What Are Omega-3 Fatty Acids?
Omega-3s are a family of polyunsaturated fats essential for human health — meaning your body cannot produce them, so you must obtain them through diet. The three main types are:
- EPA (eicosapentaenoic acid): Found primarily in fatty fish; has strong anti-inflammatory effects
- DHA (docosahexaenoic acid): Found primarily in fatty fish; critical for brain and eye development and function
- ALA (alpha-linolenic acid): Found in plant foods (flaxseed, walnuts, chia seeds); the body converts a small amount to EPA and DHA (less than 10% efficiency)
Evidence-Based Benefits
| Health area | Evidence |
|---|---|
| Cardiovascular health | Strong — reduces triglycerides, may lower blood pressure and inflammation |
| Brain health | Strong — DHA is 40% of brain fatty acids; associated with cognitive protection |
| Depression | Moderate — meta-analyses show benefit, especially EPA-rich supplements |
| Inflammation | Strong — EPA/DHA reduce inflammatory markers (CRP, IL-6) |
| Eye health | Moderate — DHA is 60% of retinal fatty acids |
| Pregnancy | Strong — DHA critical for fetal brain and eye development |
Recommended daily omega-3 intake:
EPA + DHA combined: 250–500mg/day (general health)
EPA + DHA: 1,000–2,000mg/day (cardiovascular protection)
ALA (plant-based): 1.6g/day (men), 1.1g/day (women)
EPA + DHA combined: 250–500mg/day (general health)
EPA + DHA: 1,000–2,000mg/day (cardiovascular protection)
ALA (plant-based): 1.6g/day (men), 1.1g/day (women)
Best Food Sources
| Food | EPA + DHA per serving |
|---|---|
| Salmon (100g) | ~2,000mg |
| Mackerel (100g) | ~2,500mg |
| Sardines (100g) | ~1,500mg |
| Herring (100g) | ~1,800mg |
| Walnuts (30g) | ~2,500mg ALA only |
| Flaxseed (15g) | ~3,200mg ALA only |
Frequently Asked Questions
Do I need omega-3 supplements?If you eat 2+ servings of fatty fish per week, supplements are generally unnecessary. Vegetarians and vegans, people who dislike fish, and those with cardiovascular risk factors benefit most from supplementation. Algae-based DHA/EPA is the best plant-based alternative.
Do omega-3s help with weight loss?Modestly. Omega-3s improve insulin sensitivity and may slightly reduce appetite through hormonal effects. They're not a weight loss supplement, but they support the metabolic environment that makes fat loss easier.