Do Fish Oil Supplements Live Up to Their Claim?

Podcast Transcript

Announcer:

Welcome to Love Your Heart, brought to you by Cleveland Clinic's Sydell and Arnold Miller Family Heart Vascular and Thoracic Institute. These podcasts will help you learn more about your heart, thoracic and vascular systems, ways to stay healthy, and information about diseases and treatment options. Enjoy.

Steven Nissen, MD:

I'm Dr. Steve Nissen, and I'm the chief academic officer of the Heart, Vascular and Thoracic Institute here at the Cleveland Clinic. I'm here with my colleague, Dr. Luke Laffin, who will also introduce himself.

Luke Laffin, MD:

Great to be with here you here today, Dr. Nissen. I'm Luke Laffin. I'm a preventative cardiologist. I'm co-director of the Center for Blood Pressure Disorders here at the Cleveland Clinic, as well as medical director of Cardiac Rehabilitation.

Steven Nissen, MD:

Okay, we're going to talk about an interesting topic. It's got a long name, n-3 polyunsaturated fatty acids. Dr. Laffin, maybe you can explain what this is.

Luke Laffin, MD:

Essentially, these are Omega-3 fatty acids that have been studied for decades, as alluded to, as a potential benefit for cardiovascular risk reduction. These are found in nature in fish that we eat, but really the studies have looked at supplements and prescription drugs that actually contain Omega-3 fatty acids.

Steven Nissen, MD:

For most people, this is fish oil. You walk in any pharmacy and you can see lots of different brands of fish oil. Let's maybe talk for a moment about the supplements. What are in the supplements? How much fish oil is in there? What do we know about them?

Luke Laffin, MD:

Well, supplements, the typical over the counter supplements that we see for fish oil are a combination of EPA and DHA, which we see. Then, there's prescription supplements as well, which are either a combination, again, of EPA and DHA, or just pure EPA.

Steven Nissen, MD:

Yep. Now, one thing I'd like to comment on is that we do not recommend dietary supplements for most conditions. Many people are taking them. They're not regulated by the FDA, so we don't always know what's in them. Some of them have been tested by consumer organizations, and they can be contaminated with mercury and other things. Supplements are generally not very safe. What are the claims that are made for these supplements, for these fish oil supplements?

Luke Laffin, MD:

Well, it's really interesting, because if you look at the labels, there's some, pardon the pun, fishy language that they use with it, where they'll put a little asterisk by it and say for heart health or cholesterol health. But, when you look in the fine print, they'll say this claim has not been evaluated by the FDA. Okay. But, they can put this on there, just the way that the supplements are regulated. You have to be really careful. A lot of people, as you alluded to, think that supplements are safe. Oh, I can get it over the counter, it should be fine. Not necessarily. Oftentimes we see, at best, nothing's happening and you're just losing money. At worst, they can have negative impacts.

Steven Nissen, MD:

These supplements contain a small amount of EPA and DHA, less than one gram typically. Have these low doses been studied? What do we know about them from the medical literature?

Luke Laffin, MD:

The over the counter have, it's not a lack of data, it's that the data is not convincing. They don't show any difference in cardiovascular risk reduction, when you look generally across these, what we would typically think of as the over-the-counter supplements.

Steven Nissen, MD:

These have been very large studies done by very reputable organizations, and they've had a very large number of participants. We're talking about 10,000-plus people. They just didn't show any benefits. Low dose fish oil that's available over the counter doesn't do very much. But, there are prescription strength fish oils, and they typically contain about four grams of these Omega-3 fatty acids. What do we know about the four gram doses?

Luke Laffin, MD:

Well, we know that there's been a lot more talk about them over, probably about the past four or five years, with the release of some big studies evaluating their benefit in cardiovascular risk reduction, particularly in people that have elevated levels of serum triglycerides, which are a component of lipid in the blood. What they showed was really differing findings.

Steven Nissen, MD:

Let's talk about that a little bit. The trial that's often noted by people is known as REDUCE-IT, and it used a purified form of EPA. What were the claims made from the REDUCE-IT trial?

Luke Laffin, MD:

Well, the top line data, or the primary outcome, suggested that there was a 25% risk reduction, so in terms of decreasing cardiovascular risk by 25% among those individuals that took the icosapent ethyl, which was the pure EPA product, compared with placebo. There's a lot of caveats to that, which we can definitely discuss. But, that was the top line data and that's what circulated in the media a lot.

Steven Nissen, MD:

We were critical of the results, mainly because whenever you do a study like this, you have to have a placebo. Half the patients have to get the drug, half of them get the placebo. The placebo that was used was mineral oil, and recently a study was published showing that mineral oil had very significant adverse effects. If the placebo is doing bad things, it may make the drug look good. There is also a study that we led here at the Cleveland Clinic known as the STRENGTH trial. Very large, more than 10,000 patients. Looked at a four gram dose of a little bit different fish oil, and there was no benefit whatsoever. This is an area of really, really strong controversy. We've taken the position, I certainly have, that the evidence is not very good for the benefits of these prescription fish oils. Other physicians will have different opinions, but we're here to tell you what we really think. I think the evidence is just not there and we need more studies in order to be able to give a strong recommendation to take these products. I'd be very interested in Dr. Laffin's take, whether he agrees or disagrees.

Luke Laffin, MD:

I think my thought process has changed a lot since the initial data from the REDUCE-IT trial came out. Initially, I was actually very hopeful. It's a population that doesn't have a whole lot of great treatment options on top of statins, which the majority of those patients were already taking, and so I did prescribe it early on. But, as you alluded to, this data from STRENGTH and then of course the more recent data showing inflammatory markers were increased with the mineral oil placebo, has led me to pause a number of the prescriptions that I'll write for it. Now, I do have a few patients on it still. I think that the benefit for it outweighs any potential risks, and there are some risks which we can talk about. I use it very sparingly. I'm not going to say never, but I use it very sparingly.

Steven Nissen, MD:

The risks that Dr. Laffin was referring to is all of the studies show an increased risk of atrial fibrillation with these potent fish oils. People need to be aware of that, particularly if they've had a history of atrial fibrillation. That's certainly a reason to be cautious.

Luke Laffin, MD:

Right. There was a signal towards bleeding too, correct?

Steven Nissen, MD:

Yeah. Well, not so much so. I mean, it was a little bit more weaker signal, I would say for sure.

Luke Laffin, MD:

Okay.

Steven Nissen, MD:

Let me leave you with one final thought. It's always the right thing to talk to your doctor about all of this. There are differing opinions. We've given you two opinions. They're slightly different, but they're maybe more aligned. It's a conversation that you should have. If you're not certain, it's always a good idea to get a second opinion. You want to take drugs that have proven benefits. I would strongly urge people not to take fish oil supplements, and to be cautious about the prescription drugs. Thank you, Dr. Laffin, for this very interesting discussion.

Luke Laffin, MD:

Great to speak to you.

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