One of my roles as a naturopath has become helping my patients make sense of contradictory online nutritional recommendations. The latest headlines to confound are about fish oil.
On November 10th, two heart health / fish oil studies were released. Both are out of Harvard, and were presented at the American Heart Association’s Scientific Sessions held in Chicago. The following week, media coverage was baffling to anyone trying to decide what supplements to take. There were headlines like November 11th’s Toronto Star article: Fish Oil Drugs Protect Heart Health, Two Studies Say. But also this one from Jezebel, Fish Oil Might Be a Lie, According to Science. Or “Fish Oil Doesn’t Really Do Anything, Study Suggests from zmescience. Also, Vox’s Do Fish Oil Supplements Work? Science Gives us Slippery Answers. All of these articles cited one or both of the same two studies.
This. Is. Confusing. The journalists’ interpretations all sound plausible and the sources run from moderately to highly reliable. In order to understand the recommendations myself, I thought a closer look at the two studies might be useful.
The first study is the Vitamin D and Omega-3 Trial (VITAL). The randomized, placebo-controlled trial included 25,876 men aged 50 years and older and 13.085 women aged 55 years and older. The participants were followed for an average of 5.3 years.The study looked at both Vitamin D and Omega-3, and their impact on cardiovascular events and cancer rates (to keep it simple, I will just look at the fish oil / heart health link). The fish oil intervention was 1 gram per day of Omacar which includes 460 mgs of eicosapentaenoic acid (EPA) and 380 mg of docosahexaenoic acid (DHA), the active ingredients.
According to the researchers, there was a reduction in major cardiovascular events (mainly heart attack and stroke) among the participants receiving omega-3 fatty acids over those receiving placebo, but the reduction was only 8% – not statistically significant. However, the results tell a different story when you separate out stroke from heart attack. The omega-3 fatty acid intervention lowered the risk of heart attacks by 28% and the risk of fatal heart attack by 50% – both significant findings – but had no benefit on stroke (or cardiovascular deaths not related to heart disease).
Additional interesting findings were among 2 subgroups. For those who reported low fish intake at baseline (less than 1.5 servings per week, where one serving is 4-5 ounces) fish oil supplementation provided a 19% reduction in major cardiovascular events, including a 40% reduction in heart attacks. And in African Americans, omega-3 supplementation led to a 77% reduction in heart attacks. The researchers state that both of these findings deserve follow-up studies.
The second study was also a randomized, placebo-controlled trial. The REDUCE-IT study involved 8179 patients with an elevated cardiovascular risk from 11 countries. All participants were taking a statin (cholesterol-lowering medication) prior to and throughout the study. Average follow-up time was 4.9 years. In this study, the fish oil intervention was 4 grams of pure EPA (Vascepa brand) per day.
The results of this study appear unequivocally positive. They found a 25% relative risk reduction of a major adverse cardiovascular event (death, heart attack, stroke, unstable angina requiring hospitalization, etc.) in the fish oil group, over placebo, deemed “highly significant”. The benefit is equivalent to that seen by one of the most popular statin drugs, atorvostatin. The EPA is thought to work by lowering triglycerides in the blood. All study subjects had elevated triglycerides at the start of the trial.
What to Think?
Taken together, the studies seem to point to an overall benefit to fish oil for improving your cardiovascular risk factors. In the REDUCE-IT study, the benefits were clear: taking high dose EPA (4g per day) will help prevent heart attack or stroke. In the VITAL study, the benefits were less clear, but the fish oil dose was also far less (1 gram of combined EPA/DHA). I wonder if the results in that study would have been stronger, if they had used a higher dose.
I’m not sure why the media coverage of these studies has been so inconsistent. The writers may be allowing a pre-existing bias to interfere with their objective coverage (eg. “I think supplement companies are just trying to rip you off”). Or there is the “click bait” effect – media outlets choosing headlines and perspectives that are controversial in order to increase their readership. The more readers who come to their website, the more advertising revenue they can generate.
But, as a naturopath, I find this disturbing. Consumers of media are just trying to make the right choice for their health. If they get mislead and decide to stop taking their fish oil based on false information, it could increase their risk for heart attack, or possibly death. I don’t think it’s too much to expect those who cover health news to keep the readers’ well-being in mind and stick to the facts.
If you have any questions about recent health headlines, please talk to your naturopath or other qualified healthcare practitioner before making any big decisions.