Choosing the best fish to eat for health involves understanding which species offer the greatest nutritional benefits whilst balancing safety considerations. Oily fish such as salmon, mackerel, sardines, and herring provide the highest concentrations of omega-3 fatty acids—essential nutrients linked to cardiovascular health, cognitive function, and reduced inflammation. NHS guidance recommends consuming at least two portions of fish weekly, with one being oily fish, to optimise health benefits. This article examines the healthiest fish options, UK consumption guidelines, and practical strategies for incorporating fish safely into your diet.

Why Fish Is Important for Your Health

Fish represents one of the most nutritionally valuable food groups available, offering a unique combination of high-quality protein, essential vitamins, minerals, and omega-3 fatty acids. Regular fish consumption has been associated with several potential health benefits, including reduced cardiovascular disease risk, with some evidence suggesting benefits for cognitive function and metabolic health. The omega-3 polyunsaturated fatty acids found in fish—particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—play important roles in cellular membrane structure, inflammatory regulation, and neurological development.

From a cardiovascular perspective, omega-3 fatty acids may help reduce triglyceride levels, lower blood pressure modestly, and might contribute to heart rhythm regulation. NHS and NICE guidance recognises the value of fish consumption as part of a healthy diet, particularly for secondary prevention after myocardial infarction, though it's important to note that NICE does not recommend omega-3 supplements for primary or secondary prevention. The anti-inflammatory properties of omega-3s may also benefit individuals with certain inflammatory conditions, though evidence varies across different disease states.

Beyond omega-3 content, fish provides excellent bioavailable protein with all essential amino acids, making it valuable for muscle maintenance and repair. Oily fish is also a good source of vitamin D (particularly important in the UK where sunlight exposure is limited), and most fish provide vitamin B12, iodine, and selenium—nutrients essential for thyroid function, immune health, and neurological wellbeing. The combination of these nutrients, alongside relatively low saturated fat content in most species, positions fish as a valuable component of healthy dietary patterns.

For pregnant women and young children, adequate omega-3 intake may support foetal brain development and visual function, though these benefits must be balanced against considerations regarding mercury content and sustainability, which UK public health guidance addresses specifically.

Healthiest Fish Options: Omega-3 and Nutrient Content

Oily fish contain the highest concentrations of omega-3 fatty acids and represent the most nutritionally beneficial choices for health. The primary oily fish recommended in UK dietary guidance include:

• Salmon (wild or farmed): Excellent source of EPA and DHA, typically providing approximately 1.5–2.5g omega-3 per 100g serving, though values vary by species, season and farming methods. Also rich in vitamin D, B vitamins, and selenium. Farmed salmon typically contains higher fat content than wild varieties.

• Mackerel: One of the richest sources of omega-3 (approximately 2–3g per 100g), alongside high vitamin B12 and vitamin D content. Atlantic mackerel is commonly available in UK markets.

• Sardines and pilchards: Provide substantial omega-3 (approximately 1.5–2g per 100g) and are particularly valuable as they contain edible bones, offering excellent calcium content. Their position lower in the food chain means reduced mercury accumulation.

• Herring: Good omega-3 profile (approximately 1.5–2g per 100g), with vitamin D and selenium content. Often available fresh, smoked, or pickled.

• Trout (particularly rainbow trout): Moderate to high omega-3 content (approximately 0.5–1.5g per 100g), with excellent protein quality and vitamin B12.

White fish such as cod, haddock, plaice, and sole contain less fat overall and therefore lower omega-3 levels (typically 0.1–0.3g per 100g). However, they remain excellent protein sources with minimal saturated fat, making them valuable for overall dietary balance. They provide good levels of iodine, selenium, and B vitamins.

Shellfish including mussels, oysters, and crab offer moderate omega-3 content alongside exceptional mineral profiles, particularly zinc, iron, and selenium. Mussels are particularly sustainable and nutrient-dense.

It's important to note that tuna (fresh or canned) does not count as an oily fish in UK dietary recommendations, despite containing some omega-3 fatty acids.

When selecting fish, fresh, frozen, and canned options all retain nutritional value effectively. For canned fish, those in olive oil retain omega-3s but some may be lost if the oil is drained. Products in water maintain protein content with lower calories, while those in brine may have higher sodium levels (rinsing can help reduce this).

