The heart and its normal function matter to many people who pay attention to their diet. Omega-3 fatty acids — particularly EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) from marine sources — are among the most intensively researched nutrients in nutritional science. In this article we set out what the authorised EFSA health claim on normal heart function says and what individual studies report — factually, with no promises of healing or protection. This article is for information only and is not medical advice.
TL;DR — Key points
- The only authorised EFSA health claim relating to the heart is: "EPA and DHA contribute to the normal function of the heart" — from 250 mg EPA+DHA per day (EU Regulation No. 432/2012).
- The REDUCE-IT trial (8,179 patients, 4.9 years) examined a prescription-only, highly purified EPA medicine at 4 g/day — a pharmaceutical context that cannot be transferred to dietary supplements.
- A meta-analysis of 127,477 participants (Hu et al., 2019) observed a dose-response relationship in the trial data analysed; how conclusive and transferable individual studies are is a matter of scientific debate.
- Physiological mechanisms of EPA and DHA under discussion include effects on triglyceride levels, inflammatory mediators, blood pressure and the electrical stability of the heart — these are subjects of research, not authorised proof of effect.
- "Normal heart function" in the sense of the EFSA claim means maintaining a physiologically normal function — not the prevention or treatment of cardiovascular disease.
EPA and DHA contribute to the normal function of the heart with a daily intake of 250 mg EPA+DHA (EFSA). Whether you reach that is shown by your Omega-3 Index.
Test & prices →The EFSA health claim: normal heart function
Following extensive evidence review, the EFSA assessed the following health claim for omega-3 fatty acids, which is authorised in the EU: EPA and DHA contribute to the normal function of the heart. This claim applies from a minimum intake of 250 mg EPA+DHA per day. This is approximately the amount found in one portion of oily fish (e.g. salmon or mackerel, 100–150 g).
EFSA health claim: heart function
According to the EFSA, EPA and DHA contribute to the normal function of the heart. Authorised minimum intake: 250 mg EPA+DHA per day. Foods or dietary supplements may carry this claim if they provide at least 250 mg EPA+DHA per daily serving. (EU Regulation No. 432/2012)
It is important to understand: a health claim describes a physiologically normal function — it is not a therapeutic claim. "Normal heart function" means that sufficient EPA and DHA should be available so that the heart can perform its normal tasks. Those who eat little fish can cover their needs with high-quality fish oil or algae oil supplements.
The REDUCE-IT trial: a pharmaceutical context
Important context: REDUCE-IT did not examine an over-the-counter dietary supplement but a prescription-only medicine (icosapent ethyl, brand name Vascepa) at a high dose in selected high-risk patients. The study results reported below are science reporting and do not constitute a statement that an omega-3 dietary supplement prevents or treats disease or lowers your personal risk of disease.
Few omega-3 studies have attracted as much attention in recent years as the REDUCE-IT trial (Reduction of Cardiovascular Events with Icosapent Ethyl–Intervention Trial). This double-blind, randomised, placebo-controlled study was published in 2019 in the New England Journal of Medicine.
Study design and participants
REDUCE-IT studied 8,179 patients over a median period of 4.9 years. Inclusion criteria: all participants had elevated triglyceride levels (135–499 mg/dL) despite statin therapy and either established cardiovascular disease or at least one additional risk factor (e.g. diabetes mellitus plus at least one additional risk factor). Half the patients received 4 g daily of icosapent ethyl (highly purified EPA ethyl ester), the other half a placebo (mineral oil).
Results: 25% reduction in cardiovascular endpoints
The result was remarkable: the treatment group showed a 25% reduction in the primary endpoint (combined cardiovascular endpoint) versus placebo (hazard ratio 0.75; 95% CI 0.68–0.83; p < 0.001). The primary endpoint included non-fatal myocardial infarction, non-fatal stroke, cardiovascular death, coronary revascularisation and unstable angina.
