Fish Oil in the News Again: But Is It Snake Oil?

CC BY 2.0. Zeyus Media

New study on fish oil benefits has some foibles, the least of which is it's not fish oil.

Headlines declaring the benefits of fish oil once again appear poised to pump up the demand for omega-3 supplements. Given that depleting the ocean of fish in order to squeeze out the good stuff and put it in a pill seems like a trend a TreeHugger should question, we looked into the science behind the headlines and found more than just sustainability questions.

It's not fish oil

The current headlines communicate results from a clinical study called REDUCE-IT announced November 10 at the American Heart Association’s annual scientific sessions in Chicago and published in the New England Journal of Medicine.Responsible news organizations take care to refer to the drug tested as "fish-oil derived" or at least as a "fish-oil drug" but the many purveyors of fish oil supplements will certainly use the fanfare to boost the image of their products by association.

In fact, the study did not test "fish oil" supplements, but a drug called Vascepa, which is highly purified icosapent ethyl (also known as ethyl-eicosapentaenoic acid). Eicosapentaenoic acid, EPA for short, is one of the types of omega-3 fatty acids found in fish oil. Omega-3 fatty acids are important to the diets of humans, and all mammals, because we cannot make it ourselves. The term "omega-3" refers to the fact that the first chemical double bond is 3 links in from the end of the molecule. (A double bond is known to chemists as an "unsaturation," which is the reason we use the terms saturated and unsaturated fats.)

The study of this single-molecule drug may not be representative of the health effects of fish oil in general. In particular, the supply of a highly purified omega-3 fish-oil component could solve some issues such as the potential for fish oils to carry contaminants like PCBs which bioaccumulate in the fats of marine creatures.

Did the placebo make people sick?

The biggest foible in the study is not the fish-oil nor the fish-oil derived drug. It is the placebo.

The scientific chat rooms on this study are full of voices concerned that mineral oil used in the placebo pills to give them the glow people associate with fish oil supplements might have actually caused negative health effects in the control population. Mineral oil can reduce the effectiveness of statin drugs that patients in this study were using to control their cholesterol levels. If that is the case, the margin of protection suggested might be falsely elevated.

Some medical professionals believe that even if the placebo had some effect, it would not be enough to account for the 25% reduced risk of heart attack or stroke found. Cardiologist Carl Orringer of the University of Miami Miller School of Medicine (and who was not involved in this study) notes, “Even if there was a slight effect of mineral oil, it would be so minimal that I don’t believe there is any way that this could account for the striking difference seen.”

Other studies using a corn oil placebo may help to elucidate the truth of the matter.

Will the fish-oil derived drug make people healthier?

Like many studies, this one focuses on a very particular group of patients - people with high triglycerides plus an elevated risk of heart disease or diabetes, who are already on statins, drugs which aim to control bad cholesterol levels.

In short, this means that the drug may be of no benefit to people who are not in this particularly high-risk group. This can help explain why many studies don't confirm the same benefits.

What is the company's game?

The REDUCE-IT clinical trials are paid for by the company, Amarin Pharma Inc., that produces the particular fish-oil-derived pharmaceutical studied.

Funding sources with potential for conflicts of interest have been implicated in a lack of reproducibility of scientific findings. While this by no means discredits any particular study, Amarin has not done themselves any favors in the scientific community by hyping the pending results of the study before the details of the study design and results were available. This leads to people making big claims, spiking a pharma stock, before the truth of the science can be fully understood. It makes the study look more like marketing, and less like an objective effort to find the truth.

So should people take fish oil supplements or not?

If you are worried about heart health, talk to your doctor. He or she will keep tabs on whether a drug is worth it based on each patient's specific conditions.

But if you aim to improve and maintain your general health, trying eating fish instead of fish oil. Or better yet, look to vegetable sources of omega-3 fatty acids, such as flax, chia, hemp, and sesame seeds. And don't overlook the importance of exercise and balance in your diet.

If you simply must hop on the supplement bandwagon, look for one of the many products based on algae or other sources of the oils instead of fish, to keep your sustainability impact low.

The full study is available online:
Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia