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Vitamins and minerals

Omega-3 and cod liver oil — do they really protect the heart and brain?

Sources: 9 · Article: 11 821 characters

Henryk Różański links omega-3 to heart benefits, while Paul Clayton says commercial fish oil does not protect.

  • Paul Clayton points to protection from eating oily fish and a lower cardiovascular risk with a higher omega-3 index.
  • Paul Clayton cautions that commercial fish oils have no documented benefits of this kind, and their oxidation may promote atrial fibrillation.
  • On the brain, Andrzej Frydrychowski says fats are very important, but does not state directly that omega-3 or cod liver oil protects it.

What the authors write

Henryk Różański

Omega-3 fatty acids counter atherosclerosis and reduce the risk of heart attack and embolism.

„Omega-3 fatty acids counter atherosclerosis and reduce the risk of heart attack and embolism. They ease the symptoms of acne, psoriasis, and rheumatic diseases. They enhance the effects of anti-inflammatory and antirheumatic drugs. The recommended daily dose is 800 mg of EPA and 500 mg of DHA.”Kwasy omega-3 działają przeciwmiażdżycowo, zmniejszają ryzyko wystąpienia zawału i zatoru. Łagodzą objawy trądziku, łuszczycy i chorób reumatycznych. Nasilają działanie leków przeciwzapalnych i przeciwreumatycznych. Zalecana dawka dzienna EPA wynosi 800 mg, natomiast DHA 500 mg.
witasteryna F, czyli witamina F
Paul Clayton

Eating oily fish has been linked to protection from heart disease and stroke, but such protection has not been attributed to lean fish or commercial fish oil.

„These reports on amphiphilic polyphenols and omega-3 fatty acids are broadly consistent with the Zutphen studies (36–39) and others, which found that eating oily fish protected against heart disease and stroke, whereas lean fish and commercial fish oil did not, because they contain no polyphenols or phlorotannins (40–43).”Te raporty o polifenolach amfifilowych i kwasach omega-3 są zasadniczo zgodne z badaniami Zutphen (36–39) i innymi, które wykazały, że jedzenie tłustych ryb chroniło przed chorobami serca i udarem, podczas gdy chude ryby i handlowy olej rybny przed nimi nie chroni, gdyż nie zawiera polifenoli i florotanin (40–43).
Dieta a nasze przeznaczenie
Paul Clayton

A higher omega-3 index has been linked to a lower risk of cardiovascular disease and a longer life.

„This is also consistent with a new dataset from the Framingham Offspring Cohort (44), in which people with a higher omega-3 index had a significantly lower risk of cardiovascular disease and longer life expectancy than those with a lower omega-3 index.”Jest to również zgodne z nowym zestawem danych z Framingham Offspring Cohort (44), w którym osoby z wyższym indeksem omega-3 wykazały znacznie zmniejszone ryzyko chorób sercowo-naczyniowych i wydłużoną długość życia w porównaniu z osobami z niższym indeksem omega-3.
Dieta a nasze przeznaczenie
Paul Clayton

Paul Clayton considers that commercial and pharmaceutical fish oils do not provide the documented benefits attributed to oily fish or omega-3 combined with polyphenols.

„But there is another way of looking at this. Given that commercial and pharmaceutical fish oils do NOT provide the documented benefits of oily fish or omega-3 fatty acids combined with amphiphilic polyphenols (62–68), I suspect that the null/negative results reflect the fish oil industry's decision to replace the originally beneficial phlorotannins in fish oil with an unsuitable antioxidant, d-alpha-tocopherol [vitamin E – translator's note]. This formula error makes the omega-3 fatty acids consumed vulnerable to oxidation in the body, resulting in lower secondary bioavailability (69), and suggests increased formation of lipid peroxidation products—some of which appear to be profibrillatory [contributing to the onset of atrial fibrillation – translator's note.”Ale jest inny sposób patrzenia na to.Biorąc pod uwagę, że komercyjne i farmaceutyczne oleje rybie NIE dają udokumentowanych korzyści płynących z tłustych ryb lub kwasów omega-3 w połączeniu z amfifilowymi polifenolami (62–68), podejrzewam, że zerowe/ujemne wyniki odzwierciedlają decyzję przemysłu produkującego tran rybi o zastąpieniu pierwotnie dobroczynnych florotanin zawartych w oleju rybim z nieodpowiednim przeciwutleniaczem, d-alfa-tokoferolem [witaminą E – przyp. tłum.].Ten błąd w recepturze powoduje, że spożywane kwasy omega-3 są podatne na utlenianie w organizmie, co objawia się niższą biodostępnością drugorzędową (69) i sugeruje zwiększone tworzenie produktów peroksydacji lipidów – z których niektóre wydają się być profibrylacyjne [przyczyniające się do wystąpienia migotania przedsionków – przyp.
Twoje oszukane serce
Paul Clayton

Paul Clayton suspects that oxidation of omega-3 fatty acids after consumption may increase the formation of products that promote atrial fibrillation.