Further important results from REDUCE-IT:
- Cardiovascular death: fell from 5.2% (placebo) to 4.3% (EPA)
- Non-fatal myocardial infarction: significantly reduced (HR 0.69)
- Stroke: also significantly reduced (HR 0.72)
- Coronary revascularisation: HR 0.65
REDUCE-IT: cardiovascular endpoints with icosapent ethyl (4 g/day EPA)
Double-blind, randomised trial with 8,179 patients over 4.9 years. Administration of 4 g/day of pure EPA showed a 25% reduction in primary cardiovascular endpoints (HR 0.75; 95% CI 0.68–0.83; p < 0.001). Cardiovascular death fell from 5.2% to 4.3%. NNT (number needed to treat) over 4.9 years: 21 patients.
REDUCE-IT has triggered an important debate: part of the scientific community is discussing whether the mineral oil placebo in the control group may have had negative effects and thus artificially widened the difference between the groups. This point has not been conclusively resolved scientifically.
Nevertheless, the FDA approved icosapent ethyl (Vascepa) as the first omega-3 medicine for reducing the risk of cardiovascular events, on the basis of REDUCE-IT.
Meta-analysis of 127,477 participants: dose-response relationship
While a high-risk population was studied in REDUCE-IT, a large-scale meta-analysis by Hu et al. (JAHA 2019) provides a broader picture. The authors — Yu Hu, Frank B. Hu and JoAnn E. Manson from the Harvard T.H. Chan School of Public Health — analysed 13 randomised controlled trials with a total of 127,477 participants.
Central result: dose-response relationship
The meta-analysis found that marine omega-3 supplementation significantly reduced the risk of several cardiovascular endpoints:
- Myocardial infarction: significant risk reduction observed
- Coronary heart disease death: significantly reduced
- Total CVD events: significantly reduced
- Stroke: not statistically significant in the overall group
Of particular note: the analysis showed a dose-response relationship — higher omega-3 doses were associated with a greater risk reduction. An increase in the omega-3 dose of 1 g/day was associated with a significant reduction in myocardial infarction risk.
Cardiovascular risk: 13 randomised trials with 127,477 participants
Marine omega-3 supplementation significantly reduced the risk of myocardial infarction (RR 0.92; 95% CI 0.86–0.98), coronary heart disease death (RR 0.92; 95% CI 0.86–0.98) and total CVD events. A dose-response relationship was observed: higher omega-3 doses showed a greater risk reduction. Per 1 g/day of additional omega-3 intake: significantly reduced myocardial infarction risk.
Context: the evidence on marine omega-3 fatty acids and cardiovascular endpoints is mixed. Some large randomised trials found no significant benefit, while meta-analyses such as the one described here reported effects. Such study results apply to the populations and doses examined in each case and do not allow the general conclusion that a dietary supplement lowers your personal cardiovascular risk. The only authorised health claim relating to the heart remains the EFSA claim on normal heart function.
Mechanisms: how does omega-3 act on the cardiovascular system?
The cardiovascular effects of EPA and DHA are attributed to various mechanisms that have been investigated in numerous experimental and clinical studies:
Triglyceride-lowering effect
EPA and DHA inhibit hepatic VLDL synthesis and increase the beta-oxidation of fatty acids in the liver. At doses from 2 g/day EPA+DHA, studies observe significant triglyceride reductions. At 4 g/day, studies show reductions of over 30% (more in the article Lowering triglycerides with omega-3).
Inflammation modulation
EPA and DHA serve as precursors of anti-inflammatory lipid mediators (resolvins, protectins, maresins). They also displace arachidonic acid (AA) from cell membranes, which reduces the formation of pro-inflammatory prostaglandins and leukotrienes. Chronic inflammation is regarded as a key factor in the development and progression of atherosclerotic plaques.
Blood pressure effects
Research describes vasodilatory effects of EPA and DHA and a possible influence on endothelial function. There is a separate EFSA health claim for blood pressure ("EPA and DHA contribute to the maintenance of normal blood pressure"), which is tied to a considerably higher intake of 3,000 mg EPA+DHA per day and refers to maintaining normal blood pressure — not to the treatment of high blood pressure (more in the article Omega-3 and normal blood pressure).
