Most people know they should eat more fatty fish. But what actually happens in your body when you do — and what goes wrong when you don't? Omega-3 fatty acids are essential nutrients that your body cannot produce on its own. You have to get them entirely from food or supplements.
Key takeaways
- EPA and DHA are the omega-3 fatty acids with the strongest scientific evidence — found primarily in fatty fish.
- The Dutch Health Council recommends 200 mg EPA/DHA per day, equivalent to eating fatty fish once a week on average.
- Plant-based ALA (from flaxseed, chia, walnuts) converts to EPA/DHA at only 5–10% efficiency — not a reliable substitute.
- Algae oil supplements are the best option for non-fish-eaters, as algae are the original source fish get their omega-3 from.
- High-dose supplements above 4 grams EPA/DHA per day carry a risk of heart arrhythmias — stay within safe limits.
What are omega-3 fatty acids?
Three types of omega-3 fatty acids matter for human health:
- ALA (alpha-linolenic acid). The plant-based form, found in flaxseed, chia seeds and walnuts. Your body can partially convert ALA to EPA and DHA, but at a low rate of 5 to 10 percent.
- EPA (eicosapentaenoic acid). Found in fatty fish and shellfish. Plays a role in managing inflammation in the body.
- DHA (docosahexaenoic acid). Also from fatty fish — and the form your brain and eyes need for normal function.
EPA and DHA are where the scientific evidence is strongest. ALA counts toward your omega-3 intake but is not a reliable substitute for the marine fatty acids.
Why does your body need omega-3?
1. Heart and cardiovascular health
Omega-3 fatty acids fit within a healthy dietary pattern and may contribute to heart and blood vessel health. They can help lower triglyceride levels in the blood — a risk factor for cardiovascular disease, according to the Voedingscentrum.
2. Brain function and vision
DHA is required for normal brain function and normal vision. This is especially important during pregnancy: adequate DHA may contribute to brain development and retina growth in the unborn child.
3. Pregnancy outcomes
Getting enough marine omega-3 fatty acids during pregnancy may reduce the risk of preterm birth, according to Dutch dietary guidelines.
How much omega-3 do you need per day?
The Dutch Health Council recommends 200 mg of EPA and DHA per day for adults. In practice, that means eating fatty fish on average once a week.
How much do common fish provide per 100 grams?
- Herring: approximately 2.2 grams EPA + DHA
- Mackerel: 0.4 to 1.85 grams
- Salmon: 0.8 to 2.2 grams (depending on wild or farmed)
Want to know more about salmon as a nutritional powerhouse? Read our salmon nutrition guide.
Plant-based omega-3 sources
If you don't eat fish, you can get ALA from:
- Flaxseed and flaxseed oil — the richest plant source
- Chia seeds — easy to add to yoghurt or oatmeal
- Walnuts — a small handful contributes meaningfully
- Hemp seeds — less well-known but with a good omega-3 profile
The conversion problem remains: only a small fraction of ALA becomes EPA or DHA. Algae oil supplements bypass this entirely — algae are the original source that fish accumulate omega-3 from. For vegans and vegetarians, algae oil is the most reliable option.
Omega-3 supplements: when do they make sense?
Supplements can be a sensible choice if you consistently don't eat fish. Look for products with clearly stated EPA and DHA content on the label — not just total omega-3.
One important safety note: doses above 4 grams of EPA and DHA per day increase the risk of heart rhythm disturbances, according to EFSA. For most healthy adults who eat fish regularly, supplements are not necessary.
Omega-3 vs. omega-6: the ratio matters
Most people in Western countries eat far too much omega-6 (from sunflower oil, processed foods, ready meals) relative to omega-3. Both fatty acids compete for the same enzymes in your body. A heavily skewed ratio may promote inflammatory processes. You don't need to avoid omega-6 — just consciously include more omega-3-rich foods.
Curious about the other end of the fat spectrum? Read our guides on saturated fats and trans fats — the fats most worth limiting.
Start getting more omega-3 today
Eating herring or mackerel once a week is all it takes to meet the Health Council's recommendation. That's one portion — not a major lifestyle overhaul.
Moveno tracks EPA and DHA separately in your daily nutrition overview, so you always know where you stand without spreadsheets or guesswork.
Sources
- Voedingscentrum — Omega 3 — Dutch dietary guidelines for omega-3, sources and recommendations
- Voedingscentrum — Omega-3 benefits during pregnancy — specific recommendations for pregnant women
- EFSA — Safety assessment of long-chain omega-3 fatty acids — upper safety limit of 4 grams EPA/DHA per day
