Choosing the right types of fish to eat is essential for maximising nutritional benefits whilst ensuring safety and sustainability. Fish provides high-quality protein, omega-3 fatty acids (EPA and DHA), vitamin D, iodine, selenium, and B vitamins that support cardiovascular health, brain function, and overall wellbeing. The NHS recommends at least two portions of fish weekly, including one oily variety. Understanding which fish offer the greatest health advantages, how much to consume, and which species to limit—particularly during pregnancy—helps you make informed dietary choices that align with UK guidance and environmental responsibility.

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, and minerals that support multiple aspects of human health. The omega-3 fatty acids found in fish—particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—play important roles in cardiovascular health, brain function, and inflammatory regulation. These long-chain polyunsaturated fatty acids cannot be efficiently synthesised by the human body and must be obtained through dietary sources, making fish consumption particularly important.

Regular fish consumption has been associated with reduced risk of coronary heart disease, stroke, and cardiac mortality according to NHS and SACN (Scientific Advisory Committee on Nutrition) guidance. The potential cardioprotective effects may result from multiple mechanisms, including reduction of plasma triglycerides, decreased platelet aggregation, improved endothelial function, and modest reductions in blood pressure. The NHS recommends fish as part of a balanced diet for overall health.

Beyond cardiovascular health, fish provides excellent sources of vitamin D, iodine, selenium, and B vitamins (particularly B12). Vitamin D is essential for bone health and immune function, whilst iodine supports thyroid hormone production. The high-quality protein in fish contains all essential amino acids required for tissue repair and maintenance. For pregnant women, adequate omega-3 intake supports foetal neurodevelopment, though certain fish should be avoided due to mercury content. Pregnant women should also avoid fish liver and cod liver oil supplements due to high vitamin A content, which may harm the unborn baby.

The anti-inflammatory properties of omega-3 fatty acids may offer some benefit for certain inflammatory conditions such as rheumatoid arthritis, though evidence varies by condition. Patients should discuss dietary changes with their GP, particularly if taking anticoagulant medications, as high-dose omega-3 supplements (not typical dietary fish consumption) may theoretically affect bleeding risk in some cases.

Best Types of Fish to Eat for Nutrition

When selecting fish for optimal nutritional benefit, understanding the distinction between oily fish and white fish is essential. Oily fish contain omega-3 fatty acids distributed throughout their flesh and are the primary dietary source of EPA and DHA. White fish, whilst still nutritious, contain lower levels of omega-3 fats, with these nutrients concentrated mainly in the liver.

Oily fish varieties recommended for regular consumption include:

• Salmon – Rich in omega-3s, vitamin D, and selenium. Both wild and farmed salmon provide substantial nutritional benefits, though wild varieties typically contain slightly higher omega-3 levels.

• Mackerel – One of the richest sources of omega-3 fatty acids, also providing vitamin B12 and selenium.

• Sardines and pilchards – Excellent omega-3 sources that are also rich in calcium when consumed with bones. These smaller fish accumulate less mercury than larger species.

• Herring – Provides substantial omega-3 content along with vitamin D and B12.

• Trout – Particularly rainbow trout, offers good omega-3 levels and is widely available in the UK.

It's worth noting that whilst fresh tuna is considered an oily fish, canned tuna is not classified as oily fish because the canning process reduces the omega-3 content.

White fish options include:

• Cod and haddock – Lean protein sources with minimal fat, rich in selenium and vitamin B12.

• Plaice and sole – Mild-flavoured flatfish providing quality protein with low fat content.

• Sea bass and sea bream – Versatile white fish offering good protein and mineral content, though pregnant women should limit consumption due to potential pollutant levels.

For pregnant women, those trying to conceive, and young children, the NHS advises avoiding shark, swordfish, and marlin entirely due to elevated mercury levels, which can affect neurological development. Other adults should limit these high-mercury fish to no more than one portion per week. Pregnant women and those trying to conceive should also limit tuna to no more than two fresh steaks or four medium cans weekly. Some white fish with potentially higher pollutant levels (such as sea bass, sea bream, halibut, turbot and rock salmon/dogfish) should also be limited during pregnancy.

