Following the publication of a study by Chen et al. titled “Regular use of fish oil supplements and course of cardiovascular diseases: prospective cohort study” in BMJ, mainstream media headlines such as Why Fish Oil Supplements Can Be Dangerous for the Heart and Fish oil supplements may actually pose a risk to your heart sounded an alarm.

Leading groups in the natural products industry have responded to set the record straight on the safety of fish oil. The Fatty Acid Research Institute (FARI) explained that the study looked at incident cases of atrial fibrillation, major adverse cardiovascular events, and death, which were identified through hospital records and death registries. The goal of the study, FARI said, was to determine the role of fish oil supplements in different progressive stages of cardiovascular diseases (CVD), from healthy status (primary stage) to atrial fibrillation (secondary stage), major adverse cardiovascular events (tertiary stage), and death (end stage).

The researchers evaluated 415,737 people ages 40-69 years old who were free of cardiovascular disease at the start of the study. Their conclusion: "Regular use of fish oil supplements might be a risk factor for atrial fibrillation and stroke among the general population but could be beneficial for progression of cardiovascular disease from atrial fibrillation to major adverse cardiovascular events, and from atrial fibrillation to death. Further studies are needed to determine the precise mechanisms for the development and prognosis of cardiovascular disease events with regular use of fish oil supplements.”

Fish Oil Study Conflicts with Majority of Prior Research, says FARI

“Headlines around the world are blaring, ‘Fish oil supplements cause heart disease!’ which is a serious misrepresentation of, not only this specific study, but of the field at large,” said William S. Harris, PhD, President, FARI.

The Natural Products Association (NPA) noted: “A recent study on fish oil use received clickbait attention in the media as ‘increasing risk of cardiovascular disease.’ A more responsible representation would be that ‘self-reported users of fish-oil supplements, exhibited, in one statistical prospective model based on weak correlations a potential for risk.’ 

FARI and NPA both said the study has significant limitations. NPA pointed out that study confounders like family history and lifestyle was not controlled for, nor were brands, formulation or daily dosage amount. FARI shared the following list of specific points of contention with this study:

  • "This study is in stark contrast to the body of evidence that currently exists on fish oil use showing risk reductions for heart issues — specifically atrial fibrillation, stroke, death from CVD, etc.
  • Of the six “significant” associations with fish oil supplement (FOS) use identified in the BMJ paper, five were favorably associated with FOS use and one was not. The latter is what has recently made headlines.
  • Chen et al. failed to discuss any of the previous 16 studies from the UKBB that linked fish oil use with positive outcomes, including the most relevant one by Li et al. which also focused on CVD outcomes. In Li et al., every CVD outcome (except death from stroke), including total mortality, was statistically significantly and beneficially associated with FOS use. The findings by Li et al. were from the same cohort as Chen et al. using the same exposure (FOS use or not)—also published in BMJ—and yet Chen et al. said nothing about why their results directly contradicted those of Li et al.
  • Finally, self-reported FOS use is a far less objective measure of omega-3 intake and status than is actual blood levels of omega-3 fatty acids. A recent report from O’Keefe et al. in the UKBB (published in the journal Stroke) looked at the association between plasma omega-3 levels (particularly DHA) and risk for death from all causes and from CVD, cancer and remaining other causes. They found significant inverse (beneficial) associations between DHA levels and risk for all four mortality outcomes. Why did this report receive virtually no attention by either Chen et al. or the press?"

The reality: EPA and DHA have qualified health claims

Daniel Fabricant Ph.D., NPA CEO and President, said, “Unfortunately this study is being held out as definitive and eye-raising by the media when the study’s authors state the shortcomings plainly within the study 'as an observational study, no causal relations can be drawn from our findings' and '(the) study did not consider behavioural changes in populations with different cardiovascular profiles because of limited information, and variations in outcomes for different cardiovascular states merits further exploration.' The reality is that since 2004 FDA has allowed a qualified health claim supporting that consumption of eicosapentaenoic acid (EPA) and docosahexaenoic (DHA) omega-3 fatty acids may reduce the risk of coronary heart disease, 20 years later that’s still a sound rule of thumb and as always consult your health care provider.”

In addition to the 2004 claim, NPA pointed out that in 2019 FDA approved another qualified health claim for fish oil stating that consuming EPA and DHA in food or dietary supplements may reduce the risk of hypertension and coronary heart disease. "Under FDA’s health claim regulations," NPA explained, "foods and dietary supplements that bear a health claim must meet requirements regarding levels of certain nutrients. One of these enforcement discretion factors is that dietary supplements and conventional foods labeled with the qualified health claim contain at least 0.8 g EPA and DHA (combined total) per serving.”

Concerns over consumer confusion

Speaking to the damage the headlines surrounding the Chen et al. study may have caused, FARI’s Dr. Harris noted: “This new BMJ study seemingly takes omega-3 research a step back, especially given the sensational headlines it has generated. The mainstream press conclusions from this study are simply overblown, disappointing and reckless. Fish oil isn’t the danger. These headlines are.” He added that the study will likely cause confusion for those who consider fish oil supplements important to their heart health, and noted that it will be important to make sure consumers understand the full context of the pros and cons of fish oil use before they stop taking their supplements.

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