Sardines, Tuna and Mercury: How to Eat Fish Well Without the Worry

Walk past the canned fish aisle of almost any supermarket this year and you will notice something new: the sardine shelf is half empty. Short videos of people cracking open a tin for breakfast, chatter about a “tin a day,” and a wave of posts calling sardines the most underrated food in the store have pushed searches for sardines benefits to levels not seen in years. As of early 2026 the curiosity is still climbing, and it has dragged an older question back with it: how much mercury is in that tin, and how does it compare with the canned tuna already in the pantry?

The honest answer is more reassuring than the internet’s anxiety suggests, and more interesting than its hype. Sardines are small, short-lived and low on the food chain, which is exactly why they collect so little mercury and so much of what nutritionists keep asking people to eat more of.

This explainer separates what large trials and decades of monitoring data actually show from what a 30-second clip can claim. It also gives you a practical way to eat fish well, including tuna, without counting anything on your fingers.

What changed recently: why sardines benefits are suddenly everywhere

Nothing about the fish itself changed. What shifted is attention, and a few pieces of context help explain why it landed now.

The scientific groundwork is older than the trend. In 2018 the American Heart Association published a science advisory confirming its long-standing recommendation of one to two servings of fish per week, with a preference for oily species such as sardines, salmon and herring. That same year a large Cochrane review of omega-3 supplements, covering more than 100,000 participants, found little or no effect of capsules on heart attack or death, a result that pushed many clinicians to say “eat the fish” rather than “take the pill.” The VITAL trial, also reported in 2018, reached a similar neutral verdict for supplements in healthy adults.

Federal fish advice from the FDA and EPA, last revised in 2021 and summarized on MedlinePlus, lists sardines in its “best choices” group, the fish adults can eat two to three times a week and that are specifically encouraged during pregnancy. The 2020 to 2025 Dietary Guidelines for Americans kept their target of at least 8 ounces of seafood per week for adults.

The social media surge added two newer ingredients: budget-conscious eaters rediscovering shelf-stable protein, and a parallel conversation about mercury in fish that had been simmering since tuna sandwiches became a lunchbox worry a generation ago. The result is a rare moment where a viral food fashion and the evidence point in roughly the same direction, with one caveat this article keeps returning to. Enthusiasm is not a serving size, and “more” is not automatically better, mainly because of salt rather than mercury.

What are the sardines benefits, nutrient by nutrient?

Open a standard 3.75-ounce can of sardines packed in oil, drain it, and you are holding about 190 calories of unusually complete food. The protein alone is around 22 grams, comparable to a chicken thigh, and it arrives with every essential amino acid.

The headline nutrient is omega-3 fat. Omega-3s are a family of polyunsaturated fats the body cannot make efficiently and must get from food. The two marine forms, EPA and DHA, total roughly 1 gram per can, which is more than many adults in the United States eat in a week. By comparison, the same weight of canned light tuna in water offers around 0.2 to 0.3 grams.

Then come the quieter contributors. A can supplies about 8 micrograms of vitamin B12, several times the daily requirement, which matters for red blood cells and nerve function. Vitamin D sits near 4 to 5 micrograms, roughly a quarter of the amount most adults are advised to get, in a food category where dietary sources are scarce. Selenium, a mineral used by the body’s antioxidant enzymes, lands around 50 micrograms, close to a full day’s worth.

Because sardines are eaten whole, their soft, edible bones deliver 300 to 350 milligrams of calcium, about a third of the adult target and more than a glass of milk. Choline, iron, phosphorus and niacin round out the list.

What the tin does not contain is also part of the appeal: almost no carbohydrate, very little mercury, and, unlike many processed proteins, no nitrates or fillers. The sodium is the one line on the label worth reading closely, and the next section explains why.

Are canned sardines healthy for you, or does canning spoil the story?

Canning is one of the oldest preservation methods, and for oily fish it is remarkably kind. The fish are cooked in the sealed can, so the omega-3 fats are not exposed to air and oxidize far less than they would in a pan at home. Studies comparing fresh and canned sardines find similar EPA and DHA content, and the long cooking softens the bones enough to eat, which is why canned sardines carry calcium that a fresh grilled fillet does not.

Oil or water? Sardines packed in olive oil absorb a little of that oil and give up a little of their own fat into it, so draining matters more than the label. If you pour the oil away, the omega-3 difference between oil-packed and water-packed is modest. Oil-packed versions taste richer and carry roughly 40 to 60 more calories per can, which is either a bonus or a drawback depending on your goals.

