Sardines are one of the most nutrient-dense foods you can eat. A 100-gram serving of cooked sardines delivers nearly 25 grams of protein, close to a gram of omega-3 fatty acids, 382 mg of calcium, and over 300% of your daily vitamin B12 needs. They’re also one of the lowest-mercury fish available, making them safe to eat multiple times per week.
What’s in a Serving of Sardines
The nutritional profile of sardines is remarkably complete. Per 100 grams (roughly one can, drained), cooked sardines provide 24.6 g of protein, 382 mg of calcium, 52.7 micrograms of selenium, 8.9 micrograms of vitamin B12, and 4.8 micrograms of vitamin D. That single serving covers about 38% of your daily calcium, nearly all of your selenium, and a meaningful chunk of your vitamin D, a nutrient most people don’t get enough of from food alone.
The omega-3 content is especially notable: about 473 mg of EPA and 509 mg of DHA per 100 grams. Those are the two forms of omega-3 your body can actually use directly, unlike the type found in flaxseed or walnuts, which your body has to convert (and does so inefficiently). A single can of sardines gives you roughly the same omega-3 dose as a standard fish oil capsule, but bundled with protein, minerals, and vitamins that a supplement can’t replicate.
Heart and Blood Sugar Benefits
EPA and DHA from fish like sardines help lower triglycerides, reduce inflammation in blood vessels, and support healthy blood pressure. These effects are well established across decades of nutrition research, which is why every major dietary guideline recommends eating fish at least twice a week.
Sardines also show promise for blood sugar management. In a pilot trial with newly diagnosed type 2 diabetes patients, those eating a sardine-enriched diet saw their fasting insulin drop by about 35% and their insulin resistance score fall by 39% over six months. A control group eating a standard healthy diet also improved, but the sardine group showed a larger reduction. Both groups also experienced positive shifts in their gut bacteria composition, which plays a role in how the body processes sugar.
Bone Health From Eating the Bones
Because canned sardines are eaten bones and all, they’re one of the richest non-dairy sources of calcium available. The 382 mg per 100-gram serving is more than a glass of milk provides. That calcium comes paired with vitamin D (4.8 micrograms per serving), which your body needs to absorb calcium effectively. This combination makes sardines particularly useful for people who are lactose intolerant, vegan-curious but still eating fish, or simply looking for more ways to protect bone density as they age.
Brain Protection
The omega-3s in sardines are critical building blocks of brain cell membranes, and getting enough of them is linked to slower cognitive decline with age. But sardines offer brain benefits beyond just their fat content. Animal research has found that sardine protein itself acts as a neuroprotective nutrient, reducing oxidative stress in the brain by boosting the activity of key antioxidant enzymes by as much as 62%. In rats fed a high-sugar diet designed to mimic metabolic syndrome, sardine protein reversed the spike in brain glucose levels and reduced markers of cellular damage. While animal studies don’t translate directly to humans, the combination of omega-3s, B12 (essential for nerve function), and selenium (another antioxidant) makes sardines a uniquely brain-supportive food.
Extremely Low Mercury
Mercury is the main reason people worry about eating fish regularly, but sardines are about as safe as it gets. According to FDA testing data, sardines contain an average of just 0.013 parts per million of mercury. For comparison:
- Sardines: 0.013 ppm
- Canned light tuna: 0.126 ppm
- Yellowfin tuna: 0.354 ppm
- Swordfish: 0.995 ppm
Sardines have roughly 75 times less mercury than swordfish. They’re low on the food chain, small, and short-lived, so they don’t accumulate heavy metals the way larger predator fish do. The FDA classifies sardines as a “Best Choice” fish, safe for pregnant and breastfeeding women at two to three servings per week, and safe for young children as one of the preferred low-mercury options.
How Much to Eat Per Week
The Dietary Guidelines for Americans recommend at least 8 ounces of seafood per week for adults on a 2,000-calorie diet. Pregnant and breastfeeding women are advised to eat 8 to 12 ounces weekly from low-mercury sources, and sardines fit squarely in that category. Two to three cans per week is a reasonable target for most people and well within safe limits.
The one group that should moderate their intake is people with gout or elevated uric acid levels. Sardines are a high-purine food, and purines break down into uric acid in the body. Research has found that eating more than two servings of fish per day corresponds to modest increases in uric acid levels, and over a third of gout patients identify seafood as a trigger for flares. If you have gout, you don’t necessarily need to avoid sardines entirely, but keeping intake to a couple of servings per week and tracking your response is a practical approach.
Choosing the Best Can
Canned sardines come packed in water, olive oil, or tomato sauce, and the choice matters more than you might think. Sardines in water are the leanest option and tend to be lower in sodium. Sardines in olive oil have more calories and total fat but also more flavor, and the olive oil adds its own heart-healthy fats. Regardless of packing liquid, the biggest variable to watch is sodium. Some brands load in salt, so look for labels that say “low sodium” or “no salt added” if you’re watching your intake.
Fresh sardines are nutritionally similar to canned but less widely available and more perishable. Canned sardines are cooked during the canning process, so they’re ready to eat straight from the tin. The bones soften during canning, which is why you can eat them whole and get all that calcium.
A Note on Sustainability
Sustainability varies by where your sardines are sourced. The U.S. Pacific sardine fishery is currently closed because the population fell below precautionary levels, with a rebuilding plan targeting recovery by 2035. Most canned sardines sold in the U.S. come from European, Moroccan, or other international fisheries. If sustainability matters to you, check the label for the country of origin and look for certifications from organizations like the Marine Stewardship Council. The fishing methods used for sardines (surface nets targeting dense schools) generally cause minimal habitat damage and low bycatch, which is a point in their favor compared to many other seafood options.