Tinned sardines have seen an explosion in popularity in recent years. UK sardine sales went up by around 30% in a year, and some smaller tinned-fish brands say their sales have more than doubled.
In our opinion, part of this is because they’re delicious, they’re ready to eat and a handy cupboard staple for a quick meal, like our tinned sardine puttanesca. But Instagram and TikTok are also full of claims about how good sardines are for you, and whilst some of those claims stand up, others, like “sardine fasts” for rapid weight loss, have limited research behind them.
The idea that oily fish is good for you isn’t new. The NHS recommends eating at least two portions of fish a week (a portion is about 140g), and one of those should be an oily fish, such as sardines. However, most of us don’t manage it. On average, UK adults eat just 56g of oily fish a week, which is less than half a portion.
So, do they live up to the hype? Here, we dig into the science behind sardines and their health claims.
Why are sardines good for you?
The many benefits of omega-3 fatty acids
Omega-3 polyunsaturated fatty acids are a type of healthy fat. The two that matter most, EPA and DHA, are found mainly in oily fish, and since our bodies can’t make enough of them on their own, we need to get them from food, and sardines are one of the best sources.
Some lab tests put sardines at around 1g of EPA and DHA per 100g, whereas independent testing of tins in the UK showed some tins have much, much more. Which? looked at more than 90 tinned fish products, and the sardines ranged from 940mg to 4,200mg of omega-3 per 100g, depending on the brand.
UK experts recommend consuming about 450mg of EPA and DHA a day, or roughly 3g a week. Tin dependent, this means one tin provides you with a quarter of the weekly amount on the lowest end, but many tins realistically provide you with the full recommended amount or more.
Heart health
Omega-3s are best known for their contribution to heart health. They lower triglycerides (a type of fat in the blood that raises the risk of heart disease at high levels), can reduce blood pressure, and help calm inflammation in the body. The American Heart Association says that people who eat fish once or twice a week are less likely to die of heart problems, have heart disease, have the most common type of stroke or develop heart failure.
Interestingly, the evidence suggests that the benefits of omega-3s come from eating food with omega-3s, rather than supplementation, and the advice in the UK is not to take omega-3 supplements unless told to do so by your doctor. One reason may be that sardines give you a whole host of other nutrients, such as calcium, selenium, vitamin D and protein, alongside the omega-3s.
Brain health and mood
A large 2023 meta-analysis (a review bringing together multiple studies) that in total tracked more than 100,000 people over many years. From this, the evidence showed people who ate more omega-3 were around 20% less likely to develop dementia or have problems with memory and thinking as they got older.
Omega-3s may also have a positive impact on mood. There is evidence that omega-3s provide preventative benefits for mood and anxiety disorders. Another review corroborated this, and found the greatest benefits were from EPA (one of the types of omega-3 fatty acids).
Pregnancy
Omega-3s are important during pregnancy too. A review of 70 studies involving nearly 20,000 women found that getting more omega-3s in pregnancy lowered the chance of having a baby early, by 11% for premature births and 42% for very early births. DHA is also one of the building blocks of a baby’s brain and eyes. There is also evidence that omega-3s help the development of the baby’s nervous system, and this goes beyond pregnancy and continues when mothers are breastfeeding.
A slight caveat here, the NHS advises pregnant women, and women trying for a baby, shouldn’t have more than two portions of oily fish a week.
Calcium and vitamin D
Sardines might be cooked before canning or only in the tin, but all tins essentially undergo a process where they are pressure cooked, which softens the bones to the point they melt when eaten, and those bones are packed with calcium. The Royal Osteoporosis Society says half a tin gives you 200mg, so a whole tin provides roughly 400mg. That’s more than half of the 700mg adults need each day, assuming you leave the bones in. If you pick the bones out, you lose most of the calcium. If you’re not keen on the bones, try breaking the sardines up into a sauce, like in our sardine puttanesca recipe, and you won’t notice them.
Sardines, and oily fish more generally, are some of the foods with the highest levels of vitamin D in them, which helps your body absorb and use the calcium found in the fish. A tin gives you about 4 micrograms, around 40% of the recommended amount adults need each day.
It’s also worth paying attention to vitamin D intake if you’re eating a lot less than usual, for example if you’re using weight loss injections like GLP-1s. A large US study found that about one in five people prescribed these medicines were diagnosed with some kind of nutrient shortfall within a year, of which vitamin D deficiency was the most common.