Influence on the electrical stability of the heart
Experimental studies describe that EPA and DHA can influence cardiac ion channels (particularly sodium channels). In the scientific literature, this mechanism is discussed as one of several possible explanations for observations from the REDUCE-IT drug trial. These are research hypotheses, not authorised proof of effect.
Effects on platelets and thrombosis risk
EPA and DHA can modulate platelet aggregation and reduce the formation of thrombogenic thromboxanes (thromboxane A2), while favouring the formation of prostacyclin (vasodilatory, antiaggregatory). In theory, this may influence the risk of thrombotic events.
Overview: omega-3 intakes, EFSA health claims and study context
| Intake EPA+DHA/day | EFSA status | Study results | Note |
|---|---|---|---|
| 250 mg | Health claim | Normal heart function | EFSA-authorised minimum |
| 500–1,000 mg | No claim of its own | General intake recommendation | Recommendation for the general population (DGE, AHA) |
| 2,000 mg | Health claim | Normal triglyceride levels (separate EFSA claim) | EFSA claim on triglycerides from 2,000 mg |
| 3,000 mg | Health claim | Normal blood pressure (separate EFSA claim) | EFSA claim on blood pressure from 3,000 mg |
| 4,000 mg (EPA) | Medicine | Prescription-only EPA medicine (REDUCE-IT); not a dietary supplement | Only under medical supervision in high-risk patients |
Who should think about a good omega-3 supply?
Whether additional intake makes sense depends on your individual situation and, where a condition already exists, belongs in the hands of a doctor. The following points summarise the contexts in which omega-3 is studied particularly closely in research:
People who keep an eye on their blood lipid levels
For the maintenance of normal triglyceride levels there is a separate EFSA health claim, which is tied to an intake of 2,000 mg EPA+DHA per day. Details can be found in the article Triglycerides and omega-3. Where a lipid metabolism disorder already exists, the doctor decides on the appropriate approach.
People under medical care
Intervention trials such as REDUCE-IT were conducted specifically in selected patient groups using a high-dose medicine. These results concern the medical and therapeutic field and cannot be transferred to over-the-counter dietary supplements or to the general population. Decisions on measures for an existing cardiovascular risk are made solely by the treating doctor.
People who eat little fish
The omega-3 index (proportion of EPA+DHA in erythrocyte fatty acids) is used in research as a long-term biomarker of supply. People who eat little fish often have low readings and can supplement their intake with oily fish or supplements to contribute to a normal supply. Physically active people also often pay attention to a good omega-3 status; EPA and DHA are studied in this connection, for example in the context of recovery after training.
What dietary guidelines say about intake
Nutrition societies provide guidance on general intake. The American Heart Association (AHA) recommends oily fish around twice a week for the general population. Prescription-only, high-dose omega-3 medicines, by contrast, are reserved for medical indications and are prescribed by a doctor. The EFSA names 250 mg EPA+DHA per day as an adequate intake for adults (EFSA Journal 2010;8(3):1461); the German Nutrition Society (DGE) recommends fish once or twice a week (DGE 2024).
Fish oil vs. algae oil: does the source make a difference?
Both fish oil and algae oil provide EPA and DHA. Fish contain these fatty acids because they eat algae and tiny marine organisms — algae oil is therefore the direct, vegan source.
Bioavailability matters for your supply: in studies, omega-3 in triglyceride form (TG form, as is usual in high-quality fish oil and algae oil) tends to show better bioavailability than the ethyl ester form. REDUCE-IT used icosapent ethyl in ethyl ester form — and the results were nonetheless clear. For a detailed assessment, see our article on omega-3 quality.
Practical tips for optimal absorption
There are a few practical pointers to help your body absorb EPA and DHA well:
Take it with a meal containing fat
The bioavailability of omega-3 increases markedly when it is taken together with a meal that naturally contains fat. Studies show 50–70% higher absorption compared with taking it on an empty stomach.
Pay attention to oxidation protection
Rancid omega-3 supplements deliver oxidised fatty acids, which can be counterproductive. A fresh, neutral smell and the presence of tocopherols (vitamin E) as an antioxidant are indicators of quality. A quick smell test by opening a capsule can help.
