Mackerel or sardine: which is healthier?

Full comparison · Protein · Calories · Healthier

Neither food is healthier in every way. Per 3.5 oz (100 g), here is where mackerel and sardine differ against FDA Daily Values, so you can choose for what you need more or less of.

Mackerel

More of: vitamin b12 (792% vs 372% DV), magnesium (23% vs 9% DV), vitamin a (6% vs 4% DV).
Also more of what the FDA treats as nutrients to limit: saturated fat (21% vs 8% DV).

Sardine

More of: calcium (29% vs 1% DV), iron (16% vs 9% DV).
Also more of what the FDA treats as nutrients to limit: cholesterol (47% vs 25% DV), sodium (13% vs 4% DV).

Beyond the nutrient table

Health effects depend on more than composition: how much you eat, what it replaces, and the studies on each food. These pages grade that evidence:

What the numbers don't tell you

Start with the label. Mackerel covers more than one fish, and the FDA and EPA put King mackerel on their Choices to Avoid list, the highest-mercury group. FDA testing of 90 sardine samples found a mean of 0.013 ppm mercury. We have no such figure for Atlantic mackerel.

On this page, canned Atlantic sardines with bone carry 382 mg of calcium per 3.5 oz (100 g), against 15 mg in cooked Atlantic mackerel. Raw sardine flesh has 50 mg in UK tables, so the bones do the work. The can also brings sodium, 307 mg against 83 mg.

In Lima retail markets, 75% of mackerel bought after 2 p.m. carried more than 10 ppm of histamine (illness is usually tied to over 500 ppm). In supervised tests, some batches of spoiled mackerel caused nausea, vomiting or diarrhea at 50 g. FDA says histamine builds up in poorly chilled fish and heating doesn't remove it. Buy early and keep it cold.

For raw or marinated fish, brining and pickling reduce parasites but don't eliminate them. Freezing at -4 °F (-20 °C) or below for 7 days kills them, and we can't say a home freezer gets there. If you're pregnant or feeding a child, FDA advises fish cooked to a safe internal temperature.

Sardines are the simpler weekly pick. With mackerel, check the species.

Evidence behind this note

Level E The word mackerel covers fish on opposite sides of the US advice: the FDA and EPA chart lists King mackerel under Choices to Avoid, the group named for the highest mercury levels, while Atlantic mackerel sits under Best Choices. US FDA and EPA, Advice about Eating Fish, fish chart
Level E FDA testing of 90 sardine samples found a mean mercury level of 0.013 ppm (median 0.010, maximum 0.083). US FDA, Mercury Levels in Commercial Fish and Shellfish (1990-2012), content current as of 02/25/2022
Level E Canned sardines eaten with their soft bones carry 500 to 679 mg of calcium per 3.5 oz (100 g) in the UK table, against 50 mg in raw flesh. CoFID 2021, Public Health England, OGL v3.0, codes 16-424, 16-440, 16-401
Level C Histamine builds up in mackerel that is kept warm, and in Lima retail markets 75 percent of mackerel bought after 2 p.m. carried more than 10 ppm against the 500 ppm usually tied to illness. J Food Prot, 2009
Level C Blind feeding of spoiled mackerel showed that 1.8 oz (50 g) portions can set off vomiting or diarrhea, and that volunteers fell into susceptible and non-susceptible groups rather than reacting in step with the histamine dose. Food Addit Contam, 1991
Level E The FDA warns that histamine in poorly chilled fish cannot be removed by washing, freezing or heating, so cooking fish into soup does not make spoiled fish safe. US FDA, FDA Issues Final Compliance Policy Guide on Scombrotoxin (Histamine)-Forming Fish and Fishery Products, 2024
Level E FDA guidance says brining and pickling reduce but do not eliminate parasites in fish, while freezing at -20°C (-4°F) for 7 days, or at -35°C (-31°F) until solid and then 15 hours, does kill them. FDA, Fish and Fishery Products Hazards and Controls Guidance, Chapter 5: Parasites
Level E The FDA advises pregnant women to eat fish only cooked to a safe internal temperature, so raw or marinated sardines are out. FDA/EPA, Questions and Answers on Advice about Eating Fish, content current as of 02/17/2022

Written from the studies and agency guidance we hold for both foods, reviewed by the Bioma editorial system. How we verify.

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Where the numbers come from

Mackerel: USDA FoodData Central, Fish, mackerel, Atlantic, cooked, dry heat, FDC ID 175120 · full profile · all forms of mackerel
Sardine: USDA FoodData Central, Fish, sardine, Atlantic, canned in oil, drained solids with bone, FDC ID 175139 · full profile · all forms of sardine

Each food is one USDA entry, chosen as it is usually eaten. Other cuts, brands and preparations differ; the links show them. % DV uses FDA Daily Values for adults. How we verify.