Are canned sardines a healthy choice?

Yes. Harvard Health Publishing says sardines are an excellent source of protein and heart-healthy omega-3 fats, and canned sardines are widely available and less expensive than fresh.

Sardines are small fish, and that size works in their favor. Harvard Health says anchovies, herring, mackerel and sardines are excellent sources of protein, heart-healthy omega-3 fats and micronutrients such as iron, zinc and vitamin B12. Using seafood in place of beef, pork or chicken means less saturated fat and more omega-3s, which may help explain why people who eat fish a couple of times a week are less likely to have heart attacks or die from heart disease than people who avoid fish.

The tiny bones are the bonus. Because you often eat the whole sardine, bones included, Harvard Health says small fish are also rich in calcium and vitamin D. Its bone-health article lists sardines among proteins that are also calcium-rich, a two-for-one benefit. The Tufts Health & Nutrition Letter adds that canned sardines, salmon and mackerel can outdo fresh or frozen fish in calcium because they are canned with the bones, and the heat of canning makes those bones soft enough to eat. That advantage does not apply to canned tuna.

Smaller fish also carry fewer contaminant worries. Harvard Health says small fish are less likely to contain mercury and PCBs than large species like tuna and swordfish, which feed on smaller fish and concentrate the toxins. Sardines also feature prominently in the traditional Mediterranean diet.

Two shopping notes. Tufts says omega-3s survive canning, but fish packed in oil can lose some of those fats into the oil when drained, so water-packed is a good pick. And Harvard Health notes that most canned anchovies are high in sodium, which can raise blood pressure, so check the label if you are watching yours.

How much fish is enough? Harvard Health says both the Dietary Guidelines for Americans and the American Heart Association recommend that adults eat at least two servings of seafood each week. Farmed salmon and canned tuna are good swaps for hamburgers and cold cuts, but Harvard Health says working smaller fish into your meals is even better. The micronutrients matter too: Harvard Health notes that zinc contributes to a healthy immune system, and vitamin B12 helps form the red blood cells that carry oxygen and keeps nerves healthy.

The calcium in those soft bones does real work. Harvard Health's bone article says calcium is one of the main ingredients of bone, and the body does not make it on its own, so it has to come from food (the safest and most effective source) or supplements. When there is not enough calcium in the bloodstream, the body pulls it from the bones and thins them. Vitamin D helps the body absorb that calcium, and Harvard Health says few foods contain it, which gives sardines another point. Diet is only part of the picture: Harvard Health adds that daily weight-bearing exercise, such as brisk walking and weight training, limiting alcohol and not smoking round out the best plan for healthy bones.

There is a planet-friendly case as well. Harvard Health says aquatic foods generate far fewer greenhouse gas emissions than land-based foods, and because farm-raised fish are fed grain plus fish meal made from small fish, eating the small fish directly is an even better choice. Tufts calls canned sardines and salmon generally sustainable picks and notes that canned fish keeps a long time on the shelf, so a quick healthy meal is always within reach. Canning does damage fragile nutrients such as vitamin C, Tufts says, but most of the healthy ingredients in fish come through unscathed.

This is general information, not medical advice, so talk to your doctor if a medical condition limits which foods you can eat.