Why Is Fish Oil No Longer Recommended? What the Research Found

Fish oil is "no longer recommended" in one specific sense: high-dose omega-3 capsules are not advised as a heart preventive for everyone, and in the UK they never were. The NHS advice has not changed: at least two portions of fish a week, one oily. The headline came from a 2024 UK Biobank cohort study: regular fish-oil users without heart disease had 13% more new atrial fibrillation, users with heart disease progressed less, and no dose was recorded.¹ The randomised trials are more precise: at about 1 g a day omega-3 did not reduce major cardiovascular events; at 4 g a day purified EPA cut events by a quarter and EPA plus DHA did nothing; and atrial fibrillation risk rises with dose, about 50% above 1 g a day and about 12% at 1 g or less.^{2, 3, 4, 5, 6, 7}

• What changed: an atrial fibrillation cost above 1 g a day; neutral supplement-dose trials on major events
• What did not change: two portions of fish a week, one oily (NHS); 450 mg a day from food (SACN)
• Who still has a reason: no oily fish, pregnancy, high triglycerides (with a doctor), vegans via algal oil

Sources checked on 29 October 2026.

Is fish oil no longer recommended? What UK bodies say

Nothing was withdrawn, because nothing was recommended: the NHS says a healthy diet includes at least two portions of fish a week, one oily; and makes no recommendation of fish oil capsules for healthy adults.⁸ SACN's 2004 advice set the UK figure at about 450 mg a day of long-chain omega-3, what two portions of fish supply, as a food target with no supplement recommendation.⁹ The GB register still authorises the wording that EPA and DHA contribute to the normal function of the heart, at 250 mg a day: a maintenance statement, not a promise to lower risk.¹⁰ The Wellgard omega-3 guide has the intake picture.

Why do cardiologists say stop fish oil?

For one of three reasons. First, the 2020 STRENGTH trial: 4 g a day of EPA plus DHA in statin-treated heart patients was stopped for futility.⁶ Second, the 2021 meta-analysis of the large trials, which found a dose-related rise in new atrial fibrillation.⁷ Third, the 2024 cohort, widely read as proof of harm though it could establish neither cause nor dose.¹ A cardiologist telling a patient with a rhythm disorder to stop a 4 g prescription is following the evidence; it says little about a healthy adult taking 300 mg.

What did the big trials find?

Doses are EPA plus DHA unless stated.^{2, 3, 5, 6, 11, 12}

At supplement doses the trials were neutral but not empty: VITAL's fall in heart attacks and the Cochrane review's 9% fall in coronary events are small and consistent; deaths and strokes did not move.⁴

Does fish oil cause atrial fibrillation, and at what dose?

At high doses, yes; at label doses the signal is small. Across seven cardiovascular trials in 81,210 people, those given omega-3 were about 25% more likely to develop atrial fibrillation; the risk was about 50% higher in trials using more than 1 g a day and about 12% higher at 1 g or less.⁷ VITAL Rhythm, the one large trial at a supplement dose, gave 840 mg a day to 25,119 adults for five years: 3.7% against 3.4%, not significant.¹² Anyone with atrial fibrillation or heart disease should ask their cardiologist before taking more than 1 g a day; is there any danger when taking omega-3 covers who should ask first.

Does fish oil raise bleeding risk?

Not in surgery. A review of 52 publications found fish oil reduced platelet clumping in the laboratory but did not increase surgical bleeding or transfusions, and saw no need to stop it before an operation; VITAL's five years at 840 mg produced no excess bleeding.^{2, 13} At 4 g of prescription EPA, serious bleeding was 2.7% against 2.1%, short of significance.⁵ Tell your surgeon what you take; on warfarin or another anticoagulant, tell your GP or anticoagulant clinic and keep the daily amount steady.

Who still has reason to take omega-3, and how much?

Someone who eats no oily fish gets only tens of milligrams of EPA and DHA a day from food, against the 250 mg behind the register's heart wording and SACN's 450 mg; a supplement at 250 mg to 1 g a day closes that gap.^{9, 10} In pregnancy the register's maternal wording applies at 200 mg of DHA a day on top of the adult 250 mg, omega-3 reduced early preterm birth from 4.6% to 2.7% across 70 trials, and the NHS says avoid fish liver oil for its vitamin A.^{8, 10, 14} High triglycerides are the 2 to 4 g case, under a doctor. Vegans and people with a fish allergy use algal oil; how to get enough omega-3 on a vegan diet has the amounts. General use sits under 1 g a day; EFSA's safety ceiling is 5 g, and how much omega 3-6-9 do I need daily has the label table.¹⁵

Does this apply to algae omega-3 and flaxseed oil?

By dose, yes. Algal DHA is the same molecule as fish DHA (600 mg a day raised blood DHA as much as cooked salmon), so an algal product at a label dose sits in the 1 g or less band where VITAL Rhythm found no significant excess.^{12, 16} Flaxseed oil is a different fat, ALA, of which most adults convert only about 5% to EPA and under 1% to DHA, so the fish-oil trials are not about it.¹⁸ A flaxseed-oil 3-6-9 capsule states its ALA, to be read against the 2 g a day behind the register's ALA cholesterol wording, and contains no EPA or DHA; an algal gummy or capsule states its DHA, against the 250 mg behind the brain and vision wording.¹⁰

What we don't know

Why the two 4 g trials disagree is unsettled: purified EPA against mineral oil cut events, EPA plus DHA against corn oil did not, and no head-to-head trial exists.^{5, 6} The cohort behind the headline recorded no dose, so how much of its 13% is the capsules and how much the people who chose them is unknown.¹ The meta-analysis excluded trials in people who already had atrial fibrillation, so a label dose in them is untested.⁷

Frequently asked questions

Should I stop taking fish oil, and can I stop suddenly?

