How much omega-3 per day do you need for optimal health? Omega-3 fatty acids are essential fats that support cardiovascular function, brain health, and inflammatory regulation, yet the body cannot produce them. In the UK, the Scientific Advisory Committee on Nutrition recommends approximately 450 mg daily of EPA and DHA—the most active omega-3 forms—primarily obtained from oily fish. Requirements vary by age, pregnancy status, and health conditions, with some individuals needing higher therapeutic doses under medical supervision. Understanding appropriate omega-3 intake helps ensure you meet your nutritional needs safely and effectively.

Recommended Daily Omega-3 Intake in the UK

Omega-3 fatty acids are essential polyunsaturated fats that the body cannot synthesise, making dietary intake crucial for maintaining health. In the UK, there is no single universally mandated daily requirement for omega-3, as recommendations vary between health organisations and depend on individual circumstances.

The Scientific Advisory Committee on Nutrition (SACN) advises a population average intake of approximately 450 mg per day of combined eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)—the two most biologically active forms of omega-3. The NHS Eatwell Guide recommends consuming at least two portions of fish per week, with one being an oily fish such as salmon, mackerel, or sardines. It's worth noting that fresh tuna counts as oily fish, while tinned tuna does not. These long-chain fatty acids are primarily found in marine sources and play vital roles in cardiovascular health, brain function, and inflammatory regulation.

For alpha-linolenic acid (ALA), a plant-based omega-3 found in flaxseeds, walnuts, and rapeseed oil, the European Food Safety Authority (EFSA) suggests an adequate intake of around 0.5% of total energy intake. For an average adult consuming 2,000 calories daily, this translates to roughly 1.1 grams of ALA. Whilst ALA can be converted to EPA and DHA in the body, this conversion is relatively inefficient (typically less than 10%), making direct sources of EPA and DHA particularly valuable.

It is important to note that these are general population recommendations. Individual requirements may differ based on age, sex, pregnancy status, existing health conditions, and dietary patterns. Vegetarians and vegans, for instance, may need to pay particular attention to omega-3 intake, as they typically rely solely on ALA conversion or algae-based supplements for EPA and DHA.

How Much Omega-3 Do You Need Based on Age and Health?

Omega-3 requirements vary significantly across different life stages and health profiles. Understanding these variations helps ensure adequate intake for optimal physiological function throughout the lifespan.

Infants and children have particularly high omega-3 needs to support rapid brain and visual development. During pregnancy and breastfeeding, maternal DHA intake becomes crucial, as it transfers to the foetus and infant. The EFSA recommends that pregnant and lactating women consume 250 mg of EPA and DHA daily plus an additional 100–200 mg of DHA daily, bringing their total to approximately 350–450 mg per day. The NHS advises pregnant women to eat fish but with important limitations: no more than two portions of oily fish weekly, no more than two tuna steaks or four medium-sized cans of tuna weekly, and to avoid fish liver oil supplements (which contain vitamin A) and high-mercury species like shark, swordfish and marlin. Infant formula in the UK is now routinely fortified with DHA to support neurodevelopment in non-breastfed babies.

For children aged 2–18 years, recommendations scale with body size and energy requirements. School-age children should aim for roughly 250 mg of EPA and DHA daily, achievable through one to two portions of oily fish weekly. Adolescents approaching adult body mass may benefit from adult-level intakes.

Older adults represent another group with potentially different omega-3 needs. Age-related changes in metabolism, increased inflammatory burden, and higher cardiovascular disease risk mean that maintaining adequate omega-3 status becomes particularly important. While some research suggests potential benefits from higher intakes in older adults, there are no official UK recommendations establishing different requirements solely based on age.

Individuals with specific health considerations may require higher intakes under medical supervision. These therapeutic doses should only be undertaken following consultation with a healthcare professional, as they exceed standard nutritional recommendations and may interact with medications such as anticoagulants.

Omega-3 Dosage for Specific Health Conditions

Whilst general population recommendations focus on disease prevention, therapeutic omega-3 supplementation at higher doses may be considered for specific medical conditions, always under appropriate clinical guidance.

Cardiovascular disease: NICE guidance (NG238) does not recommend omega-3 fatty acid compounds for primary or secondary prevention of cardiovascular disease. However, NICE Technology Appraisal 805 recommends icosapent ethyl (a purified EPA-only preparation) at a dose of 4 grams daily for selected high-risk adults with raised triglycerides who are already taking statins and meet specific criteria. This recommendation is based on evidence showing cardiovascular risk reduction in this specific population. Patients should discuss their individual risk profile with their GP or cardiologist.

For hypertriglyceridaemia (elevated blood triglycerides), omega-3-acid ethyl esters are licensed in the UK as an adjunct to diet. The BNF and product SmPC indicate doses of 2–4 grams daily under medical supervision, which can reduce triglyceride levels by 20–50%. These preparations are used alongside dietary measures and, where appropriate, other lipid-lowering medications.

Rheumatoid arthritis and inflammatory conditions may respond to omega-3 supplementation, with studies typically using 2.6–3 grams of EPA and DHA daily. Some patients report reduced joint pain and stiffness, potentially allowing reduction in non-steroidal anti-inflammatory drug (NSAID) use. However, effects are modest and variable, and omega-3 should complement rather than replace conventional disease-modifying therapy.

