Many of us have heard of fish oil and how it can benefit heart health, and as a cardiologist, I get asked a lot of questions about it. The truth is, studies vary on this supplement. Here is information from recent studies that provide insights into the benefits of fish oil.
It All Starts with Omega-3 Fatty Acids
Omega-3 fatty acids are most abundant in marine animals. A lot of the interest in omega-3 fatty acids and fish oils have come from observations that populations who eat a lot of fish are less likely to develop heart disease. Studies have shown that eating fish once or twice a week is associated with a reduced risk of heart disease. Other animal meats also contain omega-3, but fish, in particular, is a rich source of omega-3 fatty acids.
Research Trials & a Stunning Result
In nutrition and medicine, a lot of findings start with an observation and that’s exactly the way it was with omega-3 fatty acids. The observation being that people who eat more fish tend to live longer and have a lower risk of heart disease.
Out of this came a series of trials to study omega-3 fatty acid supplements because we think these polyunsaturated fatty acids are one of the main reasons fish is such a healthy food to include in our diets. So, the question became, “can we extract that out of the fish and use it as a supplement to try and protect us from heart disease?”
Many of the trials produced some conflicting results about whether these supplements are helpful.
But one trial had stunning results. This trial studied a prescription form of omega-3 fatty acids, called icosapent ethyl; the brand name is Vascepa. This product is highly regulated and highly purified, and the study showed it provided impressive heart protecting benefits.
Breaking Down the Research
The information about fish being a part of a healthy diet that protects us from heart disease has become so much a part of our understanding that omega-3 fatty acid supplementation is still a part of the American Heart Association guidelines to help prevent heart disease. And of course, we always recommend eating fish to protect against heart disease.
But, how effective are fish oil supplements? Three specific trials tested the fish oil supplement hypothesis. These were well-conducted studies published in the New England Journal of Medicine. Let’s break them down.
The VITAL Trial
This study was done using the types of omega-3 fatty acids you’ll find as over-the-counter supplements at the same dose recommended by the American Heart Association, which is one gram per day. These trials looked primarily at prevention for men over 50 or women over 55. Over 25,000 enrollees were followed for five years. Some received omega-3 supplements, and some received a placebo. This study showed no difference in major cardiovascular events (which included heart attacks, strokes and heart disease).
So, there was no benefit that they could document in this huge trial for five years.
The ASCEND Trial
This trial also used over-the-counter supplements but studied people with diabetes who did not have a history of heart disease. Over 15,000 people participated in the trial. They took the same dose of a fish oil supplement, one gram per day, and were followed for seven years. Again, the study did not show a significant reduction in cardiovascular events.
The topline data from these two studies is that over-the-counter fish oil supplements did not seem to protect people from cardiovascular events.
The REDUCE-IT Trial
The results of this study were positive and impressive. This was a highly credible study published in the New England Journal of Medicine. It included over 8,000 patients with established heart disease, or who had diabetes plus additional risk factors. They were followed for five years. These participants were already taking a statin, a cholesterol lowering drug, so they were already getting the standard protective, preventive therapy that we recommend for all patients who’ve had a cardiovascular event.
So, these patients were receiving good care, but they still had high triglycerides, which are associated with heart event risks. Omega-3 fatty acids are particularly good at lowering triglycerides, so the thinking was perhaps those who still had high triglyceride levels despite taking a statin would benefit from this specific form of polyunsaturated fatty acid. A key difference in this study is that patients took a highly purified form of omega-3 fatty acid. It’s called icosapent ethyl; the brand name is Vascepa. This prescription drug had already been approved by the FDA for treatment of patients with severe elevations of triglycerides, one form of circulating fats in the bloodstream. To test the effects of icosapent ethyl (Vascepa) on heart disease, subjects were given four grams a day versus a placebo, and were followed for five years.
The results were something we had never seen before related to benefits. They showed a:
- 25% reduction in the combined end-point of heart attack, stroke, cardiovascular death and some coronary revascularization (i.e., getting a stent)
- 26% reduction in just heart attack, stroke and death
- 20% lower risk of death in people getting this highly purified form of omega-3 fatty acids versus a placebo
Impressive Outcomes for Highly Purified Prescription Supplement
We’ve never seen anything like these results in this area of study. It’s important to emphasize that the positive results of the REDUCE-IT trial came from a very specific form of omega-3 fatty acids in a highly purified prescription drug. This was a powerful study, and I think it will influence behavior and opinions about fish oil supplementation and omega-3 fatty acids. Over-the-counter supplements, which aren’t as highly purified or regulated, did not have the same result.
Ways to Improve Your Heart Health
If you have a history of heart disease of any kind, such as stents, angioplasties, bypass or a coronary event, you might want to discuss this purified form of omega-3 fatty acid, called Vascepa, with your doctor to see if it would be helpful for you.
As far as over-the-counter fish oil supplements, as a physician it’s difficult for me to make a strong argument for it. But if I have patients that feel it is beneficial for them in how they feel, I tell them that as long as it’s not causing you harm, ‘go for it.’ Especially if it’s not unreasonably expensive.
In cardiology and in our culture, we have a long history of trying to find that essential element out of the food and making it into a supplement, thinking that’s going to help our health. And for the most part, when put to a rigorous test, these generally fail to protect us from heart disease.
I would much rather see you eat a healthy, plant-based-leaning diet, with healthy fish and meat incorporated on a regular basis.
Dr. Keith Miller, MD
Dr. Keith Miller, MD, is a cardiologist with Bryan Heart.