Few supplements generate more confusion than fish oil. For years it was recommended almost universally for heart health; more recently, headlines have warned that it might do nothing — or even cause a heart-rhythm problem. As an electrophysiologist who cares about getting this right, let me offer a more honest, more useful picture than either extreme.
Start with the strongest, least controversial point: eating fish is good for your heart. Populations that regularly eat oily fish — salmon, sardines, mackerel — tend to have better cardiovascular outcomes, and oily fish is a cornerstone of the anti-inflammatory, Mediterranean-style pattern I recommend. Omega-3 fats from food are also well established to lower triglycerides. That part isn’t in dispute.
The confusion comes from the supplement trials, and this is where nuance matters. Some large studies of high-dose, purified prescription omega-3 reported more atrial fibrillation — but it’s a mistake to translate that into “fish oil causes AFib.” Those trials used isolated, concentrated preparations at doses far beyond what you’d get from food (REDUCE-IT, for instance, used purified EPA, not fish oil as it exists in the sea). Whether that signal reflects the sheer dose, the stripping-away of the natural cofactors and antioxidants — like astaxanthin — that keep whole fish oil from oxidizing, or oxidized product itself, is genuinely unsettled. Oxidized fish oil, in fact, is a real and under-appreciated problem in the retail market; a rancid capsule is not doing what you hoped.
So here’s my practical guidance. Get your omega-3s from fish on the plate first — that’s the form with the strongest evidence and the least baggage. If you choose to supplement, favor a high-quality, oxidation-protected, full-spectrum product rather than a mega-dose of a single isolated fraction, and clear higher doses with your physician, especially if you have a history of atrial fibrillation. Fish oil isn’t a miracle and it isn’t a menace. Like most things in cardiology, the truth is in the details — and in choosing the whole-food version of nature’s design over an over-processed imitation of it.
This article is for general education and is not medical advice. Discuss supplements and any heart-rhythm history with a qualified physician.
About the author
Andrew Rudin, MD is a cardiologist and board-certified cardiac electrophysiologist with more than 20 years of experience. He works as a consultant helping patients take a natural, root-cause approach to heart health — through diet, lifestyle, and supplements — and sees patients via telehealth through Natural Heart Doctor. His expert commentary has been featured in Medscape and Men’s Journal. Learn more at andrewrudin.com. Work with Dr. Rudin at Natural Heart Doctor →