The consumption of dark fish, such as salmon, swordfish, bluefish, mackerel, and sardines, may increase one’s risk of atrial fibrillation, an irregular heart beat rhythm associated with stroke, dementia, heart failure, and a shortened lifespan.
Red Fish, White Fish; Dark Fish, Atrial Fibrillation, 5.0 out of 5 based on 2 ratings
Image thanks to Popfossa and marc kjerland.
Another surprising fish story out of Massachusetts last year. Atrial fibrillation… is the most common clinical cardiac arrhythmia, an irregularity of our heart beat rhythm, which can set you up for a stroke, increase your risk of dementia and heart failure, and significantly shorten our lifespan. Previous findings on the effect of diet have been conflicting. Some studies have found alcohol, caffeine and fish consumption to be good in terms of preventing or resolving atrial fibrillation, and other studies have shown them all to be bad.
It’s when this kind of situation arises in nutritional science, you pull out the big guns and put it to the test in one of the bigger better studies, like the famous Framingham Heart Study population like they did here.
They found no effect either way in general from the consumption of alcohol, caffeine, or fish, but when they looked closer they observed an association between the consumption of dark fish and atrial fibrillation. A 6-fold higher hazard ratio. What they’re talking about is basically salmon, swordfish, bluefish, mackerel, and sardines.
The conclude their findings may suggest a “true adverse effect of dark fis and fish oil on certain subtypes of atrial fibrillation, proposing that “potential toxins such as dioxins and methyl mercury accumulated in certain fish may have a negative effect on cardiac arrhythmia.”
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Serena.
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See also Boosting Heart Nerve Control for how one can improve heart rhythm function through diet, and there are other videos on alcohol, caffeine and the persistent organic pollutants that build up in the aquatic food chain. The mercury that accumulates in fish can also affect brain function in children and adults, just one of more than a thousand topics I cover.
Also be sure to check out my associated blog posts, Mercury Testing Recommended Before Pregnancy and Eating To Extend Our Lifespan.


