“Should I take fish oil?” The question came from Karen, a patient of mine, who suffered a heart attack 3 months ago.
Karen is doing very well. She is participating in cardiac rehabilitation, taking her medications and her cholesterol numbers are great, but she wonders if there is anything else she should be doing.
As a cardiologist, my patients ask me frequently about fish oil supplements. And just like Karen, those patients want to do everything they can to keep their heart healthy and have heard that fish oil supplements are good idea.
It’s a simple question, but the answer is anything but simple. Whether fish oil supplements are beneficial or not has become quite controversial in recent years, and for me, like many physicians, the recommendation I give today isn’t the same as the one that I gave 10 years ago.
Are Fish Oil Supplements Good for Your Heart?
The story of fish oil and heart health started with the observation that several populations (like the Inuit in arctic regions) who had a high intake of fatty fish also had low rates of heart attack and stroke. Since these diets are high in polyunsaturated fats, or omega-3 fatty acids, this led to the hypothesis that these fats may be good for heart health.
In the late 1990’s, a large Italian study (called the GISSI study) showed that heart attack survivors randomly assigned to polyunsaturated fatty acids (omega-3 or “fish oil”) supplements had a reduction in death, heart attack, and stroke compared to those who did not take the supplement. This prompted the American Heart Association to recommend fish oil supplements to patients with heart disease, and many cardiologists followed suit. It wasn’t long before the benefits of fish oil were being touted even for people without heart disease.
Fish oil seemed to be a new miracle supplement that just about everyone should be taking.
But like many things, fish oil wasn’t as straightforward as it seemed at first. Several subsequent, more rigorous studies failed to show a heart benefit from fish oil supplements.
What Does the Evidence Say?
Medicine prides itself on being “evidence-based”. In the best of circumstances, this means our recommendations and treatments have been vigorously tested in well-designed scientific studies and have proven and reproducible benefits.
Evidence-based medicine works well when the evidence mostly points to the same conclusion, but what should we do when there are mixed results? When some studies show a benefit, but others do not? Typically, this is a situation where the “truth” depends on your viewpoint. Some will look at the evidence and see a stronger case for benefit. Others will not.
One commonly used strategy to decide a question where several trials have shown mixed results is to combine all of the trials into one study, which is called a meta-analysis. The idea is that by combining the data, we may be able to better decide which is the correct answer.
Should I Take Fish Oil?
Back to my patient’s original question, the answer she gets likely depends on who she asks.
Here is what I tell my patients about fish oil supplements.
1. If there is a benefit to fish oil supplements, it is likely small.
2. A much better way to get omega-3 fatty acids is to eat fatty fish such as sardines, herring, albacore tuna and salmon among others. The American Heart Association recommends fish (particularly fatty fish) at least twice a week.
3. If you do decide to take a fish oil supplement, find a high-quality supplement manufactured from a reputable company.
The bottom line: I don’t recommend fish oil supplements to my patients, and I don’t take them myself. My belief is that we haven’t figured out how to get the magic ingredients of healthy food into a pill yet, but I understand that others will look at the data and come to a different conclusion.