If you've been worrying eating fish because of the risk of mercury toxicity from eating too much seafood, I have some good news for you. Luckily, there's a mercury-selenium connection that may wash away your fish-eating fears.
Current U.S. recommendations from the Environmental Protection Agency suggest that women who are trying to conceive, pregnant, or nursing – as well as children – should avoid shark, swordfish, king mackerel, and tilefish which contain high levels of mercury; limit consumption of low mercury fish to 12 ounces per week, and further limit locally caught fish to less than 6 ounces per week just in case it might be high in mercury.
The main study that triggered these recommendations about avoiding mercury in fish followed 1022 children born in the Faroe Islands of Denmark in the late 1980's. The study examined correlations of mercury in umbilical cord blood and test scores of those children at age 7. The study concluded that prenatal exposure to mercury correlated to lower IQ in offspring. (source)
It's important to note that some members of the Faroe Island community ate large amounts of pilot whale, a species which contains extremely high levels of mercury – 25 times the amount commonly found in tuna. (source and source) Turns out that whale also happen to be low in a mineral called selenium. Which brings us to…
The mercury selenium connection
While mercury toxicity is definitely something any human should aim to avoid, newer evidence shows that there is a missing piece to the mercury warnings that makes them much less scary.
Selenium counteracts the effects of mercury by binding to it and making a new substance that then allows mercury to pass out of the body without binding to human tissue and wreaking havoc. Because of the strong affinity that selenium and mercury have for each other, as long as selenium is present in higher quantities than mercury, you are most likely safe to consume fish. (source)
Lucky for fish lovers, many of the fish that are high in mercury are also higher in selenium – with shark and swordfish being the two fish known to be consistently low in selenium.
The moral of the story is that most fish contain more selenium than mercury, so they are unlikely to poison you with mercury.
If you’re still concerned about mercury toxicity, you might consider taking a selenium supplement, especially if you frequently consume swordfish or shark.
With the protection of selenium you can enjoy the culinary delights and nutritional benefits of seafood without a big side of worry.
Woo hoo! I don't know about you, I'm super stoked that I don't have to fret about mercury poisoning from fish.
Who's ready for some sushi?!
also, probiotics can help to detoxify mercury. they do it naturally. it’s a part of their metabolic process.
this is why fermented foods are super important and also why japanese foods makes so much sense. there are ferments + high-mineral seaweeds, both protect against toxicity. donna gates talks about this on her body ecology website.
selenium is also used to kill the yeast that causes cradle cap (!!)
So… what type of fish is high in selenium and low in mercury and is safest to eat? Thanks! 🙂
Hi Marian, thanks for the question. To my understanding, nearly all fish are fine, except for shark and swordfish which have lower selenium levels.
Thanks! This is very good news. I haven’t been eating fish for years because of mercury. 🙁 And I love fish. I’ll be looking for foods that contain selenium too; any ideea about that? 🙂 And also, I guess farmed fish is still not recommended and wild is best, right? Thanks again! 🙂
Any shellfish included in this research? I LOVE clams, oysters and shrimp but have been avoiding them because of the possible mercury contamination.
Hi Dorothy, thanks for the question. Shellfish are not at risk for mercury contamination unless they are harvested in severely polluted waters. It’s the larger fish that have always been the bigger concern. I hope this puts you mind to rest!
10 foods rich in selenium (includes shellfish! yay):
http://www.fitday.com/fitness-articles/nutrition/vitamins-minerals/10-foods-rich-in-selenium.html
Any idea as to whether or not selenium will help reduce exposure from amalgam fillings?
Selenium helps but most things that help don’t get past the blood brain barrier where mercury loves to hide. Mercury and some others….but esp mercury are insidious heavy metals…they go deep into the bone and into the brain. But most of the damage isn’t from our foods, but thru amalgam fillings and vaccines.
Yup, I am one of those!! I wasn’t til we adopted 3 kiddos so damaged by their shots…and other things. We are slowly but surely removing the mercury from my adopted kiddoes. It takes such a short time to do so much damage…and such a long time to remove it…and hope that most of the damage is repairable…sometimes it isn’t.
Thanks for sharing! Another cool thing about selenium: Research suggests that methylmercury (MeHg) exposure indirectly leads to heart disease by inhibiting an enzyme that breaks down toxic fats. Selenium somehow offsets the effect that MeHg has on this enzyme, allowing it to have at those fats.
http://www.ncbi.nlm.nih.gov/pubmed/21543280
If you happen to come across any evidence-based literature that provides information on safe levels of selenium intake in regards to mercury exposure, I’d love hearing about it.
what about tuna? im pregnant and have been limiting my consumption of tuna, where does it fall on the list in regards to its selenium content? should I still be eating it no more than once a week?
Hi Carmen, thanks for the question. Shark and swordfish are the only ones with truly low selenium levels. All other fish are fine.
Hi Carmen,
I recently found this great brochure from wpcouncil.org:
http://issuu.com/wpcouncil/docs/education_poster_selenium_mercury/1?e=7174896/2316669
In this poster, both albacore and yellowfin are listed and both have higher selenium levels than mercury 🙂
So would this also help to detox after vaccines containing mercury? And what about Aluminium, which is now a far bigger issue?