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Fish oil after a heart attack: TIME misses the mark by leaving out harms, study limitations


3 Star


Fish Oil Has Benefits After a Heart Attack: Study

Our Review Summary

Fish oil capsules in handIn a randomized controlled trial studying fish oil versus placebo, a very modest improvement in heart health markers was observed in people prescribed fish oil. This TIME article demonstrates a good understanding of the study’s novelty, which appears to be among the first to look at potential benefits of fish oil in patients who have just had a heart attack.

However, the story missed the mark in several ways: It didn’t mention the potential harms of taking fish oil if you’re a post-heart attack patient, nor did it discuss costs of the intervention. The only person quoted is the lead researcher of the study–an independent source was needed. Lastly, several limitations of the study are not discussed, including that many patients did not return for post-treatment follow-up.


Why This Matters

Fish oil is a widely used health supplement. Notwithstanding dozens of rigorous studies that cast doubt on its actual health benefits, the popularity of fish oil supplements remains unabated. Most studies have looked at the preventive benefits of fish oil in high-risk populations. The study reported here, on the other hand, examines the protective benefits of fish oil in patients right after a heart attack.

The results suggest that high doses of fish oil after a heart attack may have modest benefits, based on measurements of things like scarring and heart function, which are surrogate markers. News coverage ideally points out this fact–that these markers can’t tell us if fish oil actually reduces the risk of a repeat heart attack, death or other cardiac event.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

Costs of the intervention are not disclosed. A casual reading of the news article may lead one to believe that over-the-counter fish oil was used in the treatment arm of the study. However, our own careful reading of the original study reveals that GlaxoSmithKline (Research Triangle Park, NC) provided both the fish oil and placebo pills. (The study was solely funded by the National Institutes of Health.)

A curious reader might ask what is the cost discrepancy between the fish oil by GlaxoSmithKline and a standard over-the-counter fish oil product, too.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?


The story includes the most salient quantitative evidence of the study:

  • the treatment arm receiving fish oil experienced 6% less scarring than the control arm
  • within the treatment group, people with the highest absorption rate of the fish oil pill showed 13% less scarring than those with the lowest absorption rates

This is sufficient for a Satisfactory rating. However, more context would have made the story stronger: That researchers don’t know what “6% less scarring” means in terms of actually reducing a repeat heart attack, death or another cardiac event.

And from the original study, we learn that compared to standard post-heart attack medical therapies, the benefits of fish oil were not significant:

“after adjusting for standard post-MI (heart attack) medical therapies, there was only a nonstatistically significant trend for the treatment effect of O-3FA (omega-3 fatty acids) on noninfarct myocardial fibrosis (abnormal scarring of the heart muscle).”

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

Harms should have been included.

As made clear in a New York Times story, Dr. James Stein of the preventive cardiology department at the University of Wisconsin Hospital and Clinics explained that “fish oil can be hazardous when combined with aspirin or other blood thinners.” This seems particularly pertinent here as post heart-attack patients are often recommended to take aspirin.

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

The article provides an accurate description of the study design, including the sample size and type of design.

There is, however, a lack of discussion around study limitations. And the limitations were significant enough that we feel they should have been included in any news coverage. For example, readers should be strongly reminded that the study was measuring surrogate markers, and not direct events like repeat heart attacks.

And importantly, the study notes that “a substantial proportion of patients could not return for the post-treatment follow-up visit” and that “no specific recommendations were given with regard to dietary omega-3 fatty acid intake.”

Does the story commit disease-mongering?


There is no disease-mongering.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

Only the lead investigator, Dr. Raymond Kwong, was interviewed.

Does the story compare the new approach with existing alternatives?

Not Satisfactory

No alternatives to fish oil were discussed.

Does the story establish the availability of the treatment/test/product/procedure?


Most people understand that fish oil is available over the counter, so we’ll rate this Satisfactory–though just marginally, because the fish oil prescribed to people in the treatment arm of the study was not standard over-the-counter fish oil pills; see our discussion on this in the “Discuss costs” section above.

Does the story establish the true novelty of the approach?


The article demonstrates a good understanding that the novelty of the study lies in examining the protective benefits of fish oil right after a heart attack. That is, the study is novel in its patient population.

A further discussion of using MRI to assess heart conditions would’ve further highlighted the novelty of the study.

Does the story appear to rely solely or largely on a news release?


The article does not appear to be based on a news release.

Total Score: 5 of 10 Satisfactory

Comments (2)

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Adam Ismail

August 5, 2016 at 10:19 am

Typically the reviews of media articles on this site are high quality and science-based, but the section on the harms of fish oil interventions in this review is decidedly not based in science. There is a myth in the medical community that fish oil has dangerous interactions with drugs like aspirin or warfarin, but it is not supported by any evidence. No clinical study has ever found an interaction between these drugs and fish oils, and this has been extensively reviewed. In fact, in nearly all large clinical trials in secondary CVD prevention, the vast majority of patients have been placed on aspirin or other anti-coagulants, but NONE have ever found an interaction between fish oil and aspirin or any increased risk of bleeding over the placebo. Your review cited a statement by a physician in a NY Times article, rather than the adverse events in the underlying paper. In fact, in the underlying study 98% of the participants were on anticoagulant medications and NO patients experienced either bleeding or a drop in hematocrit in either group. This is an open-access paper and easily verifiable, so it is disappointing that you would instead point to an unreferenced statement in the New York Times rather than either peer-reviewed literature or the underlying study itself to assess the reporting on this paper. Here is a link to the most thorough and recent review of the evidence available on the risk of fish oil and bleeding, alone and in combination with other therapies:


    Joy Victory

    August 5, 2016 at 12:02 pm

    Thanks for your input, Adam. The FDA lists prolonged bleeding time as a potential drug interaction on prescription fish oil capsules. While there may be competing opinions, we think this is a sufficiently evidence-based authority to back up our concern that no potential harms were mentioned.