It should be noted that in the UK, the advice is still for everyone to take vitamin D supplements in autumn and winter, when the sun isn’t shining enough for our bodies to make enough.
High in protein
One tin of sardines contains around 22g of protein. Unless you do a lot of hard sport or weightlifting, the UK guideline is 0.75g of protein for every kilogram you weigh, which is about 60g a day for someone who weighs 80kg or 45g for someone who weighs 60kg, so one tin covers from about a third to half the daily requirement.
Protein is important because it:
- Keeps your muscles strong. Protein is what your body uses to repair and maintain muscle. This becomes more important as we get older and naturally start to lose muscle.
- Helps recovery after exercise. Around 20–25g of protein after a workout seems to be ideal for helping muscles recover.
- Keeps you full. Meals high in protein tend to leave you feeling fuller for longer, which is why sardines on toast makes a satisfying lunch.
Iron
Iron helps your blood carry oxygen around your body, and not getting enough can leave you tired, short of breath and at risk of iron-deficiency anaemia. Unfortunately, low iron intake is a common problem in the UK, especially for women. Government figures show that almost half of girls aged 11-18, and a quarter of women aged 19–64, don’t get enough iron in their diet, with almost 1 in 10 girls aged 11-18 showing signs of iron-deficiency anaemia and low iron stores..
Sardines contain about 2.9mg of iron per 100g, and a tin gives you around 2.6mg. That’s about a third of the 8.7mg men need each day and a sixth of the 14.8mg women aged 19–50 need. The iron in fish and meat is also easier for your body to absorb.
Vitamin B12
Sardines are absolutely jam-packed with vitamin B12. They have around 8.9 micrograms per 100g, and adults need just 1.5 micrograms a day, so one tin gives you about five times what you need.
B12 helps your body make red blood cells, keeps your nerves healthy and helps turn food into energy. Not getting enough can make you feel tired and weak, and if the deficiency is prolonged it can also cause problems with your nerves, such as pins and needles, memory problems and poor balance.
As with vitamin D, vitamin B12 intake is worth keeping an eye on if you’re eating less than usual or using weight loss injections like GLP-1s.
Selenium
Sardines provide about 53 micrograms of selenium per 100g, so a tin covers roughly two-thirds of what adults need each day (75 micrograms for men and 60 micrograms for women). Selenium is a mineral that helps protect your cells from damage and supports your immune system and thyroid.
Creatine
Creatine is a natural substance that gives your muscles quick bursts of energy, and it’s a popular supplement for people who lift weights as it’s been shown to improve strength and muscle mass. More recently, research suggests that creatine can also help with memory, mood and brain function.
You may have seen claims online that sardines contain 5g of creatine per 100g, the same as a daily supplement dose. Unfortunately, this one probably isn’t true. Fish contain roughly 3–10g of creatine per kilogram, with herring at the top of the range. The viral figure seems to be a per-kilogram number that has been mistaken for a per-100g one. Cooking also reduces creatine levels.
So, whilst sardines do give you a dose of creatine, it’s not anywhere near the amount that’s being promised by many, so won’t replace a supplement if you’re training to build muscle or improve performance.
Are there any concerns with sardines?
Mercury
Nearly all fish contain some level of mercury, but the good news here is that sardines are one of the lowest mercury fish you can eat. They’re small, don’t live long and feed on plankton rather than other fish, so they don’t build up much mercury. In US government testing, sardines had around 10 times less mercury than tinned tuna, and about 75 times less than swordfish.
The NHS recommends pregnant women, women trying for a baby, women breastfeeding, and girls limit oily fish to two portions a week, and four a week for everyone else, because of other pollutants that can build up in the body over time. Within those limits, the benefits outweigh the risks.
High levels of salt
Tinned sardines can be salty, although this does also make them tasty. Most tinned sardines contain between 0.8g and 1.5g of salt per 100g, which means slightly more for a 120g tin (up to 1.8g for a tin). This is almost a third of your recommended daily salt intake of 6g per day, and excessive salt can raise your blood pressure and increase your risk of heart attacks and strokes.
This means you should be careful how much additional salt you add to meals with tinned sardines, and keep an eye on overall intake over the day. The salt in the sardines and the sauce or liquid it’s packed in can help to season your food.
