One can of sardines packed in oil, bones included, has 351 mg of calcium, 4.4 µg of vitamin D, 8.2 µg of vitamin B12 and 0.9 g of EPA plus DHA, the long omega-3 fats of fish. The vitamin B12 is more than three times the daily value. The numbers on this page are for the drained fish with its soft bones, 92 g to a can, which comes to 191 calories.
Sardine is a loose name more than one species. The terms sardine and pilchard are not precise, and the Codex standard for canned sardines allows 21 species. The true sardine is the European pilchard, Sardina pilchardus, but some cans sold as sardines hold sprats or round herring instead.
Only two small trials have fed people sardines, both in people with type 2 diabetes or prediabetes, and their results were mixed. Most of the research below is about fish in general or about omega-3 capsules, and each card says so. Sardines feed almost exclusively on zooplankton and sit low in the food chain, and the FDA lists them as a Best Choice for low mercury.
Health benefits of sardines
None of the studies below reaches strong evidence. Only two trials fed people sardines, in 152 and 35 people, and the two big omega-3 capsule trials here found no drop in major heart events. Large cohorts link fish to lower heart risk only in people who already have vascular disease. Here is what 20 studies found, strongest evidence first, from sardine trials and fish oil capsules to calcium from bones, gout and fish allergy, including the results that found nothing.
Children who ate about 300 g of oily fish a week for 12 weeks had slightly lower triglycerides and higher HDL cholesterol
Randomized trial in 199 Danish children aged 8 to 9. They ate about 300 g a week of oily fish or of poultry as the control. Triglycerides fell 0.05 mmol/L and HDL rose 0.07 mmol/L, while blood pressure, heart rate variability and blood sugar handling did not change. The triglyceride drop was seen in boys only. The fish was oily fish in general, not sardines, and the children were healthy.
Omega-3 fats, mostly from capsules, did not lower deaths from any cause but cut triglycerides by about 15%
Cochrane review of 86 randomized trials (162,796 people) lasting 12 to 88 months. Most trials used capsules, and the authors found little evidence about eating fish, so this does not show what sardines do. Death from any cause was unchanged (risk ratio 0.97, range 0.93 to 1.01), and coronary heart disease events were slightly lower (0.91), with low certainty.
A 1 g omega-3 capsule a day for 7.4 years did not reduce serious vascular events in 15,480 people with diabetes
Randomized, placebo-controlled trial in people with diabetes and no known heart disease. A serious vascular event happened in 8.9% on omega-3 and 9.2% on olive oil capsules (rate ratio 0.97, range 0.87 to 1.08). These were capsules, not fish. The British Heart Foundation and others funded the trial.
A 1 g marine omega-3 capsule a day for a median of 5.3 years did not lower major cardiovascular events or cancer in 25,871 adults
Randomized, placebo-controlled trial in US men aged 50 or older and women aged 55 or older. Major cardiovascular events happened in 386 people on omega-3 and 419 on placebo (hazard ratio 0.92, range 0.80 to 1.06). Heart attacks were lower (0.72), but that was a secondary result. These were capsules, not fish. The National Institutes of Health and others funded the trial.
Show 16 more studies
Adding 200 g of sardines a week for a year lowered insulin resistance and raised HDL cholesterol in older adults with prediabetes
Randomized trial in 152 adults aged 65 or older in Barcelona, with fasting glucose of 100 to 124 mg/dL. Both groups got the same diabetes-prevention diet; one added 200 g of sardines a week. Insulin resistance (HOMA-IR) was lower, and triglycerides and blood pressure fell. Eighteen people in the control group and 12 in the sardine group dropped out. The results are risk scores and blood markers, from a single trial.
Eating 100 g of sardines 5 days a week for 6 months did not improve blood sugar control in 35 people with type 2 diabetes
Pilot randomized trial in people not yet on diabetes drugs. Insulin resistance fell in both groups (HOMA-IR by 39.2% with sardines and 21.8% without). Only the sardine group raised adiponectin, by 40.7%, and their omega-3 index rose 2.6 points against 0.6. A small pilot, so the results are early.
Calcium from small fish eaten with their bones was absorbed about as well as calcium from milk
Absorption test in 19 healthy adults aged 21 to 28. Each meal had about 397 mg of calcium from small Bengali fish or 377 mg from skimmed milk. Absorption was 23.8% from the fish and 21.8% from the milk, not a significant difference. These were small whole fish, not canned sardines.