At 1 g or less a day with no rhythm condition, nothing in the trials says stop; above 1 g, decide with a doctor; if it was prescribed, stopping is the prescriber's call. There is no withdrawal: blood EPA and DHA drift back to diet levels over weeks because the body stores little.¹⁷ Should omega-3 be taken daily has the dosing evidence.

Is fish oil good for you?

At 250 mg a day EPA and DHA carry the register's heart-function wording and DHA the brain and vision wording; in trials, triglycerides fell about 15% and coronary events about 9%.^{4, 10}

Should I stop taking fish oil if I have high cholesterol?

Omega-3 lowers triglycerides, not LDL cholesterol; keep any prescribed statin and ask your GP about the capsule.⁴

Sources

1. Chen G, et al. Regular use of fish oil supplements and course of cardiovascular diseases. BMJ Medicine, 2024. Prospective cohort, 415,737 UK Biobank participants, median 11.9 years; charity-funded (Gates Foundation). PubMed 38800667.
2. Manson JE, et al. Marine n-3 fatty acids and prevention of cardiovascular disease and cancer (VITAL). New England Journal of Medicine, 2019. Randomised trial, 25,871 adults, median 5.3 years; publicly funded (NIH). PubMed 30415637.
3. ASCEND Study Collaborative Group. Effects of n-3 fatty acid supplements in diabetes mellitus. New England Journal of Medicine, 2018. Randomised trial, 15,480 adults with diabetes, mean 7.4 years; charity-funded (British Heart Foundation and others). PubMed 30146932.
4. Abdelhamid AS, et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews, 2020. Cochrane review, 86 trials, 162,796 people; non-commercial funding. PubMed 32114706.
5. Bhatt DL, et al. Cardiovascular risk reduction with icosapent ethyl for hypertriglyceridemia (REDUCE-IT). New England Journal of Medicine, 2019. Randomised trial, 8,179 statin-treated patients, median 4.9 years; manufacturer-funded. PubMed 30415628.
6. Nicholls SJ, et al. High-dose omega-3 fatty acids vs corn oil and major adverse cardiovascular events (STRENGTH). JAMA, 2020. Randomised trial, 13,078 statin-treated patients, stopped early; manufacturer-funded. PubMed 33190147.
7. Gencer B, et al. Marine omega-3 supplementation and the risk of atrial fibrillation. Circulation, 2021. Meta-analysis, 7 trials, 81,210 people, 4.9 years; publicly funded (NIH). PubMed 34612056.
8. NHS. Fish and shellfish. Page last reviewed 26 June 2026. nhs.uk.
9. SACN. Advice on fish consumption: benefits and risks. Published 1 December 2004. gov.uk.
10. Great Britain nutrition and health claims (NHC) register. Page last updated 19 May 2026. gov.uk.
11. Kalstad AA, et al. n-3 fatty acid supplements in elderly patients after myocardial infarction (OMEMI). Circulation, 2021. Randomised trial, 1,014 patients aged 70 to 82, 2 years; funding not stated on PubMed. PubMed 33191772.
12. Albert CM, et al. Marine omega-3 fatty acid and vitamin D supplementation and incident atrial fibrillation (VITAL Rhythm). JAMA, 2021. Randomised trial, 25,119 adults, median 5.3 years; publicly funded (NIH). PubMed 33724323.
13. Begtrup KM, et al. No impact of fish oil supplements on bleeding risk. Danish Medical Journal, 2017. Systematic review, 52 publications; funding not stated on PubMed. PubMed 28552094.
14. Middleton P, et al. Omega-3 fatty acid addition during pregnancy. Cochrane Database of Systematic Reviews, 2018. Cochrane review, 70 trials, 19,927 women; non-commercial funding. PubMed 30480773.
15. EFSA. EFSA assesses safety of long-chain omega-3 fatty acids. Published 27 July 2012. efsa.europa.eu.
16. Arterburn LM, et al. Algal-oil capsules and cooked salmon: nutritionally equivalent sources of DHA. Journal of the American Dietetic Association, 2008. Randomised open-label trial, 32 adults, 2 weeks; manufacturer-funded. PubMed 18589030.
17. Arterburn LM, et al. Distribution, interconversion and dose response of n-3 fatty acids. American Journal of Clinical Nutrition, 2006. Review; funding not stated on PubMed. PubMed 16841856.
18. Plourde M, Cunnane SC. Extremely limited synthesis of long chain polyunsaturates in adults. Applied Physiology, Nutrition, and Metabolism, 2007. Review; funding not stated on PubMed. PubMed 17622276.

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This article is general information, not medical advice. If you have a heart rhythm condition, take an anticoagulant, have been prescribed an omega-3 medicine or are planning surgery, speak to your GP, cardiologist or pharmacist before starting or stopping an omega-3 supplement.