How Much Fish Should You Eat Weekly

The NHS recommends that adults consume at least two portions of fish per week, with one portion being oily fish. A standard portion is defined as approximately 140 grams (cooked weight). This recommendation aligns with guidance from Public Health England and is designed to optimise the health benefits of fish consumption whilst minimising potential risks from environmental contaminants.

For oily fish specifically, most adults can safely consume up to four portions weekly. However, certain populations require modified guidance. Girls, women who might become pregnant, pregnant women, and breastfeeding mothers should limit oily fish consumption to no more than two portions per week due to potential accumulation of pollutants that could affect foetal development. These same groups should avoid shark, swordfish and marlin entirely.

Boys and men can consume up to four portions of oily fish weekly without concern, as they do not face the same reproductive health considerations. For most white fish, there are no specific upper limits for consumption, as these varieties are generally low in environmental contaminants. However, some white fish species (such as sea bass, sea bream, halibut, turbot and rock salmon/dogfish) may contain higher levels of pollutants and should be limited during pregnancy.

It is important to note that these recommendations represent minimum targets rather than maximum limits for most fish types. Many individuals in the UK consume less fish than recommended, missing out on valuable nutritional benefits. If you have specific health conditions—particularly bleeding disorders, are taking anticoagulant medications (such as warfarin), or have fish allergies—you should discuss appropriate fish consumption with your GP or a registered dietitian. Those on anticoagulants should be aware that high-dose omega-3 supplements (not typical dietary fish) may require monitoring.

For individuals who do not consume fish due to dietary preferences or allergies, alternative omega-3 sources include flaxseeds, chia seeds, and walnuts, which provide alpha-linolenic acid (ALA). Algae-based supplements are also available, which provide DHA and sometimes EPA directly (similar to fish oil), making them suitable plant-based alternatives.

If you experience any suspected side effects from medicines or food supplements (including omega-3 products), report them to the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk.

Choosing Sustainable Fish Options in the UK

Sustainable fish consumption ensures that marine ecosystems remain healthy for future generations whilst maintaining fish stocks at viable levels. In the UK, several certification schemes and resources help consumers make environmentally responsible choices when purchasing fish.

The Marine Stewardship Council (MSC) blue label indicates that fish has been sourced from certified sustainable fisheries that meet strict environmental standards. This certification considers fish stock health, ecosystem impact, and fishery management effectiveness. Similarly, the Aquaculture Stewardship Council (ASC) certifies responsibly farmed fish, addressing concerns about farming practices, environmental impact, and fish welfare.

The Marine Conservation Society's Good Fish Guide provides regularly updated ratings for fish species based on sustainability, helping UK consumers make informed choices. This resource categorises fish as:

• Best choice (green-rated) – Fish from well-managed, sustainable sources

• OK (amber-rated) – Acceptable options with some sustainability concerns

• Fish to avoid (red-rated) – Species from overfished stocks or caught using damaging methods

When shopping, consider these sustainable practices:

• Choose line-caught fish over trawled varieties when possible, as this method generally causes less ecosystem damage

• Consider British-caught fish such as mackerel, herring, and mussels, which are often available locally

• Select lesser-known species like dab, pouting, or gurnard, reducing pressure on popular stocks

• Purchase from fishmongers who can provide information about sourcing and fishing methods

For farmed fish, look for organic certification or ASC labels, which indicate higher welfare standards and reduced environmental impact. Scottish salmon, when responsibly farmed, represents a sustainable choice widely available in UK supermarkets.

It's worth noting that smoked and salted fish products can be high in salt, which may be a consideration for those monitoring their sodium intake for cardiovascular health.

If you have concerns about fish consumption related to existing health conditions or medications, consult your GP. For general dietary advice incorporating sustainable fish choices, NHS resources and registered dietitians can provide personalised guidance suitable for your individual health needs.

Frequently Asked Questions