Emerging evidence explores omega-3's role in mental health conditions including depression and cognitive decline. However, NICE guidelines for depression (NG222) and dementia (NG97) do not currently recommend omega-3 supplements as treatment for these conditions. Patients experiencing mental health symptoms should seek appropriate psychiatric or psychological assessment rather than relying on nutritional interventions alone.

Can You Take Too Much Omega-3? Safety and Upper Limits

Whilst omega-3 fatty acids are essential nutrients, excessive intake can pose health risks, making it important to understand safe upper limits and potential adverse effects.

The European Food Safety Authority (EFSA) has established that supplemental intakes of up to 5 grams of EPA and DHA combined daily are generally safe for the adult population. However, this does not mean such high doses are necessary or advisable for most people. The EFSA also notes that long-term safety data for very high intakes remain limited.

Common adverse effects of omega-3 supplementation, particularly at higher doses, include:

• Gastrointestinal symptoms: Fishy aftertaste, nausea, loose stools, and indigestion are frequently reported, especially with doses exceeding 3 grams daily

• Bleeding risk: Omega-3 fatty acids have mild antiplatelet effects, potentially increasing bleeding tendency. This is particularly relevant for patients taking anticoagulants (warfarin, DOACs) or antiplatelet agents (aspirin, clopidogrel)

• Immune function: Very high doses may suppress certain immune responses, though clinical significance remains uncertain

• Vitamin A and D toxicity: Fish liver oils (such as cod liver oil) contain high levels of these fat-soluble vitamins, and excessive consumption can lead to toxicity. Pregnant women should avoid fish liver oil supplements due to the risk of vitamin A toxicity

Drug interactions warrant particular attention. Patients taking anticoagulant or antiplatelet medications should consult their GP or pharmacist before starting omega-3 supplements, as combined use may increase bleeding risk. Dose adjustments or additional monitoring may be necessary. If you are scheduled for surgery, inform your surgical and anaesthetic team about any omega-3 supplements you are taking; they will advise whether you need to stop them before your procedure.

Contaminants in fish and fish oil products—including mercury, polychlorinated biphenyls (PCBs), and dioxins—represent another safety consideration. Reputable manufacturers employ molecular distillation and testing to minimise contaminant levels. Pregnant women should follow NHS guidance on fish consumption to limit mercury exposure.

When to seek medical advice: Contact your GP if you experience unusual bleeding or bruising, persistent gastrointestinal symptoms, or any concerning effects whilst taking omega-3 supplements. Always inform healthcare professionals about all supplements you are taking. If you suspect side effects from omega-3 supplements, you can report them through the MHRA Yellow Card scheme.

Getting Omega-3 from Food vs Supplements

The optimal approach to meeting omega-3 requirements involves understanding the relative merits of dietary sources versus supplementation, as each has distinct advantages and limitations.

Food sources remain the preferred method for obtaining omega-3 fatty acids for most people. Oily fish—including salmon, mackerel, sardines, herring, and fresh tuna—provide the richest sources of EPA and DHA. A typical 140-gram portion of salmon contains approximately 2.5 grams of omega-3, though content varies by species and preparation method. Beyond omega-3, fish provides high-quality protein, vitamin D, selenium, and iodine, creating a comprehensive nutritional package that supplements cannot replicate.

Plant-based sources of ALA include:

• Flaxseeds and flaxseed oil: Exceptionally rich in ALA (approximately 2.3 grams per tablespoon of ground flaxseed)

• Chia seeds: Contain about 5 grams of ALA per 28 grams (1 ounce)

• Walnuts: Provide roughly 2.5 grams of ALA per 28 grams (1 ounce)

• Rapeseed oil: A practical cooking oil with meaningful ALA content

However, as noted earlier, ALA conversion to EPA and DHA is limited, making these sources less efficient for meeting EPA and DHA requirements specifically.

Omega-3 supplements become particularly relevant for:

• Individuals who do not consume fish due to dietary preferences, allergies, or cultural reasons

• Vegetarians and vegans: Algae-based supplements provide direct EPA and DHA without animal products

• Those requiring therapeutic doses for specific medical conditions

• Pregnant women concerned about mercury exposure from fish, though they should follow NHS guidance on fish consumption and avoid fish liver oil supplements due to vitamin A content

When selecting supplements, consider quality markers such as third-party testing certification, appropriate EPA and DHA content (check labels carefully), and enteric coating to reduce fishy aftertaste. In the UK, most omega-3 supplements are regulated as foods under food law (overseen by the Food Standards Agency), while prescription products like omega-3-acid ethyl esters are regulated as medicines by the MHRA.

Practical recommendations for most adults include consuming two portions of fish weekly (one oily), incorporating plant-based omega-3 sources regularly, and considering supplementation only when dietary intake is consistently inadequate or specific health conditions warrant higher doses. Always discuss supplementation plans with your GP or a registered dietitian, particularly if you have existing health conditions or take regular medications. This integrated approach—prioritising whole foods whilst recognising the role of supplements when appropriate—offers the most balanced strategy for maintaining optimal omega-3 status throughout life.

Frequently Asked Questions