This news release summarizes a recent paper published in Mayo Clinic Proceedings that evaluated the effect two types of omega-3 fatty acids — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — had on reducing risk of coronary heart disease. The report was a meta-analysis, meaning researchers evaluated the findings of multiple published studies. Specifically, the meta-analysis looked at 18 randomized controlled trials (RCTs) and 16 prospective cohort studies. RCTs are designed to measure the effect of a specific intervention under clearly-defined, experimental conditions. This means that researchers aim to determine, with some degree of certainty, whether a specific intervention is causing a specific outcome. Prospective cohort studies follow large groups of people over extended periods of time, allowing researchers to determine what characteristics or behaviors may be associated with specific outcomes. Because of the nature of these cohort studies, they can only tell researchers if a behavior or practice is correlated with an outcome — but not whether the behavior is causing the outcome.
These sorts of meta-analyses can be extremely valuable tools for assessing a broad body of work on a given subject. However, this news release is problematic. It is written in a way that is confusing, if not misleading, and fails to make clear that the scientific-sounding organization that funded the study (and wrote the release) is an industry group that was created to promote the global use of omega-3 supplements or foods that are high in omega-3s.
According to the National Heart, Lung and Blood Institute, approximately 370,000 people die of coronary heart disease each year in the United States. Many adults make decisions about their diet, activities and lifestyle based on how those decisions may affect their heart health. Research on subjects such as how omega-3 fatty acids affect heart disease risk play an important role here. According to a 2015 Washington Post article, people in the U.S. spend $1.2 billion each year on fish oil supplements, largely because they contain omega-3s that consumers think will reduce their risk of heart disease. But increasingly consistent evidence shows that fish oil does not, in fact, protect against heart disease. If people are going to make informed decisions about their personal health — and how they spend their money — they need to have good information that they can actually understand. News releases like this one make it hard for most consumers to understand exactly what the research says.
Cost is only addressed in a quote from the executive director of an omega-3 industry organization, who refers to increasing one’s omega-3 intake as an “inexpensive” lifestyle change. What does “inexpensive” mean? What may be cheap for one consumer could be cost-prohibitive for another. What’s more, it’s difficult for any reader to work out what the cost may be, because the release doesn’t make it easy to determine how much of EPA or DHA one needs to take in order to see any potential benefit. It is only in the tenth paragraph, which quotes an editorial suggesting that taking “at least 1 gram of EPA+DHA per day…continues to be a reasonable strategy.” That’s still not necessarily clear for many consumers, since it’s not directly linked to the benefits discussed elsewhere in the release, but it’s the only reference to how much an individual might need to consume — and it’s buried near the bottom of the release.
The release tells readers that, among the RCTs, “there was a statistically significant reduction in [coronary heart disease] risk in higher risk populations, including…16 percent in those with high triglycerides and 14 percent in those with high LDL [low-density lipoprotein] cholesterol.” So the release is claiming that seafood, supplements and pharmaceuticals offer a 16 percent reduction in risk of coronary heart disease for people with high triglycerides. That sounds good, right? But over what time span? A year? A lifetime? And how high does a person’s trigylceride count need to be in order for that person to have “high triglycerides?” The release doesn’t tell us. And then things get really confusing. Consider this statement: “A non-statistically significant 6 percent risk reduction among all populations in RCTs, a finding supported by a statistically significant 18 percent reduced risk of [coronary heart disease] among prospective cohort studies.” Does the statistically significant finding somehow make the non-statistically significant finding more, well, significant? No. Does bundling those two things together into one sentence muddy the waters for readers? You bet. Does the release still fail to explain the time-frame it is using when discussing risk reduction? Yes.
Providing readers with figures describing the absolute risk reduction would have been very helpful here.
The release does not mention any potential problems associated with omega-3s. And there are potential harms. For example, the University of Maryland Medical Center notes that patients should consult with their doctors about potential interactions with prescription drugs before taking omega-3 supplements, and adds that “High doses of omega-3 fatty acids may increase the risk of bleeding, even in people without a history of bleeding disorders, and even in those who are not taking other medications.” There are concerns about other potential harms as well, such as whether fish oil supplements may increase risk for prostate cancer. We don’t expect a news release to include an exhaustive summary of all the possible harms associated with a particular intervention. But we do expect a news release to at least acknowledge that the potential for harms exists, when appropriate.
The release does tell readers the total number of RCTs and cohort studies that the meta-analysis looked at, as well as the overall number of study participants involved. That’s good. The release also articulates the difference between the two types of studies — which is also a good thing. However, things get dicey when the release starts discussing benefits. For example, the release tells readers that “The study reviewed 18 randomized controlled trials (RCTs) and 16 prospective cohort studies, with 93,000 and 732,000 subjects, respectively.” As noted above, the release also states that the study found a “16 percent [risk reduction] in those with high triglycerides and 14 percent in those with high LDL cholesterol.” It would be natural for readers to assume that those risk reduction numbers are based on the 18 RCT studies, which evaluated 93,000 study participants. But that would be wrong. According to the journal article, only six of the RCT studies looked at patients with “high triglycerides,” and only five of the RCT studies looked at patients with high LDL cholesterol. So, while the release is not technically incorrect, it’s misleading — and that’s not okay.
No disease mongering here. But there’s also no context about the prevalence of coronary heart disease.
This is a really close call. The story makes clear that the research was funded by the Global Organization for EPA and DHA Omega-3s (GOED) — which also issued this news release, through AAAS’s EurekAlert! news service. The release also quotes two GOED employees, and clearly identifies them as such. However, the release doesn’t include any language explaining what GOED is, what it does, or who its members are. And that’s important, because GOED is not an independent research organization, it’s an industry group that exists to promote consumer use of products that contain omega-3 fatty acids.
There are many actions that invididuals can take to reduce their risk of coronary heart disease, including losing weight, exercising regularly, and managing stress. The release doesn’t mention any of them. This is particularly problematic given that these are actions which are not mutually exclusive: one could lose weight, exercise regularly, manage stress and eat more fish (for example).
The release refers to consuming EPA and DHA in the form of either seafood or supplements, so we’ll give this a pass. However, that single reference to sources of EPA and DHA is only found in a quote in the tenth paragraph.
There are a ton (to use a technical term) of studies on omega-3 fatty acids and heart disease, including lots (and lots) of meta-analyses (like this one or this one, for example). What sets this meta-analysis apart? The release doesn’t tell us.
As noted above under the Why This Matters section, there’s considerable evidence and recent consensus that fish oil doesn’t have much if any effect on cardiovascular disease.
A few points here. First, the release states that increasing their consumption of omega-3s is a “change that most consumers need to make.” That’s over-reach, and that alone would give the release an unsatisfactory rating here.
But there’s one other note that we’ll make here, since it doesn’t really fit anywhere else: at no point does the news release tell readers what EPA and DHA stand for. Nor does it explain what they are, or even what omega-3 fatty acids are, much less how they may be beneficial for heart health. If you’re going to use terms that are not common knowledge — such as “DHA omega-3s” — please give your readers some idea of what you’re talking about.