Omega-3 Fatty Acids: Benefits, Dosage and Best Sources
Omega-3 fatty acids EPA, DHA and ALA: scientific mechanisms of action, optimal dosage, best food sources, and who benefits from supplementation.
What Are Omega-3 Fatty Acids?
Omega-3 fatty acids are polyunsaturated fatty acids (PUFAs) that the human body cannot synthesize on its own — making them essential nutrients that must be obtained through diet. The three most important omega-3 forms are:
- ALA (Alpha-Linolenic Acid): Plant-based (flaxseed, walnuts, chia). The body can only inefficiently convert ALA to EPA and DHA (conversion rate < 10%).
- EPA (Eicosapentaenoic Acid): Marine fatty acid from fatty fish. Strongly anti-inflammatory.
- DHA (Docosahexaenoic Acid): Marine fatty acid. Primary structural component of the brain (30% of fatty acids in neuron membranes) and retina.
Biochemical Mechanisms of Action
Anti-Inflammatory Effects
EPA and DHA compete with arachidonic acid (Omega-6) for cyclooxygenase and lipoxygenase enzymes. This produces fewer pro-inflammatory eicosanoids (series 2 and 4 prostaglandins and leukotrienes) and more anti-inflammatory resolvins and protectins.
Practical implication: a favorable Omega-3/Omega-6 ratio (target: < 1:5, Western diet often 1:15) reduces chronic inflammatory load.
Cardiovascular Benefits
- Triglyceride reduction: EPA/DHA lower triglycerides by 15–30% (from 2 g/day)
- Blood pressure reduction: moderate antihypertensive effect (systolic approx. −2 mmHg)
- Anti-atherogenic: stabilization of atherosclerotic plaques
- Antiarrhythmic: DHA alters ion channel kinetics in cardiomyocytes
Brain and Cognition
DHA is the most important structural fatty acid in the CNS. Adequate DHA supply is associated with:
- Better cognitive function in aging
- Reduced risk of depression (meta-analyses show effect with > 1 g EPA/day)
- Neuroprotective effects in neurodegenerative diseases
Optimal Intake and Sources
Recommended Daily Intake:
- ALA: 0.5% of total energy (approx. 1.5–2.5 g/day)
- EPA + DHA: At least 250–500 mg/day
- Therapeutic (e.g., triglyceride reduction): 2–4 g EPA/DHA daily
Best Food Sources (EPA + DHA per 100 g):
| Food | EPA + DHA | |---|---| | Herring | 2,100 mg | | Mackerel | 2,000 mg | | Wild Salmon | 1,800 mg | | Sardines | 1,500 mg | | Tuna | 900 mg | | Trout | 700 mg |
Plant-based ALA sources:
- Flaxseed oil: 53 g ALA/100 ml
- Chia seeds: 17.5 g/100 g
- Walnuts: 9 g/100 g
- Rapeseed oil: 9 g/100 ml
Supplementation: When Is It Beneficial?
With fish consumption < 1–2 portions/week, vegan diet, or increased need (pregnancy, heart disease, inflammatory conditions), supplementation is advisable. Algae oil preparations (EPA + DHA from microalgae) are a valid vegan alternative.
Conclusion
Omega-3 fatty acids are among the best-researched nutrients with a broad spectrum of effects. Nutrion analyzes your current fatty acid supply and gives evidence-based recommendations for diet and supplementation.