Are Britons low in omega-3? What UK diet data and NHS advice show

The NHS asks us to eat at least one portion of oily fish a week. The UK's own diet survey shows most adults eat well under half of that. Here's what the national data says about omega-3 in Britain, how we compare with the rest of Europe, which fish actually count, and how to find out where you stand.

What the UK is advised to eat

NHS advice, based on the Scientific Advisory Committee on Nutrition (SACN), is to eat at least two portions of fish a week, one of which should be oily. A portion is about 140 g cooked. SACN estimated that following this advice provides roughly 450 mg of the long-chain omega-3s EPA and DHA a day, averaged over the week.

There are sensible upper limits too. The NHS suggests no more than two portions of oily fish a week if you're pregnant, planning a pregnancy or could become pregnant (and for girls), and no more than four a week for everyone else, because oily fish can carry low levels of pollutants.

What Britons actually eat

The National Diet and Nutrition Survey (NDNS), the government's rolling survey of what people in the UK eat, found that average oily fish intake was the equivalent of about 56 g a week for adults aged 19–64 and 86 g a week for those aged 65 and over (Years 9–11, 2016–2019). That is well under the single 140 g portion recommended, in every age group. Children averaged less than 20 g a week.

Averages also hide a lot: many adults eat no oily fish at all in a typical week, while a minority eat plenty.

Which fish count (and which don't)

• Oily fish: mackerel, herring and kippers, sardines and pilchards, salmon, trout, sprats and fresh anchovies.
• White fish: cod, haddock, plaice, pollock and coley. Healthy, but much lower in EPA and DHA. A Friday fish supper is usually cod or haddock, so it doesn't count as your oily portion.
• Tuna: the NHS doesn't class fresh or tinned tuna as oily fish.

Our omega-3 in seafood table shows how far apart the numbers are.

How the UK compares with the rest of Europe

Advice across Europe is broadly similar. The European Food Safety Authority (EFSA) sets an adequate intake of 250 mg EPA + DHA a day for adults; the UK's two-portions advice works out higher, at around 450 mg. What differs is what people eat.

A global survey of blood omega-3 levels (Stark et al., 2016) found high levels in populations that eat a lot of seafood, such as Japan and parts of Scandinavia, while the UK sat among the low-to-very-low countries along with much of Western Europe and North America. Britain is an island nation, but at the dinner table it behaves like an inland one.

Why the gap matters

The British Heart Foundation includes oily fish as part of a heart-healthy, Mediterranean-style diet, and higher omega-3 blood levels have been linked with better heart health in observational studies. That evidence shows association, not proof that omega-3 prevents disease, and NICE does not recommend omega-3 supplements to prevent heart disease. Our article on omega-3 and heart health in the UK goes through what the guidance does and doesn't say.

A supplement doesn't guarantee you've closed the gap

Supplements vary widely in how much EPA and DHA they contain, and people absorb them differently, so two people on the same capsule can end up at very different levels. If you're deciding between capsules, see algae oil vs fish oil.

How to find your own number

The Omega-3 Index measures EPA + DHA as a percentage of your red blood cell fats, reflecting the last three to four months. Research proposes 8–12% as the optimal range. It isn't part of routine NHS blood tests (see can you get an Omega-3 Index test on the NHS?), but you can do it at home with a finger-prick kit, no GP referral needed.

The Omega-3 Index Basic test is £49.95 with free standard UK delivery, and new customers can use OMEGA10 for 10% off a first order. When your result arrives, our UK guide to reading it walks through what to do next.

Frequently asked questions

Does fish and chips count as oily fish?

Usually not. Chip-shop fish is normally cod or haddock, which are white fish and much lower in EPA and DHA.

Is tinned tuna oily fish?

The NHS doesn't count tuna, fresh or tinned, as oily fish. Tinned sardines, pilchards and mackerel do count.

How much oily fish is safe in pregnancy?

The NHS advises up to two portions of oily fish a week in pregnancy. See omega-3 in pregnancy and why cod liver oil isn't advised.

Can I get an omega-3 test on the NHS?

The Omega-3 Index isn't part of routine NHS blood tests, so most people use an at-home test.

References

1. NHS. Fish and shellfish (Eat well). nhs.uk.
2. Scientific Advisory Committee on Nutrition / Committee on Toxicity. Advice on fish consumption: benefits and risks. 2004.
3. Public Health England / Food Standards Agency. National Diet and Nutrition Survey Rolling Programme Years 9 to 11 (2016/2017 to 2018/2019). 2020.
4. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on Dietary Reference Values for fats. EFSA Journal 2010;8(3):1461.
5. Stark KD, Van Elswyk ME, Higgins MR, et al. Global survey of the omega-3 fatty acids in the blood of healthy adults. Progress in Lipid Research. 2016;63:132–152.
6. NICE. Cardiovascular disease: risk assessment and reduction, including lipid modification (NG238). 2023.
7. British Heart Foundation. Oily fish and heart health guidance.

This article is general information, not medical advice, and the test is not a diagnostic test. Talk to your GP before making significant changes to your diet, supplements or medication, especially in pregnancy.