Salt is the real variable. A typical can contains 250 to 350 milligrams of sodium, about 11 to 15 percent of the 2,300-milligram daily upper limit most health agencies use. Versions in tomato or mustard sauce, and some imported brined styles, can double that. Low-sodium or no-salt-added cans exist and taste perfectly good with lemon.

One more canning question people ask: does the lining matter? Modern cans in the United States and Europe have largely moved away from BPA-based linings, and regulatory agencies consider trace exposure from canned food to be below levels of concern. The evidence here is mostly observational and the science is still evolving, so it is fair to say the fish inside the can is a bigger health story than the can itself.

How many sardines a day should you eat?

The question assumes a daily habit, and the evidence does not require one. Guidance from the American Heart Association, the NHS and US dietary guidelines converges on two servings of fish per week, with at least one being an oily fish. A serving for an adult is about 4 ounces cooked, roughly one can of sardines.

Eating a can every day is not dangerous for most healthy adults from a mercury standpoint. Sardines average about 0.013 parts per million of mercury in US monitoring data, around 75 times less than swordfish. You could eat them daily for years and stay far below any exposure threshold. The ceiling is set by other things.

Sodium is the first. Seven cans a week adds roughly 2,000 milligrams of sodium to your week, manageable if the rest of your diet is low in salt, less so if it is not. Purines are the second. Purines are natural compounds in protein-rich foods that the body breaks down into uric acid, and sardines are among the highest-purine foods. For people prone to gout, the Mayo Clinic advises limiting sardines, anchovies and similar fish. Variety is the third. Fish from different waters carry different trace minerals and contaminants, and rotating species spreads both the benefits and the small risks.

A sensible rhythm for most adults looks like three to five cans a week, mixed with other seafood, rather than a rigid daily dose. If you love them daily, choose low-sodium cans, keep other salty foods in check, and talk with your clinician if you have gout, kidney disease or high blood pressure. There is no trial showing that a sardine a day beats a sardine every other day, and there is no need to treat the tin like a prescription.

Mercury in fish: how it gets into the ocean and why size matters

Mercury is a naturally occurring metal, released into the air by volcanoes and, in larger amounts, by coal burning and some industrial processes. It settles into oceans and lakes, where bacteria convert it into methylmercury, the organic form that the body absorbs almost completely from food and clears only slowly.

Methylmercury then climbs. Plankton take up tiny amounts, small fish eat large quantities of plankton, bigger fish eat many small fish, and at each step the mercury concentrates because it is stored in muscle and excreted slowly. Scientists call this biomagnification. A sardine lives one to three years and eats plankton directly. A swordfish may live more than a decade and eat thousands of smaller fish. The difference in their mercury content is not a matter of degree; it is a matter of two orders of magnitude.

In the body, methylmercury binds to proteins and is distributed widely, including across the placenta and into the developing brain, which is why pregnancy advice is stricter. The CDC notes that the half-life in blood is around one to two months, so exposure from an occasional high-mercury meal falls away within a season. Harm from fish-based exposure is seen mainly in populations with very high, sustained intake of large predatory fish, and the classic signs involve the nervous system: tingling, tremor, trouble with coordination, and changes in vision or hearing.

The practical lesson is simple and well supported. Mercury risk from fish tracks the size and lifespan of the species far more than how often you eat fish overall. Small fish, eaten often, are the low-mercury way to collect the benefits that large trials have linked to seafood.

Canned tuna vs sardines: a side-by-side on mercury and omega-3

Canned tuna is not one food. The light tuna most people buy is mostly skipjack, a fast-growing species that stays small. White tuna is albacore, a larger fish that lives longer and carries roughly three times the mercury. Tuna steaks and sushi-grade tuna are often yellowfin or bigeye, and bigeye sits in the group federal advice says to avoid during pregnancy.

Fish (per 100 g, drained)	Average mercury (ppm)	EPA + DHA (g)	Calcium (mg)	US advice category
Sardines, canned	0.013	about 1.0	380	Best choice: 2–3 servings/week
Canned light tuna (skipjack)	0.126	0.2–0.3	about 10	Best choice: 2–3 servings/week
Canned white tuna (albacore)	0.350	0.7–0.9	about 15	Good choice: 1 serving/week
Yellowfin tuna	0.354	0.2–0.3	about 10	Good choice: 1 serving/week
Bigeye tuna	0.689	0.3–0.5	about 10	Avoid in pregnancy
Swordfish (for scale)	0.995	0.7–0.8	about 5	Avoid in pregnancy

Mercury figures come from long-running FDA monitoring averages; nutrient values are typical USDA composition data and vary by brand and packing liquid.