„translator's note]. This formula error makes the omega-3 fatty acids consumed vulnerable to oxidation in the body, resulting in lower secondary bioavailability (69), and suggests increased formation of lipid peroxidation products—some of which appear to be profibrillatory [contributing to the onset of atrial fibrillation – editor's note] (70–72). Polyphenols have their own antiarrhythmic properties (73), which may prevent atrial fibrillation (74).”tłum.].Ten błąd w recepturze powoduje, że spożywane kwasy omega-3 są podatne na utlenianie w organizmie, co objawia się niższą biodostępnością drugorzędową (69) i sugeruje zwiększone tworzenie produktów peroksydacji lipidów – z których niektóre wydają się być profibrylacyjne [przyczyniające się do wystąpienia migotania przedsionków – przyp. red.] (70–72).Polifenole mają własne właściwości antyarytmiczne (73), które mogą zapobiegać migotaniu przedsionków (74).
Twoje oszukane serce
Andrzej Frydrychowski

Omega-3 fatty acids have anti-inflammatory effects.

„Omega-3s have anti-inflammatory effects, which we very much want. Omega-6s are found in sunflower, grape-seed, and corn oils, as well as animal meat and dairy products. They are essential for health, provided their proportions remain equal to those of omega-3s.”Omegi 3 wykazują działanie przeciwzapalne, na którym nam tak bardzo zależy. Omegi 6 występują w: oleju słonecznikowym, z pestek winogron, kukurydzianym, mięsie zwierząt i produktach mlecznych. Są one niezbędne dla zdrowia pod warunkiem zachowania ich równych proporcji z omegami-3.
Czy tłuszcze są nam niezbędne?
Andrzej Frydrychowski

Andrzej Frydrychowski stresses that the quality of fat matters for the brain, but does not identify omega-3 or cod liver oil as a way to protect the brain.

„For the brain to function properly, not only the amount of fat in the diet but, above all, its quality is extremely important. The nervous system needs saturated, monounsaturated, and polyunsaturated fats, as well as cholesterol, to function properly.”Niezwykle istotna dla prawidłowej pracy mózgu jest nie tylko ilość tłuszczu spożywanego w diecie, ale przede wszystkim jego jakość. Do prawidłowej pracy układu nerwowego potrzebne są tłuszcze: nasycone, jednonienasycone, tłuszcze wielonienasycone oraz cholesterol.
Czy tłuszcze są nam niezbędne?

Research from PubMed · Europe PMC

We selected 4 studies with the best, positive results. This is a selection, not a full review of all research.

Total number of studies on this topic in PubMed: 406.

A meta-analysis found that high doses of omega-3 taken for at least a year improved ejection fraction and exercise capacity in people with heart failure.

Aim of the study: Heart failure is a progressive condition associated with a high mortality rate. Despite advancements in treatment, many patients continue to experience less-than-ideal outcomes.

Results: No significant differences were found in dropout rates or all-cause mortality between the n-3 PUFAs and control groups. Long-term, high-dose n-3 PUFA supplementation, particularly with a predominance of docosahexaenoic acid or eicosapentaenoic acid, enhances cardiac function in patients with heart failure without increasing risk of adverse events. Further well-designed RCTs with long treatment durations (i.e., >1 y) and stringent heart failure inclusion criteria are necessary to confirm these findings and reduce potential biases. This trial was registered at PROSPERO as CRD42024590476.

The Optimal Dosage and Duration of ω-3 PUFA Supplementation in Heart Failure Management: Evidence from a Network Meta-Analysis. · Adv Nutr 2025
Money for the studynot stated
Do the authors have ties to companies?yes — the authors reported it
Did a manufacturer help with the study?NO
Type of studycombined analysis of many studies (meta-analysis)

“Not stated” does not mean nobody paid — the database does not always record it.

A meta-analysis of cohort studies linked higher intake of long-chain omega-3s to a lower risk of stroke, although the association differed between groups.

Aim of the study: We performed a meta-analysis to clarify the relationship between long chain n-3 polyunsaturated fatty acid (PUFA) intake and stroke risk. Relevant studies were identified by searching online databases through May 2015.

Results: The pooled RR of overall stroke risk for long chain n-3 PUFA intake was 0.87 [95% confidence interval (CI), 0.79-0.95]. Stratification analysis showed that higher long chain n-3 PUFAs intake was associated with reduced fatal stroke risk (RR = 0.84; 95% CI, 0.73-0.97), reduced stroke risk for BMI < 24 (RR = 0.86; 95% CI, 0.75-0.98) and reduced stroke risk for females (RR = 0.81; 95% CI, 0.71-0.92), but was not associated with stroke risk for either BMI ≥ 24 or men. This meta-analysis reveals that higher long chain n-3 PUFA intake is inversely associated with risk of stroke morbidity and mortality with BMI and sex as key factors influencing this risk. Individuals should be encouraged to manage their body weight while increasing their intake of long chain n-3 PUFAs.