UK Guidelines on Fish Consumption

The NHS and UK Scientific Advisory Committee on Nutrition (SACN) recommend that adults consume at least two portions of fish per week, with one portion being oily fish. A standard portion is approximately 140g cooked weight. This recommendation balances the cardiovascular and nutritional benefits of fish consumption against potential risks from environmental contaminants.

For the general adult population, there are no upper limits on white fish consumption, but oily fish intake should be moderated due to potential pollutant accumulation. Men, boys, and women past childbearing age can safely consume up to four portions of oily fish weekly. The restriction relates primarily to persistent organic pollutants and dioxins that accumulate in fatty tissues, though levels in UK fish supplies are monitored by the Food Standards Agency (FSA) and Committee on Toxicity (COT) and are generally low.

Pregnant women, those planning pregnancy, breastfeeding mothers, and girls should limit oily fish to no more than two portions weekly due to potential mercury and pollutant exposure that could affect foetal development. However, fish consumption remains important during pregnancy for omega-3 supply. These groups should avoid certain high-mercury species entirely, including shark, swordfish, and marlin. Tuna consumption should be limited to no more than two fresh tuna steaks (approximately 140g cooked) or four medium cans weekly.

Children benefit significantly from fish consumption for growth and development. Girls should consume up to two portions of oily fish weekly, while boys can have up to four portions. The same high-mercury fish restrictions apply as for pregnant women.

The FSA monitors contaminant levels in UK fish supplies regularly. Sustainability considerations are also important—choosing fish from well-managed stocks supports long-term availability. The Marine Conservation Society's Good Fish Guide provides UK-specific sustainability ratings.

Individuals with fish allergies should avoid relevant species entirely and seek dietetic advice regarding omega-3 supplementation alternatives. Those taking anticoagulant medications should maintain consistent fish intake patterns. While dietary fish consumption is generally safe, high-dose omega-3 supplements may have mild antiplatelet effects, so patients should consult their healthcare provider before starting supplements.

How to Include More Fish in Your Diet Safely

Incorporating fish into your regular dietary pattern can be straightforward with practical planning and varied preparation methods. Practical strategies include:

• Meal planning: Designate specific days as 'fish days' to establish routine consumption. Many people find midweek and weekend meals convenient for fish preparation.

• Stock your freezer: Frozen fish fillets retain nutritional quality excellently and offer convenience. Individually wrapped portions allow flexible meal planning without waste.

• Embrace canned options: Tinned sardines, mackerel, and salmon provide quick, affordable alternatives for sandwiches, salads, or pasta dishes. Choose products in water, olive oil, or tomato sauce rather than brine to control sodium.

• Vary preparation methods: Grilling, baking, poaching, and steaming preserve omega-3 content better than deep frying. Simple seasoning with lemon, herbs, and olive oil enhances flavour without added saturated fat.

Food safety considerations are essential when handling and preparing fish:

• Purchase fish from reputable suppliers with proper refrigeration. Fresh fish should smell mild and oceanic, not strongly 'fishy' or ammonia-like.

• Store fresh fish in the coldest part of your refrigerator (below 5°C), follow use-by dates, and typically consume within 1-2 days, or freeze on the day of purchase.

• Ensure thorough cooking—fish should be piping hot throughout, opaque, and flake easily with a fork.

• Pregnant women can eat raw fish (such as in sushi) if it has been frozen first, as this kills parasites. However, they should avoid raw shellfish completely due to bacterial risks.

• Prevent cross-contamination by using separate chopping boards and utensils for raw fish, and wash hands thoroughly after handling.

For individuals concerned about cost, sardines, mackerel, and frozen white fish offer excellent value whilst maintaining nutritional benefits. Tinned fish provides the most economical option for regular consumption.

If you dislike traditional fish flavours, try milder white fish varieties first, incorporate fish into flavourful dishes like curries or Mediterranean-style preparations, or consider fish cakes and fish pie where texture and taste are modified.

Those unable to consume fish due to allergies, dietary restrictions, or strong aversions should consult their GP or a registered dietitian regarding omega-3 supplementation alternatives, such as algae-derived supplements for vegetarians and vegans. However, whole fish provides additional nutrients beyond omega-3s that supplements cannot fully replicate.

Frequently Asked Questions