Essential fatty acids (EFAs) are vital nutrients your body cannot produce, making dietary intake crucial for health. The two primary EFAs—alpha-linolenic acid (ALA, an omega-3) and linoleic acid (LA, an omega-6)—support cell membrane structure, brain function, and cardiovascular health. Understanding which foods provide these nutrients helps you achieve a balanced fatty acid profile. This guide explores the best UK food sources of essential fatty acids, recommended daily intakes aligned with NHS and SACN guidance, signs of deficiency, and practical strategies to incorporate omega-3 and omega-6 into your everyday diet for long-term wellbeing.

What Are Essential Fatty Acids and Why Do You Need Them?

Essential fatty acids (EFAs) are polyunsaturated fats that your body cannot synthesise and must therefore be obtained through diet. The two primary essential fatty acids are alpha-linolenic acid (ALA), an omega-3 fatty acid, and linoleic acid (LA), an omega-6 fatty acid. From these essential fatty acids, the body can produce longer-chain derivatives—such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from ALA, and arachidonic acid (AA) from LA—which play critical roles in cellular function and signalling.

Essential fatty acids are integral components of cell membranes throughout the body, influencing membrane fluidity, receptor function, and cellular communication. They are particularly concentrated in the brain and retina, where DHA is important for cognitive development and visual function. Beyond structural roles, these fatty acids are metabolised into bioactive lipid mediators called eicosanoids, which regulate inflammation, immune responses, blood clotting, and vascular tone.

Adequate intake of essential fatty acids supports overall health. EPA and DHA contribute to normal heart function, as recognised by the European Food Safety Authority (EFSA) at intakes of 250mg per day. DHA also contributes to the maintenance of normal brain function and vision at the same daily intake. These fatty acids may help maintain healthy blood triglyceride levels when consumed in sufficient amounts.

The balance between omega-3 and omega-6 intake is considered important, as both families compete for the same metabolic enzymes. Modern Western diets tend to be higher in omega-6 relative to omega-3. Understanding which foods provide these nutrients is the first step towards achieving a healthier fatty acid profile and supporting long-term wellbeing.

Best Food Sources of Omega-3 and Omega-6 Fatty Acids

Omega-3 fatty acids are found in both marine and plant-based sources, though their forms differ. Oily fish—such as salmon, mackerel, sardines, and herring—are the richest sources of the long-chain omega-3s EPA and DHA, which are readily utilised by the body. Fresh tuna counts as an oily fish, but tinned tuna does not due to the processing methods that remove oils. The NHS recommends consuming at least two portions of fish per week, of which one should be oily fish (approximately 140g per portion). For those who do not consume fish, marine algae supplements can provide a vegetarian source of DHA, though not all provide EPA.

Plant-based sources provide ALA, the shorter-chain omega-3 that the body can partially convert to EPA and DHA, though conversion efficiency is limited (typically less than 10%). Good plant sources include flaxseeds (linseeds), chia seeds, walnuts, hemp seeds, and rapeseed oil. Ground flaxseeds are particularly versatile and can be added to porridge, smoothies, or baked goods to boost omega-3 intake.

Omega-6 fatty acids are more abundant in the typical UK diet. Primary sources include vegetable oils such as sunflower oil, corn oil, and soybean oil, as well as products made with these oils. Nuts and seeds—including almonds, cashews, sunflower seeds, and pumpkin seeds—also provide linoleic acid. Poultry, eggs, and wholegrain cereals contribute smaller amounts. Evening primrose oil and borage oil are concentrated sources of gamma-linolenic acid (GLA), a specific omega-6 fatty acid.

While omega-6 fatty acids are essential, most people in the UK consume adequate or even excessive amounts relative to omega-3. Prioritising omega-3-rich foods, particularly oily fish and plant sources like flaxseeds and walnuts, can help improve your essential fatty acid profile. Choosing rapeseed oil over oils higher in omega-6 for cooking is another practical strategy to increase omega-3 intake.

How Much Essential Fatty Acids Do You Need Daily?

The UK does not have specific Dietary Reference Values (DRVs) for total essential fatty acids, but guidance exists for individual fatty acid types. The Scientific Advisory Committee on Nutrition (SACN) and the British Nutrition Foundation provide recommendations based on evidence for health.

For omega-3 fatty acids, SACN recommends adults consume at least 450mg of EPA plus DHA daily. This equates to approximately one to two portions of oily fish per week. Most adults should not exceed four portions of oily fish weekly. Pregnant and breastfeeding women should aim for similar intakes to support foetal and infant development, though they should limit oily fish to two portions weekly due to potential pollutant exposure. Pregnant women should also avoid shark, swordfish, and marlin, limit tuna due to mercury concerns, and avoid fish liver oils due to high vitamin A content.

For ALA (the plant-based omega-3), the European Food Safety Authority (EFSA) sets an Adequate Intake of approximately 0.5% of total energy, which translates to about 1-1.5g daily for an average adult consuming 2,000 calories. This can be achieved through a tablespoon of ground flaxseeds or a small handful of walnuts.