BMI Affects the Relationship between Long Chain N-3 Polyunsaturated Fatty Acid Intake and Stroke Risk: a Meta-Analysis. · Sci Rep 2015
Money for the studygovernment, public institutions · National Natural Science Foundation of China, Postdoctoral Fund, National Basic Research Program of China
Do the authors have ties to companies?no — the authors say so
Did a manufacturer help with the study?NO
Type of studycombined analysis of many studies (meta-analysis)

“Not stated” does not mean nobody paid — the database does not always record it.

A meta-analysis of clinical trials found that omega-3 lowered some heart-failure-related markers, but did not generally improve ejection fraction or clinical outcomes.

Aim of the study: Many new clinical trials about the effect of omega-3 polyunsaturated fatty acids (PUFAs) in heart failure (HF) patients have shown inconsistent results. Therefore, a meta-analysis of randomised controlled trials (RCTs) was performed to determine the benefits of omega-3 PUFAs in HF patients.

Results: A total of nine RCTs involving 800 patients were eligible for inclusion. Compared with patients taking placebo, HF patients who received omega-3 PUFAs experienced decreased brain natriuretic peptide levels and serum norepinephrine levels. Although the left ventricular ejection fraction (LVEF) and clinical outcomes (Tei index, peak oxygen consumption) did not improve, subgroup analysis showed that the LVEF increased in dilated cardiomyopathy (DCM) patients. Overall, omega-3 PUFA supplements might be beneficial in HF patients, especially in DCM patients, but further studies are needed to confirm these benefits.

The Role of Omega-3 Polyunsaturated Fatty Acids in Heart Failure: A Meta-Analysis of Randomised Controlled Trials. · Nutrients 2016
Money for the studynot stated
Do the authors have ties to companies?no — the authors say so
Did a manufacturer help with the study?NO
Type of studycombined analysis of many studies (meta-analysis)

“Not stated” does not mean nobody paid — the database does not always record it.

An umbrella review found that higher fish intake may be linked to a lower risk of acute coronary syndrome, but evidence on other heart and brain conditions is limited.

Aim of the study: Fish represents one of the most important dietary sources of omega-3 polyunsaturated fatty acids, which are known to be associated with various health benefits. This study aimed to systematically review existing meta-analyses of observational studies exploring the association between fish intake and various health outcomes.

Results: This study aimed to systematically review existing meta-analyses of observational studies exploring the association between fish intake and various health outcomes. A systematic search of electronic databases was conducted to retrieve a total of 63 studies. Evidence was deemed as possible for the association between higher fish intake and decreased risk of the acute coronary syndrome, liver cancer, and depression, and limited for other outcomes (including age-related macular degeneration, Alzheimer's disease, heart failure, all-cause and coronary heart disease mortality, total and ischaemic stroke) due to heterogeneity between results and potential otherwise inexplicable confounding factors. In conclusion, results from epidemiological studies support the mechanistic effects associated with omega-3 fatty acids from high fish consumption, but evidence needs to be further corroborated with more reliable results.

Fish and human health: an umbrella review of observational studies. · Int J Food Sci Nutr 2022
Money for the studynot stated
Do the authors have ties to companies?not stated
Did a manufacturer help with the study?unknown
Type of studyreview of many studies

“Not stated” does not mean nobody paid — the database does not always record it.

Perspectives and opinion materials

The content below presents the authors’ opinions, interpretations and hypotheses. It is not treated as equal to scientific studies and systematic reviews.

Orthomolecular Medicine News Service Opinion material
„Adequate doses of both omega-3 (in flax oil, walnuts, fish) and omega-6 (in seed oils such as canola, soybean, peanut) fatty acids are essential for health. Although essential, omega-6 fatty acids are thought to contribute to inflammation throughout the body whereas omega-3 fatty acids are anti-inflammatory. Omega-3 fatty acids are essential for most body organs including the brain but are found in lower levels than omega-6 fatty acids in most vegetables.”Adequate doses of both omega-3 (in flax oil, walnuts, fish) and omega-6 (in seed oils such as canola, soybean, peanut) fatty acids are essential for health. Although essential, omega-6 fatty acids are thought to contribute to inflammation throughout the body whereas omega-3 fatty acids are anti-inflammatory. Omega-3 fatty acids are essential for most body organs including the brain but are found in lower levels than omega-6 fatty acids in most vegetables.
Omega 3 Fatty Acids and Cardiovascular Disease

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