Tinned fish is a convenient source of protein that can boost your diet at a fraction of the cost of poultry, meat and fresh fish.
Some varieties are also packed with omega-3 essential fatty acids (EFAs), which we know to be vital for lowering ‘bad’ cholesterol and supporting brain health.
But how do you know what type of tinned fish to choose for the best? We painstakingly picked our way through more than 90 products* to find those with the highest omega-3 levels, and uncovered benefits – and some of the pitfalls along the way.
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Tinned oily fish contains high-quality protein, vitamins (including D and B12), calcium (from the edible bones of some canned varieties), and is a rich source of omega-3 essential fatty acids (EFAs).
Omega-3 EFAs are a family of polyunsaturated fatty acids comprising three types, including the two in oily fish – EPA and DHA. The other, ALA, is found in plant foods such as flaxseed.
EPA and DHA are important for heart, lung, blood vessel health, hormone and immune system health. Neither can be made by the body so you need them in your diet.
The Food Standards Agency (FSA) recommends that most people eat two portions of fish per week, with a portion size of around 140g (cooked weight), and one of these portions should be oily fish, as they contain beneficial long-chain omega-3 fatty acids.
If you’re a man or an older woman, you’re actually allowed up to four 140g portions of oily fish per week. Still, younger, pregnant and breastfeeding women shouldn’t have more than two oily fish portions a week because fat-soluble contaminants found in them, like dioxins and PCBs, may impact a developing foetus.
There’s no UK government recommendation for omega-3s, but a single weekly oily fish portion will give you the equivalent of around 450mg of combined EPA and DHA per day. However, research shows that much of the UK population consumes less than 50mg of omega-3 fatty acids per day, and only 16-17% meet the weekly oily fish recommendation.
A concern when eating fish may be mercury because fish consume plankton that produce methylmercury. However, scientific testing reveals that, due to their short lifespan and low position in the food chain, small oily fish such as sardines, mackerel, pilchards, and even salmon are very low in mercury.
Higher levels are found in swordfish, shark and fresh tuna, which is why the FSA suggests limiting consumption. Although mercury levels in canned tuna are lower because ‘skipjacks’ are younger, smaller fish, pregnant women should limit their consumption to no more than four cans per week.
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Starting with the most abundant, mackerel, sardines, and salmon officially have the highest levels of omega-3s of all the tinned fish. While our market analysis of more than 90 products reflected this general pattern, there was a wide variation within each fish type and from one brand and recipe to the next.
For example, Princes skinless boneless wild red salmon has 900mg of omega-3 per 100g compared to Sainsbury’s skinless boneless wild Pacific red salmon, which has almost double that at 1,600mg per 100g.
Kippers, skippers, brisling, sild and sprats (all types of herring) plus pilchards (older, larger sardines) are other good choices for omega-3 you can find in the tinned fish aisle.
Tinned anchovies are also classified as oily fish, but are often high in salt, so use them sparingly.
Tinned crab contains omega-3s; the amounts are low, so it doesn’t count as one of your oily fish portions.
As for tinned tuna, being cooked before canning drastically reduces omega-3 levels, although some are still present, but not at the levels found in other tins tested.
Others that weren’t far behind include Tesco Finest smoked peppered mackerel, 3640mg omega-3 per 100g (£3 for 110g tin, Tesco)
The tinned mackerel product with the lowest levels that we looked at was Princes spicy tomato jack mackerel fillets, containing 700g omega-3 per 100g – just over seven times less than the most abundant mackerel product.
Note: The Waitrose No.1 peppered mackerel also has the highest salt content that we found, so bear this in mind if you’re watching your sodium levels.
The tinned sardine product with the lowest omega-3 levels we looked at was Alva sardines in tomato sauce, which had 940mg omega-3 per 100g – just under 4.5 times less than the most abundant sardine product.
The tinned salmon with the lowest omega-3 levels that we looked at was Waitrose boneless wild red salmon, which had 444mg omega-3s per 100g – almost five times less than the most abundant salmon product.
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We also scrutinised the salt and sugar levels of the 90+ tinned fish products, as well as how much they cost – here are some highlights:
When it comes to salt, adults should have no more than 6g (1 level tsp) daily, including salt that’s already in food as well as that added during and after cooking.
The saltiest tinned fish we found – Waitrose No.1 peppered mackerel – has 2.21g of salt per 100g – 22 times more than the least salty product – and a recommended 70g serving contains 1.55g of salt – that would be a quarter of your daily maximum.
In total, just five of the 90 products we examined contained 0.3g of salt or less per 100g, which is the official threshold for a food to get a green traffic light for salt.
When it came to sugar, the tinned fish with the most had 12g per 100g, while the vast majority were in the low-sugar range (5g or less per 100g), with around one-third containing no sugar.
However, although 12g tops the list for the most sugar, this amount is still considered ‘moderate’ for sugar (high would be more than 22.5g per 100g). Some products get it from natural sugars (eg those that contain tomato paste) while others have added sugar such as demerara.
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Neither tinned nor fresh fish is intrinsically ‘better’ – both have advantages and disadvantages relating to factors such as cost, shelf life, sustainability and nutritional content.
Tinned fish tends to be a cheaper, easier to store and a more sustainable choice, plus natural omega-3 oils are preserved by the canning process.
Fresh fish is expensive, but you’re paying for its flavour, texture, and a product without any added ingredients or processing. Ultimately, it comes down to personal preference.
A 2024 large-scale UK analysis found that fish oil supplements can be effective at boosting blood omega-3 levels, which may be music to the ears of those who struggle with their fish intake.
However, omega-3 supplements aren’t recommended in the general population because evidence of benefits is inconclusive. They are also contraindicated in some people, including those on blood thinners such as warfarin, plus they can be high in vitamin A, which can be toxic in large amounts. Speak to your doctor if you’re unsure.
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Fish in brine doesn’t always have the highest salt levels. Intuition might tell you that fish in salt water will be highest in salt, but we found that some of the highest levels in flavoured sauce varieties. For example, Morrisons mackerel fillets in brine have 0.77g of salt per 100g while Morrisons mackerel fillets in smokey BBQ sauce contain 1.52g salt per 100g.
Choose tomato sauce rather than ‘spicy’ tomato sauce. Fish varieties in plain tomato sauce, in the main, have natural sugars in them, but we found that those in ‘spicy’ tomato sauce had added sugar – in some cases more than double the amount. For example, Tesco mackerel in tomato sauce has 2g of sugar per 100g compared to Tesco mackerel in spicy tomato sauce, which has 4.8g.
Don’t worry if you can’t find omega-3 levels on packaging. It’s not a legal requirement to declare omega-3s in the UK and EU, unless a specific health claim is made (eg ‘High in omega-3’). However, stick with tinned mackerel, sardines, or salmon, and you can rest assured that you’ll be getting omega-3 essential fats.