Omega-6 fatty acids as linoleic acid (LA) have a minimum requirement of about 1% of total energy to prevent deficiency. However, EFSA recommends an Adequate Intake of approximately 4% of total energy, equating to roughly 8-10g daily for most adults. Given the prevalence of vegetable oils and processed foods in modern diets, most people in the UK easily meet or exceed this requirement.

Rather than focusing on specific ratios of omega-6 to omega-3, UK dietary guidance emphasises achieving adequate intakes of both types, with particular attention to increasing omega-3 consumption. Individuals following vegan or vegetarian diets should pay particular attention to ALA sources and may consider algae-based DHA supplements to ensure adequate long-chain omega-3 status. If considering supplements during pregnancy, discuss this with your midwife or GP first.

Signs of Essential Fatty Acid Deficiency

True essential fatty acid deficiency is rare in the UK and typically occurs only in specific clinical contexts, such as prolonged total parenteral nutrition without lipid supplementation, severe malabsorption syndromes (e.g., short bowel syndrome, cystic fibrosis), or extremely restrictive diets. However, suboptimal intake—particularly of omega-3 fatty acids—is more common.

Classical signs of EFA deficiency include dermatological manifestations such as dry, scaly, or flaky skin, particularly affecting the extremities. The skin may appear rough and develop a characteristic "phrynoderma" or "toad skin" appearance. Hair may become dry, brittle, and prone to breakage. In severe cases, poor wound healing and increased susceptibility to infections may occur due to impaired immune function and compromised skin barrier integrity.

In infants and children, essential fatty acid deficiency can impair growth and development. Symptoms may include failure to thrive and developmental concerns, reflecting the important role of DHA in brain and retinal development. Infants with unexplained scaly dermatitis or failure to thrive should receive prompt medical attention.

Some research has explored associations between omega-3 status and various health parameters, including inflammatory markers and cognitive function. However, these relationships are complex, and individual responses vary considerably. It is important not to attribute non-specific symptoms solely to fatty acid status without proper clinical assessment.

If you suspect essential fatty acid deficiency, particularly in the context of chronic digestive conditions, restrictive eating patterns, or unexplained dermatological symptoms, consult your GP. While routine testing for fatty acid profiles is not typically available in primary care, your GP can assess your diet and underlying conditions, referring to specialists if needed. Management typically involves dietary modification to increase intake of omega-3-rich foods, and in clinical deficiency states, supplementation under medical supervision may be warranted.

Incorporating Essential Fatty Acids Into Your UK Diet

Achieving adequate essential fatty acid intake is straightforward with practical dietary strategies tailored to UK food availability and culinary traditions. The emphasis should be on increasing omega-3 consumption whilst maintaining adequate omega-6 intake.

Prioritise oily fish: Aim for at least one portion weekly of salmon, mackerel, sardines, or herring as part of the NHS recommendation for two portions of fish weekly. Fresh, frozen, and tinned varieties of these fish all count as oily fish, but note that tinned tuna does not count as an oily fish (though fresh tuna does). Most adults should not exceed four portions of oily fish weekly. Tinned sardines on wholegrain toast, grilled mackerel with vegetables, or a salmon fillet with new potatoes are simple, nutritious meals. For sustainability, choose fish certified by the Marine Stewardship Council (MSC) where possible.

Add plant-based omega-3 sources daily: Sprinkle ground flaxseeds (one to two tablespoons) onto breakfast cereals, porridge, or yoghurt. Flaxseeds must be ground to release their nutrients, as whole seeds pass through the digestive system intact. Include a small handful of walnuts as a snack or chopped into salads. Chia seeds can be soaked to make puddings or added to smoothies.

Choose cooking oils wisely: Replace oils high in omega-6 (such as sunflower or corn oil) with rapeseed oil, which has a more favourable fatty acid profile and is suitable for cooking at moderate temperatures. Extra virgin olive oil, whilst lower in omega-3, is an excellent choice for dressings and lower-heat cooking due to its monounsaturated fat content and polyphenols.

Consider fortified foods: Some UK products, including certain eggs, spreads, milk, and yoghurts, are fortified with omega-3 fatty acids. Check labels for EPA and DHA content if you do not regularly consume oily fish.

Supplementation: If dietary intake is insufficient—particularly for vegetarians, vegans, or those with fish aversions—omega-3 supplements may be appropriate. Algae-based supplements provide DHA and sometimes EPA without fish-derived ingredients. Food supplements in the UK are regulated under food law by the Food Standards Agency and Trading Standards. Choose products with clear labelling of EPA and DHA content. Discuss supplementation with your GP or a pharmacist, especially if you take anticoagulant medications or are preparing for surgery, as high-dose omega-3 may affect blood clotting. Pregnant women should avoid fish liver oil supplements due to their high vitamin A content.

If you experience any side effects from supplements, you can report them through the MHRA Yellow Card scheme.

By making these simple adjustments, you can optimise your essential fatty acid intake, supporting overall health within the context of a balanced UK diet.

Frequently Asked Questions