Two things stand out. First, canned light tuna is a legitimately low-mercury food and remains in the best-choices group, so the lunchbox fear was always overstated for the standard can. Second, sardines give you three to five times the omega-3 of light tuna for one tenth the mercury, plus calcium that tuna simply does not have because the bones are removed.

The NHS frames the same reality differently: it advises no more than four medium cans of tuna a week for people who are pregnant or trying to conceive, and treats canned tuna as a non-oily fish because canning removes much of its oil. Sardines count as oily. If your pantry holds both, the evidence favors reaching for the tuna a couple of times a week and the sardines more often.

What the evidence actually says about eating oily fish

It helps to sort the claims by the kind of evidence behind them, because they are not all equal.

Strongest: eating fish regularly is associated with lower rates of fatal coronary heart disease. This comes from large prospective cohort studies following hundreds of thousands of people for decades, pooled in meta-analyses that the American Heart Association reviewed in its 2018 advisory. The association is consistent across countries, roughly a 15 to 20 percent lower risk for one to two servings per week compared with little or none. Observational data cannot prove cause, but the consistency, the plausible mechanisms (lower triglycerides, improved heart rhythm stability, lower blood pressure) and the lack of any signal of harm make this the best-supported benefit.

Moderate: omega-3 intake lowers blood triglycerides. This is confirmed by randomized trials, mainly of concentrated supplements, with effects of 15 to 30 percent at higher intakes. Whole-fish intakes produce smaller but measurable changes.

Mixed: omega-3 supplements for preventing heart attacks and strokes in the general population. The 2018 Cochrane review and the VITAL and STRENGTH trials were largely neutral. One prescription-strength purified EPA product did reduce cardiovascular events in a 2018 trial of high-risk patients already on statins, but that is a medicine decision for a cardiologist, not a reason to buy capsules.

Weak to preliminary: effects on mood, cognition, inflammation markers, eye health and joint pain. Some small randomized trials show benefit, others do not, and much of the evidence is observational.

Not supported: claims that sardines reverse disease, melt fat or detoxify anything. The honest summary is that sardines are a reliable way to get nutrients that strong observational evidence links to heart health, and a reasonable but unproven bet on several other outcomes.

Why do I feel good after eating sardines?

Readers describe it the same way: a tin at lunch, then a steadier afternoon than a sandwich usually gives. Several ordinary mechanisms can explain the feeling without reaching for mysticism.

Protein is the first. Twenty-two grams of complete protein slows stomach emptying and raises satiety hormones such as peptide YY, so blood sugar climbs gently and the mid-afternoon crash that follows a refined-carbohydrate meal is less likely. That alone can feel like better mood and focus.

Fat is the second. Oily fish is digested slowly and provides sustained energy, and a meal with fat and protein but little starch produces a flatter glucose curve than most desk lunches. Randomized feeding studies consistently show this pattern, even if they rarely measure “feeling good” directly.

Vitamin B12 is a plausible third contributor for anyone whose intake has been marginal, since low B12 is linked to fatigue and low mood. A single can covers several days’ needs, though the effect would build over weeks rather than hours.

Then there is omega-3 and the brain. DHA is a structural component of brain cell membranes, and observational studies link higher fish intake with lower rates of depression. Meta-analyses of randomized trials using EPA-rich supplements show a small average benefit for people with diagnosed depression, mostly as an add-on to standard treatment, and little effect in people without depression. For a healthy adult, the evidence does not support an immediate omega-3 mood lift from one meal.

So the feeling is probably real, and probably comes from eating a satisfying, blood-sugar-friendly meal rather than from any single magic compound. If persistent low mood is part of why you noticed, that is a conversation for a clinician, not a can.

Do sardines burn belly fat?

No food burns fat. The body loses fat when it spends more energy than it takes in over weeks and months, and the arrangement of that fat around the waist is shaped mostly by genetics, age, hormones and overall weight change. A sardine cannot target a location any more than a walk can.

