Why do cardiologists say stop fish oil?

The first two things a cardiologist has read, the null outcome trials and the rhythm signal

Why cardiologists say stop fish oil is a question that puzzles a reader who took it for the heart, and the answer is four things a cardiologist has read that a shelf has not, in the order a cardiologist would give them. The first, the outcome trials: the large randomised trials of the last decade gave around a gram a day of EPA and DHA to tens of thousands of people, in primary prevention and in people with diabetes or existing disease, and followed them for years counting heart attacks, strokes and cardiovascular deaths, and found no meaningful reduction, the cardiovascular outcome literature's null at the dose a shelf sells, so a patient who tells a cardiologist they take fish oil for the heart is telling them about a supplement that, in the best trials that will ever be run, did nothing a cardiologist can measure, and a cardiologist who says stop is often saying only that it is pointless. The second, the rhythm signal: the meta-analyses of those same trials found a dose-related increase in atrial fibrillation, most evident at four grams a day and small or absent below a gram, and a cardiologist who spends a working life managing atrial fibrillation, its anticoagulation and its stroke risk, weighs a small rhythm risk against no measurable benefit and finds the arithmetic simple, particularly in a patient who already has a rhythm history, an enlarged atrium, a large endurance training history, or a reason to be on a high dose, so a cardiologist who says stop to a patient on a gram or more is often saying that the one thing the trials found was the wrong way.

The third and fourth things, the guideline and the exception, what a reader told to stop does, what a reader with no cardiologist does, and the four filed

The third, the guideline: NICE's lipid modification guidance says do not offer omega-3 fatty acid compounds for the prevention of cardiovascular disease, in primary or secondary prevention, and do not advise people to take them for that purpose, a position built on the null trials and shared by the European and American cardiology societies for shelf fish oil, so a cardiologist who says stop is following a guideline rather than a hunch, and a patient who reads that omega-3 is good for the heart has read a shelf and not a guideline, the register's heart claim being a nutrition claim about the normal function of a healthy heart at 250mg and not a prevention claim about disease, the distinction the cardiologists-recommend page draws. The fourth, the exception: purified EPA on prescription, four grams a day of icosapent ethyl, reduced cardiovascular events in one large trial in patients with raised triglycerides on a statin, with its own atrial fibrillation signal, and a cardiologist who prescribes it does so for that specific patient at that specific dose, monitored, and says stop the shelf fish oil at the same time because the shelf oil is not the drug, a different molecule at a different dose in a different patient, so the exception explains why a cardiologist can say stop your fish oil and start this one in the same breath. What a reader told to stop does: stops, with nothing to withdraw from, the stopping page's finding that the pool falls silently over months, and tells the cardiologist if they want to keep a standard softgel for the nutrition claim, since a cardiologist's stop is often aimed at the high dose or at the prevention belief rather than at 300mg with dinner, and the cardiologist decides. What a reader with no cardiologist does, a healthy lifter with no heart condition: decides by the oily-fish audit for a nutrition claim that is not prevention, one standard softgel for a low-fish plate and none for oily fish twice a week, without the belief that it prevents anything and without the high dose the rhythm signal belongs to, which is the site's standing instruction and the one a cardiologist would not object to. The four filed: null outcome trials at a gram, a rhythm signal with the dose, a guideline that says do not offer, and a prescription exception that is not the shelf, with the worked example being the nutrition claim's softgel for the reader with no cardiologist and a low-fish plate, £14.99 for 90 at 17p.

The verdict, four things read, an instruction to follow, and an audit for everyone else

Why do cardiologists say stop fish oil: because of four things a cardiologist has read, the large outcome trials in which around a gram a day of EPA and DHA produced no meaningful reduction in heart attacks, strokes or cardiovascular death, the meta-analyses that found a dose-related atrial fibrillation risk most evident at four grams and small or absent below one, the NICE guideline that says do not offer omega-3 for the prevention of cardiovascular disease, and the exception of purified EPA on prescription at four grams for specific patients, which is a drug the cardiologist prescribes and not the shelf oil the patient bought, so that a reader told to stop follows the instruction and asks about a standard softgel if they want one, and a reader with no cardiologist decides by the oily-fish audit for a nutrition claim that is not prevention. For that reader, the nutrition claim's softgel: Futuro Labs Omega 3 Fish Oil, one with food, 180mg EPA and 120mg DHA, 90 for £14.99 at 17p a day.

What to check on the label

Questions people also ask

Is fish oil bad for your heart?

Not bad at a standard dose, and not useful for prevention at any: the outcome trials at a gram a day found no reduction in heart attacks or strokes, and the meta-analyses found a dose-related atrial fibrillation risk most evident at four grams and small or absent below one, so a cardiologist sees no benefit and a small risk at high doses and says stop.

Why did my cardiologist tell me to stop omega-3 but prescribe a different one?

Because the prescription, purified EPA at four grams a day, reduced cardiovascular events in one large trial in patients with raised triglycerides on a statin, and is a different molecule at a different dose in a specific patient, monitored, while the shelf oil is not that drug and does nothing the trials could measure, so the cardiologist stops one and starts the other.

What does NICE say about fish oil for the heart?

Do not offer omega-3 fatty acid compounds for the prevention of cardiovascular disease, in primary or secondary prevention, and do not advise people to take them for that purpose, a position built on the null outcome trials and shared by the European and American cardiology societies for shelf fish oil.

Can I keep taking a low dose of fish oil if my cardiologist said stop?

Ask: a cardiologist's stop is often aimed at a high dose or at the belief that fish oil prevents heart disease rather than at 300mg with dinner for the register's nutrition claim, so tell them what you want to keep and why and let them decide, since they know your rhythm history and the site does not.

Should a healthy lifter with no heart problems stop fish oil because of this?

No, and they should not take it for the heart in the prevention sense either: a healthy reader with no cardiologist decides by the oily-fish audit for the 250mg nutrition claim about normal heart function, one standard softgel for a low-fish plate and none for oily fish twice a week, without a high dose and without a prevention belief.

Sources

1. The large cardiovascular outcome trials of omega-3: around a gram a day of EPA and DHA in primary-prevention populations produced no meaningful reduction in major cardiovascular events, while four grams of purified EPA in people with raised triglycerides on statins reduced events in one large trial, so the supplement-dose story is maintenance and the treatment-dose story is a prescription. PubMed record
2. Meta-analyses of cardiovascular outcome trials of marine omega-3: a dose-related increase in the risk of atrial fibrillation, most evident at doses of four grams a day and small or absent below one gram, a finding that sets the honest ceiling of high-dose omega-3 for a healthy adult. PubMed record
3. NICE guidance on cardiovascular disease risk assessment and lipid modification: do not offer omega-3 fatty acid compounds for the prevention of cardiovascular disease, in primary or secondary prevention, a position based on the outcome trials at supplement doses, with prescription omega-3 for raised triglycerides a separate specialist decision. https://www.nice.org.uk/guidance/ng238
4. The endurance athlete and atrial fibrillation literature: long-term endurance training is associated with a higher risk of atrial fibrillation in middle-aged men, so a runner with a large training history has a baseline the high-dose omega-3 signal adds to, and keeps to the standard rung without a cardiologist. PubMed record

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