Eating 170 g of oily fish a day for 6 weeks modestly improved plaque psoriasis
Crossover trial in 18 patients, who ate 170 g of white fish a day for 4 weeks and were then switched between white and oily fish for 6 weeks each. Psoriasis improved by 11% and 15% on oily fish, with a rise in blood EPA, and did not improve on white fish. The authors list sardine among the fish they recommend. It was a very small trial.
A drink with a peptide made from sardine protein lowered systolic blood pressure by 9.3 mm Hg after 4 weeks
Double-blind, placebo-controlled trial in 29 people with high-normal blood pressure or mild hypertension. They drank 100 ml with 3 mg of valyl-tyrosine, a short peptide from sardine muscle, twice a day. Diastolic pressure fell 5.2 mm Hg, and pressure crept back up during the 4-week recovery period. This was a peptide drink, not whole sardines.
Eating more fatty fish was linked to a lower risk of coronary heart disease, but eating lean fish was not
Meta-analysis of 19 prospective studies comparing the highest with the lowest fish intake. Fatty fish went with lower coronary heart disease incidence (risk ratio 0.92), coronary heart disease death (0.83) and total mortality (0.97). Sardines are a fatty fish, but the review does not report them alone. A link, not proof.
Eating at least 175 g of fish a week was linked to fewer heart events and deaths in people with vascular disease, but not in the general population
Pooled analysis of 4 cohorts with 191,558 people from 58 countries. In people with vascular disease, 175 g a week (about 2 servings) went with a hazard ratio of 0.84 for major cardiovascular disease and 0.82 for death. In the general population, 350 g or more was not linked to either (0.95 and 0.96). Omega-3-rich fish were linked to lower risk (0.94 per 5 g).
Each extra 20 g of fish a day was linked to a 4% lower risk of cardiovascular death but only marginally lower risk of death from any cause
Meta-analysis of 14 prospective cohorts (911,348 people, 75,451 deaths). Risk ratios were 0.96 for cardiovascular death and 0.98 for all-cause death. The link held only in Asian studies; in Western studies the lowest risk sat near 20 g a day. The authors suggest looking at fish types and cooking methods.
Eating more fish was linked to slightly higher type 2 diabetes risk in women and no link in men
Pooled analysis of 28 cohorts (956,122 people, 48,084 diabetes cases). In women, each extra 100 g a week of fatty fish went with a rate ratio of 1.04 (range 1.01 to 1.07), and total fish with 1.02. All links were null in men. Results varied by region. The authors say cooking methods, accompanying foods or pollutants may play a role.
People who ate the most fish had a lower risk of dementia (risk ratio 0.82) than those who ate the least
Meta-analysis of 35 observational studies. The highest fish intake was also linked to less cognitive impairment (0.82) and less Alzheimer’s disease (0.80), and 150 g a day went with a 30% lower risk of cognitive impairment. This cannot show that fish itself protects. One author works for Bolton Food, a food company.
Men who ate the most seafood had 1.51 times the risk of gout of men who ate the least
Study of 47,150 US men followed for 12 years, with 730 new gout cases. Comparing the highest with the lowest fifth, the risk was 1.41 for meat and 1.51 for seafood, and 0.56 for dairy. The study did not look at sardines on their own.
Toenail mercury from regular fish eating was not linked to cardiovascular disease in Spanish adults at high risk
Case-control study inside the PREDIMED trial with 147 cases and 267 matched controls. Mean toenail mercury was 0.63 µg/g in cases and 0.67 in controls. None of mercury, fish intake and omega-3 intake was linked to disease (highest versus lowest mercury quarter: 0.71, range 0.34 to 1.14). The numbers are small, so a small effect cannot be ruled out.
Canned sardine proteins bound allergy antibodies from 51% of fish-allergic patients in lab tests
Lab study using blood serum from 53 people with fish allergy against 17 canned fish products, two of them sardine. Canning cut the main allergen, parvalbumin, but other heat-stable allergens still bound antibodies. The authors say canned fish may not be safe for all people with fish allergy.
Calcium from whole small fish with bones was available to rats, though perhaps less than from milk
Balance study in 4 groups of 6 young rats fed small whole Bangladeshi fish or skimmed milk for 28 days. The authors suggest small fish with bones may be an important calcium source in human diets.
A peptide mix made from sardine protein improved glucose tolerance in hypertensive rats
Stroke-prone hypertensive rats drank water with sardine peptide (1 g/kg a day), captopril or plain water for 4 weeks. Fasting glucose and insulin did not differ, but blood sugar rose less after a glucose load with the peptide. This was a protein hydrolysate in rats, not whole fish.
