Mackerel and sardines are both small, oily fish prized for their omega-3 content and sustainability credentials, and while they’re often recommended interchangeably, a few real differences are worth knowing.
| Nutrient | Mackerel | Sardines |
|---|---|---|
| Calories | 205 kcal | 208 kcal |
| Protein | 18.6 g | 24.62 g ✓ |
| Total Carbohydrate | 0 g | 0 g |
| Dietary Fiber | 0 g | 0 g |
| Total Sugars | 0 g | 0 g |
| Total Fat | 13.9 g | 11.45 g |
| Saturated Fat | 3.26 g | 1.53 g ✓ |
| Sodium | 90 mg ✓ | 307 mg |
Notable compounds in each
When to choose each
Reach for mackerel when sodium is a concern, particularly if you’re buying fresh or frozen rather than tinned. Reach for sardines for more protein and calcium gram for gram — tinned sardines eaten with their soft bones are one of the few whole-food sources of calcium that doesn’t come from dairy. Both deliver a strong dose of vitamin B12, vitamin D and selenium, and both are widely considered among the more sustainable fish choices.
Common questions
Why is tinned fish sodium so much higher than fresh? Tinning typically adds salt (or brine/oil) as part of preservation, so a tinned sardine or mackerel figure reflects that, while a fresh fillet doesn’t. Draining and rinsing tinned fish reduces it somewhat.
Are mackerel and sardines low in mercury? Yes — as small, short-lived fish low on the food chain, both are considered among the lowest-mercury oily fish choices, unlike larger predatory fish such as swordfish or shark.
Nutrition values are USDA FoodData Central approximations — see our editorial approach for how we source and verify data.