3 Index ranges from 5.3–5.8%, which is below the recommended target value of ≥ 8%. The German Nutrition Society (DGE) recommends the consumption of at least one portion of fatty sea fish per week, whereas international expert societies advise an intake of ≥ 500 mg EPA + DHA per day. Intakes of n-3 FAs up to 5 g/day are considered safe; however, at very high doses, a slight increase in the risk of atrial fibrillation has been reported. Given the relevance of EPA and DHA for cardiometabolic and neuronal health, there is a clear need for targeted strategies to improve EPA/DHA status.