What sardines can do is make a calorie deficit easier to live with. Protein is the most satiating macronutrient per calorie, and trials of higher-protein diets show modest advantages for preserving muscle during weight loss and for reducing hunger. A can of sardines packs that protein into fewer than 200 calories, which compares favorably with most ready-to-eat foods.

The specific claim that omega-3s reduce abdominal fat comes from a handful of small trials, several in people with metabolic syndrome, where fish-oil supplementation produced small decreases in waist circumference or liver fat. Larger and longer studies have been inconsistent, and a systematic review of omega-3 supplements and body weight found no meaningful effect on their own. The evidence is best described as preliminary and, where positive, small.

There is a stronger indirect story. Observational research links Mediterranean-style eating, with fish two or more times a week, to less weight gain over time and lower rates of type 2 diabetes. Sardines are a convenient way to follow that pattern.

If weight is a goal, the useful framing is this: swap a processed lunch for sardines on whole-grain toast with tomatoes and you will likely feel fuller for fewer calories. That is a real and repeatable benefit. Expecting a tin to reshape your midsection is not, and anyone promising it is selling a story rather than describing evidence.

Bones, calcium and vitamin D: the benefit most people throw away

Many first-time sardine eaters pick out the spine. It is understandable, and it discards the single most unusual nutrient the fish offers.

Canned sardine bones are cooked until they crumble between the teeth, and they are almost pure calcium phosphate, the same mineral complex that makes up human bone. A drained can delivers roughly 300 to 350 milligrams of calcium, about a third of the 1,000 milligrams most adults need and more than a cup of milk. For people who do not drink milk, whether by preference, lactose intolerance or diet, this is one of the few whole foods that closes the gap without fortification.

Calcium absorption depends on vitamin D, and sardines bring their own. The 4 to 5 micrograms in a can is around a quarter to a third of the daily recommendation, and vitamin D is otherwise hard to find in food; oily fish, egg yolks and fortified products are the short list. Pairing the two in one food is nutritionally elegant, and it is why sardines appear in NHS and NIH guidance on both nutrients.

Phosphorus and magnesium, also present, complete the bone-mineral set. The evidence that food-based calcium supports bone density is observational but consistent, and food sources avoid the questions that have been raised about high-dose calcium supplements and cardiovascular events, questions that remain unsettled in randomized data.

Two practical notes. People with chronic kidney disease are often asked to limit phosphorus, and should check with their care team before making sardines a habit. And if the texture of bones is the barrier, mashing sardines with lemon, mustard and a little olive oil makes them disappear while keeping every milligram.

Who should be cautious: pregnancy, children, gout, kidney disease and salt

For most adults the risk side of the ledger is short. For a few groups it deserves a closer look, and the advice differs by group rather than being a single warning.

Pregnancy and breastfeeding. Here the evidence actually favors more fish, not less, as long as it is low in mercury. Federal advice, summarized on MedlinePlus, recommends 8 to 12 ounces per week from the best-choices list, which includes sardines and canned light tuna, because DHA supports fetal brain development. Albacore is limited to one serving a week; bigeye tuna, swordfish, shark, king mackerel, marlin, orange roughy and tilefish from the Gulf of Mexico are to be avoided. The NHS adds that pregnant people should keep oily fish to two portions a week and canned tuna to four cans.

Children. The same low-mercury list applies, with smaller portions: about 1 ounce at ages 1 to 3, rising to 4 ounces by age 11. Sardines are an easy fit because they are soft and bone-safe.

Gout. Sardines, anchovies, herring and mussels are high in purines, and the Mayo Clinic lists them among foods to limit during flares and for people with recurrent attacks. Someone with well-controlled gout may tolerate occasional servings; that is a decision for their clinician.

Kidney disease. Protein, phosphorus and sodium are often restricted, and a can of sardines is rich in all three. Ask your renal dietitian before adding them regularly.

High blood pressure or heart failure. Sodium is the issue, not the fish. Choose no-salt-added cans and count the tin against your daily limit.

Fish allergy. Sardines are a finned fish and can trigger the same reactions as any other; a prior fish allergy is a reason to avoid them entirely.

Common myths about sardines, canned tuna and mercury

Viral claims tend to be half true, which is what makes them stick. Here are the ones circulating most, held up against the evidence.

