It’s a timely question as tinned fish is enjoying a renaissance not seen since the days of Victorian exploration. Those of you with your finger on the digital pulse can’t have failed to have notice hashtags like #tinnedfish and #tinnedfishnight accompanied by fish paired with some fancy charcuterie-style spread.
Part of its phoenix-from-the-flames appeal is similar to the craft-ale explosion, namely that some of the artwork selling said fish is almost collectible. The other is that tinned fish is both nutrient-dense and affordable.
How healthy is tinned fish?
Well, it's extremely nutrient-dense. Tinned fish such as sardines contain a matrix of cardioprotective nutrients including omega-3s. They also contain potassium, magnesium, zinc, iron and arginine that together dampen inflammation and cut the chances of heart disease.
Are sardines better than tinned staples such as mackerel, herring, anchovies and tuna? Their nutritional profile is pretty similar, with one can of sardines providing 200 calories of which 22g derives from muscle-building protein and 12g from good fats, plus a host of vitamins. Mackerel, herring and anchovies are in the nutritional ballpark, albeit anchovies possess higher levels of sodium. Hence, their rather alluring salty, seadog taste. Each contains edible bones that crank up bone-strengthening calcium. Tuna’s also high in protein and omega-3s, though this is one fish to be particular about due to environmental and mercury reasons, which we’ll come back to.
Is fish preserved in olive oil best?
What potentially impacts its health profile is what the fish is preserved in. You should avoid sunflower oil and those packed with added sugars as that just scars you with empty, unforgiving calories. Soybean isn’t great either due to high levels of omega-6 that can have negative effects on health if eaten to excess. Instead, fish packed in spring water or healthy olive oil is the ideal. The latter naturally adds calories, albeit from good fats.
Brine tows the line between good and bad. It preserves the fish without the need for artificial preservatives and is lower in calories than oil. On the downside, most brine-packed fish is high in salt, which can contribute to high blood pressure and raise the risk of heart disease. That said, there are tinned fish preserved in low-sodium brine.
Which is healthier – fresh fish or tinned fish?
As for the debate whether fresh or tinned fish is healthiest, that depends. Fresh fish, like mackerel, is deemed to contain higher levels of omega-3 than its tinned sibling, which endures minimal losses during the canning process. However, fresh is deemed best only if eaten raw or lightly cooked. The canning process also reduces levels of certain heat-sensitive nutrients like vitamins C and some B vitamins.
The USDA suggest that fresh and tinned fish have roughly the same nutritional value, though the latter is often higher in sodium. It is, however, more convenient, which is exactly what pleased the seafaring explorers back in the day.
That nutritional value is supported by a wealth of studies into fish’s health-boosting properties, including a 2002 French study, which revealed that of the 1,674 elderly residents they’d followed for seven years, studying their consumption of meat versus seafood, those who ate fish (including tinned fish) at least once a week had a significantly lower chance of developing dementia.
What about tuna?
Unfortunately, it’s not all good news due to mercury, which is found in all fish and naturally accumulates from the environment. It’s highest the further a fish swims in the food chain, which is why tinned tuna hit the headlines in 2024 when a report by Bloom, a marine conservation organisation based in France, warned of the high mercury levels found in tinned tuna. The main concern, the report read, is methylmercury, which is a toxin that builds up in fish and shellfish and in high levels in humans can harm the brain and nervous system.
It's why in Britain we have a maximum level of mercury for tuna and “other specified species” capped at 1mg/kg. A business is responsible for adhering to these limits and products should be removed from the shelves if exceeded. To that end, the government say, “We have no evidence that tinned tuna is unsafe to eat.”
That said, the general advice is that if you’re pregnant, breastfeeding or feeding young children, you should stick to low-mercury tinned fish such as sardines, salmon and light tuna (which is mostly skipjack), and avoid white tuna (or albacore). All in all, for most healthy adults, two to three portions of fresh or tinned fish each week is the ideal.
Finally, when it comes to sustainability, there are several certifications and labels to look out for. MSC (Marine Stewardship Council), a blue eco-label, means the fishery is independently certified as sustainable and well-manged, while ASC (Aquaculture Stewardship Council) certification, says the ASC, “assures seafood lovers that their seafood has been farmed with care”. If it’s Fair Trade Certified, that means better environmental and labour practices.
Ideally, the label will flag up that it’s been pole and line caught, which is much better for the species and the environment than trawling methods. Ultimately, brands that share full supply chain information – even a QR code you can scan – are generally the most trustworthy.
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Top image: an illustration of tinned fish. Credit: Getty