Gout
Sardines are high in purines, natural substances that your body breaks down into uric acid. Too much uric acid can form sharp crystals in your joints, which is what causes the painful swelling of gout. Sardines contain about 210mg of purines per 100g, which puts them in the “high purine” group of foods (over 200mg per 100g).
If you have gout or have been told your uric acid levels are high, you may not need to cut sardines out, but check with your GP or a dietitian about how much is right for you.
How to choose the healthiest tinned sardines
- Keep the bones in - that’s where the calcium is!
- Check the salt levels and consider how this fits with your meals
- Olive oil or water? Olive oil adds calories but also healthy fats
- Buy the good stuff. Browse our collection of tinned sardines, hand-packed and sustainably sourced from the UK and Portugal, in olive oil, tomato sauce and more.
- Don’t overdo it. Most adults can have up to four portions of oily fish a week, but if you’re pregnant, breastfeeding, trying for a baby, or a girl, have no more than two.
In conclusion, are sardines good for you?
Many of the social media claims about sardines are backed by good science. They’re a cheap, delicious and convenient source of omega-3s, protein, calcium, vitamin D, iron, vitamin B12 and selenium, and they’re low in mercury. But some claims go too far - sardines won’t replace a creatine supplement. For most people, though, a couple of tins a week is an easy way to reach the NHS’s oily fish recommendation.
Ready to stock up? Explore our tinned sardines collection and try them in our quick tinned sardine puttanesca.
Frequently asked questions about sardines
Are tinned sardines as healthy as fresh sardines?
Yes, in most ways. The canning process keeps the omega-3 oils in the fish, and it softens the bones so you can eat them, which makes tinned sardines a much better source of calcium than fresh fillets. The main downside is salt, so keep an eye on that when making your meals.
How many tins of sardines can I eat a week?
The NHS says most adults can eat up to four portions of oily fish a week, with a portion being about 140g. A standard tin holds about 90g of fish (often 120g net weight with liquid or sauce), so that works out at around six tins a week. If you’re pregnant, trying for a baby, breastfeeding, or a girl or young woman, the limit is two portions, or about three tins a week.
Can I eat sardines every day?
A tin a day adds up to around 630g of oily fish a week, which is a little over the NHS limit of four portions (about 560g) for most adults, and well over the limit for pregnant women. But most days of the week is fine for most people, as long as you mix in other protein foods too.
Is it safe to eat the bones in tinned sardines?
Yes. The bones are cooked until they’re soft enough to eat and you’ll barely notice them. They’re also where most of the calcium is - a tin with bones gives you around half the calcium you need in a day.
Do sardines contain a lot of mercury?
No. Sardines are one of the lowest mercury fish you can buy, because they’re small, short-lived and eat plankton rather than other fish. US government testing found sardines had around 10 times less mercury than tinned tuna.
Are sardines good for weight loss?
They can help. A tin contains around 155 calories and 22g of protein, and protein-rich meals tend to keep you fuller for longer. But there’s little evidence that the “sardine fast” (eating only sardines) is a safe way to lose weight.
Are sardines better than fish oil supplements?
For most people, yes. UK dietitians don’t recommend omega-3 supplements for the general population because the evidence of benefit is inconclusive. The evidence for eating oily fish is stronger, and sardines give you protein, calcium, vitamin D and other nutrients that capsules don’t.
Can I eat sardines when I’m pregnant?
Yes. Sardines are a good choice in pregnancy because they’re rich in omega-3s and low in mercury, and have been linked with improving the development of babies’ nervous systems. The NHS advises pregnant women, and those trying for a baby, to have no more than two portions of oily fish a week.
Do sardines contain creatine?
Yes, but not as much as social media suggests. Fish contain roughly 3–10g of creatine per kilogram, so a tin of sardines gives you a few hundred milligrams, not the 5g often claimed.
What’s the difference between sardines and pilchards?
They’re the same fish. Pilchards are simply older, larger sardines, so they offer very similar health benefits.
Are sardines bad for gout or high blood pressure?
They can be in large amounts. Sardines are high in purines, which can trigger gout attacks, and tinned varieties can be salty, which raises blood pressure. If you have either condition, speak to your GP or a dietitian about how much is right for you.