Superfood: Oily Fish
This article is part of the Nutrition & Diet library.
Oily, or fatty fish — including salmon, trout, mackerel, sardines, herring, and anchovies — are defined by their higher fat content compared to white fish. Specifically, it’s the long-chain omega-3 fatty acids.
These fats are largely absent from typical Western diets and difficult to obtain in meaningful amounts from other foods.
Unlike white fish (like cod, flatfish, or tilapia), which primarily store fat in their liver, oily fish distribute fat throughout their flesh. This is how they provide a reliable and concentrated source of omega-3s in a normal portion size.
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Omega-3s
Oily fish stand out, nutritionally, because they supply two omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are difficult to find elsewhere.
While small amounts of omega-3s are found in some plant foods, these do not provide the same compounds or benefits.
Because EPA and DHA are not efficiently produced by the body and are uncommon in most foods, oily fish represent one of the most efficient ways to increase intake through diet alone.
Some plant foods, such as flaxseed, walnuts, and chia seeds, contain another omega-3 called alpha-linolenic acid (ALA).
While ALA is beneficial by itself, the body converts it into EPA and DHA very inefficiently. As a result, relying on plant sources alone typically leads to low levels of EPA and DHA.
For most people, oily fish remain the most practical dietary source of these fats.
Health Effects
EPA and DHA are incorporated into cell membranes throughout the body, where they help control inflammation, brain health and cardiovascular health.
Regular consumption of oily fish is associated with a lower risk of cardiovascular disease and major cardiovascular events such as heart attack and stroke, even at relatively modest intakes. These benefits appear strongest in people with low baseline omega-3 intake.
DHA is also a major structural component of the brain. It makes up a large proportion of the polyunsaturated fats found in brain tissue and plays a role in maintaining normal brain structure, brain function and brain health.
Higher intakes of oily fish have been associated with better cognitive performance in older adults and a lower risk of cognitive decline, dementia, and Alzheimer’s disease.
Researchers believe these effects are partly due to substances derived from EPA and DHA that help protect brain cells from damage and support brain cell maintenance over time.
Additional Benefits
In addition to omega-3s, oily fish also provide a range of other nutrients and health benefits. A typical 100g (3.5 oz) serving of oily fish can provide: 50-100% of your vitamin D, 20–25 grams (1 oz) of high-quality protein, vitamin B12, niacin and selenium.
Smaller species, such as sardines and anchovies, are often eaten with their soft, edible bones, which provide calcium.
How Much Do You Need?
Recommendations vary slightly, but most suggest eating fish at least twice per week, with at least one serving being oily fish.
In practical terms, this equates to 200–250 grams (7–9 ounces) of fish per week. Most oily fish provide 1.3–2.5 grams of EPA and DHA per 100 grams, meaning that even one or two servings per week can substantially increase omega-3 intake.
How to Increase Your Intake
1. Canned Options
Fresh fish can be expensive and difficult to prepare, but canned sardines, salmon, and mackerel are affordable, shelf-stable, and ready-to-eat.
For a quick snack, canned sardines in olive oil can be mashed onto whole-grain crackers with lemon juice and black pepper, or they can be tossed with pasta, capers, and roasted tomatoes.
Canned salmon can be used to make fish cakes if you aren’t a massive fan of the flavour of oily fish. Mix with breadcrumbs, egg, herbs and other flavours, then pan-fry or bake until golden.
2. Keep it Simple
If you’re comfortable with fresh fish, put it on top of your favourite roast vegetables. Bake fillets of salmon, trout, or mackerel at 400°F (200°C) for 8–15 minutes (depending on how big the fillets are). Serve with a sauce made of yoghurt, dill, and lemon.
To cover the flavour of oily fish, you can marinate them in olive oil, garlic, and herbs, hours before cooking.
3. Make it a Staple
Make oily fish a regular event. “Fish Friday” is a household tradition around the world. Kippers, smoked salmon, or mackerel can be eaten for breakfast at the weekend. Tinned tuna or sardines on toast can be a mid-week lunch.
Keep a rotating menu of three simple fish recipes you've mastered and alternate between them.
Consider batch-cooking: cook multiple portions at once, then use throughout the week: in salads, in tacos, wraps or sandwiches or alongside different grains and vegetables. Oily fish is delicious fridge-cold or room temperature.
The Bottom Line
Oily fish are one of the most efficient dietary sources of EPA and DHA — two nutrients that are difficult to obtain elsewhere, which are consistently linked to good cardiovascular and brain health.
While there are issues around access, cost, and taste, using canned fish, simple recipes, and combining oily fish with other strong complementary flavours can help you get more of them into your diet.
N.b. This article is for informational purposes only and is not medical advice. Please consult a qualified healthcare provider before making health decisions. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.