“Sardines detox heavy metals.” There is no mechanism by which a food pulls mercury or lead out of the body. The grain of truth is that sardines are rich in selenium, and laboratory and animal studies show selenium binds methylmercury and may blunt its toxicity. Human evidence is observational and far from settled. Sardines are a low-mercury choice, not a treatment for anything.

“All canned tuna is dangerous.” Canned light tuna sits in the best-choices group and is specifically recommended during pregnancy. The caution applies to albacore in larger amounts and to bigeye and other big predatory fish.

“Fish oil capsules do everything fish does.” Large randomized trials of supplements in healthy adults have been mostly neutral, while observational data on whole fish remain positive. Fish brings protein, vitamin D, selenium and calcium that a capsule does not, and it usually replaces a less healthy food on the plate.

“Eating sardines daily is risky because of mercury.” At 0.013 ppm, a daily can for decades stays far below any exposure limit. Daily sardines raise sodium and purine questions, not mercury ones.

“Sardines melt fat and fix hormones.” No food does either. The protein helps satiety, which can support weight management within an overall calorie balance.

“Fresh is always better than canned.” For sardines the omega-3 content is similar, and only the canned version offers edible bones and their calcium.

“Mercury stays in you forever.” The CDC puts the half-life of methylmercury in blood at about one to two months. Exposure from a single high-mercury meal largely clears within a season.

How to eat fish well without the worry: a practical week

Guidelines read like arithmetic, so here is what they look like on real plates. The aim is two or more seafood servings a week, one of them oily, chosen from low-mercury species, with tuna in rotation rather than in the lead.

A week that meets every major recommendation might look like this. Sardines twice, perhaps mashed on rye with pickled onion one day and tossed through hot pasta with garlic, chili and breadcrumbs another. Canned light tuna once, in a salad with white beans and parsley rather than mayonnaise, which keeps the sodium and saturated fat down. Salmon, trout, mackerel or herring once if budget allows; frozen fillets are nutritionally equivalent to fresh and often fresher than the fish counter. That is four servings, roughly 14 to 16 ounces, with total mercury intake well below the level at which US and WHO advisories begin to apply.

Albacore, yellowfin or a tuna steak can slot in once in a given week in place of the light tuna, following the one-serving guidance. Swordfish, shark and king mackerel are occasional foods for adults who are not pregnant and off the list entirely for those who are.

A few habits make the rest easy. Drain and rinse canned fish to shave sodium. Read the label for “skipjack” or “light” if mercury is your concern and “no salt added” if blood pressure is. Keep opened cans refrigerated and eat them within two days; both tuna and sardines can develop histamine if left warm, causing a flushing, headache-and-rash reaction called scombroid poisoning that looks like an allergy but is a storage problem.

Variety is the quiet safeguard here. Rotating species spreads out any single contaminant, broadens the nutrients you collect, and, not incidentally, stops the tin from becoming a chore.

When to see a doctor about fish, mercury or a new sardine habit

Most people will never need this section. A few situations do warrant a conversation with a clinician, and some need prompt care.

Seek medical attention promptly for possible fish allergy or scombroid poisoning: hives, swelling of the lips or face, wheezing, flushing, a pounding headache, racing heart or vomiting within minutes to a couple of hours of eating fish. Trouble breathing or throat tightness is an emergency; call emergency services.

Ask for an evaluation if you notice persistent symptoms that can signal mercury exposure, especially if you eat large predatory fish several times a week: numbness or tingling around the mouth, fingers or toes; tremor; unsteadiness or clumsiness; blurred or narrowed vision; hearing changes; or difficulty with memory and concentration. A simple blood mercury test can clarify things, and these symptoms have many other causes that also deserve attention.

Talk with your clinician or a registered dietitian before making sardines a daily food if you have gout, chronic kidney disease, heart failure or high blood pressure that is hard to control, since purines, phosphorus and sodium may need limiting. The same applies if you take a blood thinner and plan a large increase in oily fish or are considering fish oil supplements; omega-3s have a mild effect on clotting, and your prescriber should know.

If you are pregnant, planning pregnancy or breastfeeding, your obstetric team can confirm which fish fit your situation; the general advice is to eat more low-mercury fish, not less.

Finally, if the reason you noticed sardines was fatigue, low mood or unexplained weight change, treat the food as a bonus, not a diagnosis. Those symptoms merit a proper assessment, and no change in diet should replace, delay or alter a prescribed medicine without the prescribing clinician’s agreement.

