I have written several articles about fish oil supplements, but none has generated the response that I received after my most recent piece, published in The Inquirer in late May. I evaluated a study that questioned the evidence for taking fish oil to prevent heart disease and concluded that I would no longer be recommending it to my patients. I clearly hit a nerve, especially in the pro-supplement crowd.

One reader said the column “is a scientific travesty and medically irresponsible, given the proven science behind high-strength icosapent ethyl (Vascepa) in reducing cardiac risk. At times, Dr. Becker wants to negligently conflate high-dose prescription icosapent ethyl (EPA) with all the fish oil supplements that can be bought off the shelf, which may be pretty much worthless.”

Another reader sent me an explanation by Deepak Bhatt (the primary author of the Vascepa trial) showing a 25% risk reduction in heart attacks and said, “I was a little surprised to see you’ve joined the attack on Amarin’s Vascepa by short sellers in the stock market and others trying to derail the outcome of a $600 million study of 8,000 people performed over seven years under the close watch of the FDA, which approved the use of mineral oil as the placebo.”

» READ MORE: Cardiologist follows the science to a new conclusion on fish oil supplements l Expert Opinion

It is hard to know whether these responses are motivated by an understanding of the science or the financial markets. Vascepa is big business, and its success is largely dependent on the differentiation between it and other fish oils. There seem to be conflict of interests everywhere. The STRENGTH study, showing no cardiovascular benefit of fish oil, was run by cardiologist Steven Nissan. He often speaks about the dangers of conflicts but has received grants from multiple industry sources, including the manufacturer of the main Vascepa competitor. Bhatt, the principal investigator of the REDUCE-IT trial, has received grants from Amarin, the main sponsor.

The article that I wrote (I have no financial backing to disclose) raised many other questions from readers, not all of which were negative. Among them:

  1. “I was wondering if any of the studies took into the account the ick burp taste” of fish oil. The answer is yes, especially the purified prescription versions. If you do have this symptom, you can try keeping your fish oil in the refrigerator, as this will help prevent the “burp” taste.

  2. “Wouldn’t seeds and nuts be a more optimal choice?” Yes, nuts, seeds and olive oil have all been shown to decrease cardiac risk with moderate consumption. Fish, especially the more oily fishes, such as salmon, has also been shown to promote cardiac health. Eating fish with high levels of omega 3 fatty acids two or three times a week is good for you.

  3. “Absolutely beautiful clear-eyed analysis of the fish oil conundrum. Great contribution to soothe the confusion”

  4. “I take one teaspoon of cod liver oil daily and am wondering if this is chemically the same as fish oil.” It is not. Cod liver oil contains large amounts of Vitamins A and D, which at high levels may be toxic.

  5. “I am still wondering if the intake of omega 3 through algae and not fish oil will lead to the same results?” The beneficial effects (which are controversial) are probably from EPA and DHA, which primarily come from fish sources, and not algae.

  6. “One study and it’s over for you? … What if the study had faults?” I share this frustration. It can seem that medicine flip-flops with every new study. In this case, it is the increased risk of developing atrial fibrillation with high doses of omega 3 fatty acids that led to my conclusion that most people should not be taking fish oil supplements.

  7. “How can fish oil, especially from cold water (Alaska, Canada) be harmful or nonproductive to your health?” High-dose fish oil (2 grams twice a day) may cause a higher risk of atrial fibrillation. There is no way to eat that much fish at one sitting.

  8. “I often feel chest pains, palpitations and tiredness and fear that it may be a heart issue.” I wrote back right away to this man suggesting he see a doctor ASAP. The time to make a lifestyle change or consider a supplement is not when you are having symptoms suggesting heart disease.

  9. “Fish oil can still be useful in Ob-Gyn. Please avoid media sensationalism and black-and-white thinking in considering this study.” The studies that I have discussed relate only to the lack of cardiac benefits and should not be generalized to other possible benefits/harms of fish oil.

  10. “What do you recommend?” I am concerned about the cardiac risk of taking high doses of fish oil (4 grams a day}. I think it is interesting that I received very few comments about this risk. Unless you have high triglycerides and heart disease, the data suggest that the dose should be decreased to lower the risk of developing atrial fibrillation. There is no evidence that 1 gram a day causes afib, and that is what I have suggested to my patients if they wish to continue taking fish oil. Rather than supplementing, a better approach may be a diet rich in omega 3s, daily exercise, decreased intake of sugars and junk carbohydrates, not smoking, weight loss, and practicing relaxation techniques.

David Becker is a board-certified cardiologist with Chestnut Hill Temple Cardiology in Flourtown. He has been in practice for more than 30 years.