Which foods are high in omega-3?
Oily fish, such as salmon, herring, sardines and mackerel. Tuna doesn’t count as oily fish. And chia’s omega-3 is a different kind. Your body makes only a little fish omega-3 from it.
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Which foods are highest in omega-3?
Oily fish, for the kind found in fish. The NHS says they’re the richest source of long-chain omega-3, which can help to prevent heart disease.
Fish gives you two kinds, called EPA and DHA. Salmon and herring top the list.
| Food (85 g serving, or 1 egg) | EPA + DHA (g) | Oily fish in UK advice? |
|---|---|---|
| Salmon, farmed | 1.83 | Yes |
| Herring | 1.71 | Yes |
| Salmon, wild | 1.57 | Yes |
| Sardines, canned | 1.19 | Yes |
| Mackerel | 1.02 | Yes |
| Pink salmon, canned | 0.91 | Yes |
| Rainbow trout, wild | 0.84 | Yes |
| Tuna, canned light | 0.19 | No |
| Tuna, yellowfin | 0.10 | No |
| Egg, one | 0.03 | Not a fish |
Sources: NIH ODS (US data); NHS
Salmon? In these US figures, farmed has a little more than wild: 1.83 g against 1.57 g. Farmed fish usually do, but it depends on what they’re fed.
These are US figures for an 85 g serving. A UK portion is about 140 g cooked, so a portion holds more.
Tins count too. The BHF says fresh, frozen or tinned oily fish are all suitable. Put one on this week’s shopping list.
Which fish count as oily in the UK?
| Type | Examples | Omega-3 |
|---|---|---|
| Oily fish | Herring and kippers, pilchards, salmon, sardines, sprats, trout, mackerel | The richest source. |
| Also oily, says the BHF | Whitebait, carp, eel, anchovies | Counts as oily. |
| Tuna | Fresh or canned | Doesn’t count as oily. |
| Shellfish | Oysters and crab are the main sources | Some, but less than oily fish. |
| White fish | Cod, haddock, pollock | Some contain it, but less than oily fish. |
So tuna is the surprise here. Tinned light tuna has about a tenth of the EPA and DHA in farmed salmon, weight for weight.
Watch the salt. The BHF says to limit smoked or salted fish, and fish tinned in brine. Smoked salmon and tinned anchovies can be high in salt.
Pick tins in spring water or tomato sauce, not brine.
Are chia seeds and flax as good as fish?
Not as a straight swap. Seeds can hold more omega-3 than fish by weight, but it’s a different kind. That different kind of omega-3 is called ALA.
ALA is in some nuts and seeds, and the oils made from them.
Your body can turn some ALA into EPA and DHA, but only in small amounts. A US fact sheet puts the rate at less than 15%.
| Food | Serving | ALA (g) |
|---|---|---|
| Flaxseed (linseed) oil | 1 tbsp | 7.26 |
| Chia seeds | 28 g | 5.06 |
| Walnuts | 28 g | 2.57 |
| Whole flaxseed | 1 tbsp | 2.35 |
| Rapeseed oil | 1 tbsp | 1.28 |
Source: NIH ODS (US data)
Think of ALA as money at a poor exchange rate. You hand over a lot and get back a little. So 5 g of ALA from chia isn’t 5 g of fish omega-3.
Don’t eat fish? The BHF suggests walnuts on porridge, or chia and flaxseed with yoghurt, and rapeseed oil for cooking.
The BHF says algae oil supplements with EPA and DHA are also sold. Algae are tiny water plants. Check the label, as the amount varies.
Plant-based? See blood tests for vegans and plant protein.
What about omega-3 eggs, olive oil and avocado?
An ordinary egg has about 0.03 g of DHA. Some brands of eggs, milk, yoghurt, bread and spreads have omega-3 added, so check the label.
The label words have rules. A “source of omega-3” food needs at least 0.3 g ALA, or 40 mg EPA plus DHA, per 100 g and per 100 kcal.
A “high in omega-3” food needs double. That’s 0.6 g ALA or 80 mg EPA plus DHA.
Olive oil and avocado are mostly a different healthy fat, called monounsaturated fat, not omega-3. Per 100 g, olive oil has under 1 g of ALA and avocado about 0.1 g. Neither has any EPA or DHA.
They’re still good fats. The NHS says monounsaturated fats help protect your heart.
Want some omega-3 in your cooking oil? Use rapeseed oil.
How much oily fish should I eat?
A week of fish, the NHS way
- Eat at least 2 portions of fish a week, and make 1 of them oily.
- Count a portion as about 140 g cooked.
- Girls, and women who may have a child one day or are pregnant or breastfeeding: have no more than 2 portions of oily fish a week.
- Boys and men: have up to 4 portions of oily fish a week.
- Pregnant or trying for a baby: skip shark, swordfish and marlin, and have no more than 4 medium cans of tuna (about 140 g drained) or 2 tuna steaks (140 g cooked) a week.
- Under 16: skip shark, swordfish and marlin. Other adults: no more than 1 portion of these a week.
Source: NHS: fish and shellfish
Short on ideas? The BHF suggests sardines on toast, tinned salmon on a salad or grilled mackerel with pasta.
There’s no UK target for omega-3 itself. The BHF says roughly 450 mg a day is what you’d get from the fish advice.
Thinking of a capsule instead? The BDA says omega-3 supplements aren’t recommended for the general UK population, as evidence of benefit is inconclusive.
Fish liver oils are high in vitamin A. Have no more than 1.5 mg of vitamin A a day from food and supplements combined. See cod liver oil vs fish oil.
On fish oil to lower a blood fat called triglycerides? Read cholesterol results on fish oil.
Curious about your level? See the omega-3 blood test.
When to speak to a GP
Get help if:
- Call 999 if your lips, mouth, throat or tongue suddenly swell, or your throat feels tight. Call too if you’re breathing very fast, or struggling to breathe or swallow. The same goes if your skin, tongue or lips turn blue, grey or pale, or you suddenly feel very confused, drowsy or dizzy. Call if someone faints and can’t be woken, or a child is floppy or not responding like normal. If you have an adrenaline pen, use it first, then call 999.
- You think you or your child may have a food allergy. Fish and shellfish allergies are quite common, says the NHS. Eggs, walnuts, soya and shellfish such as crab are among the most common.
- You’re pregnant or trying for a baby and want fish liver oil. The NHS says to avoid it unless your GP advises otherwise.
- You take medicines that affect blood clotting and want a fish oil supplement. The BHF says to talk to your doctor first.
Never stop or change a prescribed medicine without your prescriber.