Regularity is key
In studies, a stable omega-3 status only builds up with continuous intake over months; sporadic intake barely changes the omega-3 index to a measurable degree. How much omega-3 per day makes sense depends on your diet and situation — it is best to discuss this with your doctor if you are unsure.
Frequently asked questions
What does the EFSA health claim on 250 mg EPA+DHA per day state?
The EFSA health claim "EPA and DHA contribute to the normal function of the heart" is authorised from an intake of 250 mg EPA+DHA per day (EU Regulation No. 432/2012). This claim describes the maintenance of a normal physiological function and is not a statement about the prevention or treatment of disease. Clinical intervention trials such as REDUCE-IT used considerably higher amounts of high-dose, prescription-only EPA (up to 4 g/day) and cannot be transferred to dietary supplements. It is best to discuss questions about your individual intake with your doctor.
Is omega-3 a substitute for cholesterol-lowering medications?
No. Omega-3 fatty acids have no relevant effect on LDL cholesterol and are not a substitute for statins or other lipid-lowering medications. They complement drug therapy — as in REDUCE-IT, where all participants were already taking statins. Any change to ongoing medication must only be made in consultation with a doctor.
What omega-3 dose was used in REDUCE-IT?
In REDUCE-IT, pure EPA (icosapent ethyl) was used at a dose of 4 g per day — split into two doses of 2 g in the morning and evening. This was highly purified EPA without any DHA, in ethyl ester form. This dose is considerably higher than typical everyday supplementation and should only be taken under medical supervision.
Does REDUCE-IT apply to people without heart disease?
Only high-risk patients took part in REDUCE-IT: established CVD, or diabetes plus additional risk factors, together with elevated triglycerides despite statins. The results cannot simply be extrapolated to the general population. For primary prevention in otherwise healthy people, the EFSA points to the basic claim from 250 mg EPA+DHA daily, which supports normal heart function.
Is there an omega-3 test to know one's own status?
Yes. The so-called omega-3 index measures the proportion of EPA+DHA in red blood cells (erythrocyte membranes) and is used in research as a long-term biomarker. In observational studies, values below 4% are classed as low and values above 8% as high; such an index is a measured value and not a diagnosis. Several providers offer home test kits (e.g. OmegaQuant, Zinzino); you can find an overview of omega-3 index tests on our test page. Your doctor can also order the test through a laboratory and interpret the values.
Important note on bleeding time
High-dose omega-3 supplements (from approximately 3 g/day) can prolong bleeding time. If you take anticoagulants (e.g. warfarin, direct oral anticoagulants) or have planned surgery, be sure to inform your doctor. According to the EFSA, intakes of up to around 5 g EPA+DHA per day are safe for adults (EFSA Journal 2012;10(7):2815); the German Federal Institute for Risk Assessment (BfR) advises not to exceed 1.5 g per day from all sources (BfR FAQ, as of 30.04.2026). Higher amounts only after consulting your doctor.
Related articles
Within the topic of heart and circulation there are two further EFSA health claims, each with its own intake condition. The most relevant related articles:
- Omega-3 and normal blood pressure — EFSA health claim from 3,000 mg/day and the research
- Omega-3 and normal triglyceride levels — EFSA health claim from 2,000 mg/day
- Omega-3 for older adults — normal heart function and supply in later life
- All health topics on omega-3 — overview of all areas
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Medical disclaimer
This article is for general information and does not replace medical advice, diagnosis or treatment. The only authorised health claim relating to the heart for omega-3 is the EFSA health claim "EPA and DHA contribute to the normal function of the heart" (from 250 mg EPA+DHA per day). The studies cited serve as scientific context; they are not a statement that omega-3 dietary supplements prevent, treat or cure cardiovascular disease or lower your personal risk of disease. Dietary supplements are not a substitute for a balanced diet and a healthy lifestyle. People with cardiovascular disease or an existing medication plan should discuss any supplementation with their doctor beforehand and should not change ongoing medication on their own initiative.