Sardine peptides with quercetin lowered blood pressure in hypertensive rats
Lab and rat study of a mix of sardine peptides and the plant compound quercetin. In rats the mix lowered systolic pressure, serum angiotensin II and heart weight. This was a processed peptide mix, not a sardine meal.
Who should be careful with sardines
Most people can eat sardines freely. Take a little care if one of these applies:
- Gout. Raw sardines hold about 210 mg of purines per 100 g, in the large-amount group of one Japanese food analysis. In a US study of 47,150 men, the highest seafood intake went with 1.51 times the risk of gout, but sardines were not studied alone. If you have gout or high uric acid, ask your clinician how much to eat.
- Limiting sodium. One can has 282 mg of sodium, 12% of the Daily Value. If you watch salt, check the label and look for no-salt-added cans.
- Fish allergy. Fish is one of the major food allergens in the US, and canning does not make sardines safe for everyone: in a lab test, canned sardine proteins bound allergy antibodies from 51% of 53 people with fish allergy. Ask your allergist before trying canned fish.
How to choose, store and eat sardines
- Canned in oil, with bones: the form behind this page’s numbers, with 351 mg of calcium per can. In a 19-person test, calcium from small soft-boned fish was absorbed about as well as from milk (23.8% against 21.8%).
- Oil, brine or tomato sauce: in a Porto study of opened cans kept at 4 °C, sardines in brine or oil kept their full quality for about 1 day, and sardines in tomato sauce for up to 3 days.
- Fresh, marinated or home-preserved: cook fresh sardines through. Raw or lightly processed sardines can carry the parasite Anisakis, though none turned up in 750 sardines from one Italian fishing ground, and in 2023 a botulism outbreak in Bordeaux, France, sickened 15 people and was linked to locally produced canned sardines at a restaurant.
Keep unopened cans in a cool, dry cupboard, since canned fish typically lasts one to five years, and keep opened sardines in the fridge. Sardines are low in mercury: the FDA found an average of 0.013 ppm in 90 samples, lists them as a Best Choice, and advises 2 to 3 servings a week of Best Choices in pregnancy.
Sources
- Fish, sardine, Atlantic, canned in oil, drained solids with bone (FDC ID 175139). USDA FoodData Central, SR Legacy.
- Kaneko K, Aoyagi Y, Fukuuchi T, Inazawa K, Yamaoka N. Total purine and purine base content of common foodstuffs for facilitating nutritional therapy for gout and hyperuricemia. Biol Pharm Bull. 2014.
- Choi HK, Atkinson K, Karlson EW, Willett W, Curhan G. Purine-rich foods, dairy and protein intake, and the risk of gout in men. N Engl J Med. 2004.
- Taki AC, Ruethers T, Nugraha R, et al. Thermostable allergens in canned fish: evaluating risks for fish allergy. Allergy. 2023.
- Food allergies. US Food and Drug Administration.
- Hansen M, Thilsted SH, Sandström B, et al. Calcium absorption from small soft-boned fish. J Trace Elem Med Biol. 1998.
- Cruz R, Pereira V, Pinho T, Ferreira IMPLVO, Novais C, Casal S. Safety and quality of canned sardines after opening: a shelf-stability study. Foods. 2022.
- Serracca L, Battistini R, Rossini I, et al. Food safety considerations in relation to Anisakis pegreffii in anchovies and sardines fished off the Ligurian Coast. Int J Food Microbiol. 2014.
- Courtot-Melciolle L, Jauvain M, Siefridt M, et al. Food-borne botulism outbreak during the Rugby World Cup linked to marinated sardines in Bordeaux, France, September 2023. Euro Surveill. 2023.
- Canned fish. Wikipedia.
- Advice about eating fish. FDA and EPA. Revised 2021.
- Mercury levels in commercial fish and shellfish (1990-2012). US Food and Drug Administration.
History of sardines
The word sardine reached English in the early 15th century, from French, Latin and Greek, and may point to the island of Sardinia, around which the fish were once said to be abundant. A later Greek writer, Athenaeus, quotes a passage from Aristotle that names the fish sardinos.
Sardine and pilchard are not precise names. The UK’s Sea Fish Industry Authority classes sardines as young pilchards, and one rule of thumb calls fish shorter than 15 cm sardines and larger ones pilchards. Wikipedia lists the European pilchard, Sardina pilchardus, as the true sardine.