Frequently asked questions

Are canned sardines healthy for you?

Yes, canned sardines are among the most nutrient-dense foods in the supermarket. Canning preserves their omega-3 fats, softens the bones so you gain calcium, and leaves protein, vitamin D, B12 and selenium intact. Mercury is very low because sardines are small and short-lived. The one label line worth watching is sodium, which ranges from about 250 milligrams in plain cans to double that in sauced varieties; low-sodium versions are widely available.

How many sardines a day should you eat?

There is no evidence you need sardines every day. Guidelines recommend two fish servings a week, one of them oily, and a 4-ounce serving is roughly one can. Eating a can daily is safe for most healthy adults from a mercury standpoint, but it adds about 2,000 milligrams of sodium a week and a high purine load. Three to five cans weekly, rotated with other seafood, suits most people; anyone with gout, kidney disease or hypertension should check with a clinician first.

How much mercury is in canned tuna compared with sardines?

Canned light tuna averages about 0.126 parts per million of mercury and albacore about 0.35, while sardines average around 0.013. All three are permitted in US advice, but light tuna and sardines sit in the best-choices group for two to three weekly servings, whereas albacore is limited to one. Bigeye tuna, at roughly 0.69, is on the avoid list for pregnancy. The NHS separately advises no more than four cans of tuna a week while pregnant.

Why do I feel good after eating sardines?

The most likely explanation is the meal itself: about 22 grams of protein plus fat and almost no starch produces a gentle blood sugar curve and strong satiety, so the afternoon slump is less likely. A boost in vitamin B12 may help over weeks if intake was low. Omega-3s are linked to mood in observational studies, but randomized trials show only small effects, mainly as add-on therapy in diagnosed depression, not an immediate lift from one meal.

Do sardines burn belly fat?

No food burns fat, and nothing targets the abdomen specifically. Sardines can help with weight management indirectly because their protein is highly satiating for fewer than 200 calories a can, making a calorie deficit easier to sustain. Small trials of omega-3 supplements have shown minor changes in waist size in people with metabolic syndrome, but systematic reviews find no meaningful effect on body weight overall. Treat the claim as preliminary at best.

Is it safe to eat sardines every day during pregnancy?

Sardines are on the best-choices list in US federal advice, which recommends 8 to 12 ounces of low-mercury fish per week during pregnancy, so two to three cans weekly fits comfortably. The NHS advises limiting oily fish to two portions a week in pregnancy because of other trace pollutants, which is a reasonable upper bound. Daily intake is not recommended by either body; your obstetric team can tailor this to you.

Is canned tuna an oily fish like sardines?

Fresh tuna is an oily fish, but canned tuna is not counted as one by the NHS because the canning process removes much of its oil. Canned light tuna provides roughly 0.2 to 0.3 grams of EPA and DHA per 100 grams, compared with about 1 gram in sardines. It remains a lean, low-mercury protein and a good weekly choice, but it does not satisfy the “one oily fish serving a week” recommendation on its own.

Can eating too much fish cause mercury poisoning?

It is possible but uncommon, and almost always involves frequent meals of large predatory fish such as swordfish, shark, king mackerel or bigeye tuna over months. Symptoms involve the nervous system: tingling, tremor, poor coordination, and vision or hearing changes. The CDC notes methylmercury clears from blood with a half-life of one to two months. Low-mercury fish such as sardines and canned light tuna can be eaten several times a week without approaching exposure limits.

Should I eat the bones in canned sardines?

Yes, if you can. The bones are cooked soft during canning and supply 300 to 350 milligrams of calcium per can along with phosphorus, roughly a third of an adult’s daily calcium need. Removing them discards the nutrient that most distinguishes sardines from other fish. People with chronic kidney disease who are limiting phosphorus should ask their care team first. Mashing sardines with lemon and mustard hides the texture completely.

Are fish oil capsules as good as eating sardines?

The evidence says no for most healthy adults. Large randomized trials and a 2018 Cochrane review found omega-3 supplements had little or no effect on heart attacks or deaths, while observational studies consistently link whole fish intake with lower cardiovascular risk. Sardines also deliver protein, vitamin D, calcium and selenium that capsules lack. A prescription-strength omega-3 medicine helped some high-risk patients in one trial, but that is a decision for your prescribing clinician.

References

• Fish and shellfish: nutrition and safety (NHS)
• Mercury (MedlinePlus)

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.