Pilchard fishing and processing thrived in Cornwall from about 1750 to about 1880. The catch was 47,000 hogsheads in 1871 and only 9,477 in 1877, and a hogshead held 2,300 to 4,000 fish. Most were pressed and exported to Roman Catholic countries such as Italy and Spain. The name Cornish Sardines was later entered in the EU register of protected geographical indications under a 2009 regulation.
Canning grew out of a prize. In 1810 the French government paid Nicolas Appert 12,000 francs for a way to preserve food in sealed glass containers, on condition that he make his method public, and the same year Peter Durand patented a tin can. Sardines suited the tin because they could be packed tightly and carried without a fridge. The saying packed like sardines appears in French in 1829 as encaissés comme des sardines.
The US canning industry peaked in the 1950s. The canneries of Cannery Row in Monterey, California, the setting of John Steinbeck’s novel, failed in the mid-1950s. The last large US sardine cannery, the Stinson Seafood plant in Prospect Harbor, Maine, closed on 15 April 2010 after 135 years. In April 2015 a West Coast fisheries council moved to halt the Pacific sardine season after a collapse in stocks.
In Marseille, the local habit of exaggerating is linked to a folk tale about a sardine that blocked the port in the 18th century. In fact it was a ship named the Sartine.
Sources
- Sardine. Wikipedia.
- Canned fish. Wikipedia.
- Nicolas Appert. Wikipedia.
- Parrish RH, Serra R, Grant WS. The monotypic sardines, Sardina and Sardinops: their taxonomy, distribution, stock structure, and zoogeography. Can J Fish Aquat Sci. 1989.
- Commission Implementing Regulation (EU) 2017/910 approving amendments to the specification for Cornish Sardines (PGI). It notes the name was registered under Regulation (EC) No 1182/2009.
Frequently asked questions about sardines
Are sardines good for you?
For most people, yes. One can of sardines packed in oil, bones included, has 191 calories, 22.7 g of protein, 351 mg of calcium, 8.2 µg of vitamin B12 and 0.9 g of EPA plus DHA. The research on health effects is thin: only two small trials have fed people sardines, and the two big omega-3 capsule trials here found no drop in major heart events. In a pooled cohort analysis, fish went with fewer heart events and deaths in people with vascular disease but not in the general population.
Can you eat the bones in canned sardines?
Yes, and the bones hold much of the calcium. The 351 mg of calcium per can on this page is for sardines drained with their bones. In a 19-person test, calcium from small soft-boned fish was absorbed about as well as from milk, 23.8% against 21.8%, but those were small Bengali fish and not canned sardines. No trial here tested calcium absorption from canned sardines.
Are sardines high in mercury?
No, sardines are among the lowest-mercury fish. FDA testing found an average of 0.013 ppm in 90 samples, and the FDA and EPA list sardines as a Best Choice. In Spanish adults at high heart risk, toenail mercury from regular fish eating was not linked to cardiovascular disease.
How many cans of sardines can you eat a week?
No study here sets an ideal amount. The sardine trials used 200 g a week for a year, which is about two cans, and 100 g five days a week for 6 months. The Dietary Guidelines for Americans advise at least 8 ounces of seafood a week (about 227 g), and one can is 92 g, so you can mix sardines with other fish. Each can also adds 282 mg of sodium.
Are canned sardines high in sodium?
They have a moderate amount. One can has 282 mg of sodium, 12% of the Daily Value, and 100 g has 307 mg. If you limit salt, check the label and look for no-salt-added cans.
Are sardines good for gout?
They are a food to be careful with. Raw sardines hold about 210 mg of purines per 100 g, in the large-amount group of one Japanese analysis. Among 633 people with gout, those with the highest purine intake over 2 days had 4.76 times the odds of an attack compared with the lowest. Neither study tested sardines alone, so ask your clinician how much is safe for you.
Are sardines safe during pregnancy?
Yes, in the amounts the FDA and EPA advise. Sardines are on the Best Choices list, and the advice in pregnancy and breastfeeding is 2 to 3 servings a week of Best Choices, with a serving of 4 ounces. One can (92 g) is a little under that. The FDA also says moderate evidence shows fish in pregnancy can help a baby’s brain development.
Do sardines help with blood sugar or diabetes?
The evidence is mixed. In 152 older adults with prediabetes, 200 g of sardines a week for a year lowered insulin resistance. In 35 people with type 2 diabetes, 100 g five days a week for 6 months did not improve blood sugar control. Large cohorts found no link between fish and diabetes in men and a slightly higher risk in women, so check portions and choices with your care team.