This just in from The Miami Herald: “Most adults need not worry” about risks associated with tiny traces of methylmercury in seafood. And researchers from the University of North Dakota announced that, thanks to a nutrient called selenium, mercury levels in fish are “not as harmful as previously thought.” Hooray! Now, let’s file all of this news away under “we told you so.”
As scientists from Harvard University and the Food and Drug Administration have been saying, the nutritional benefits of omega-3 fatty acids in fish – including healthy hearts and smarter babies – far outweigh the hypothetical risks associated with mercury. The levels of naturally-occurring methylmercury in ocean-caught fish are so tiny that you could probably eat a hundred cans of canned chunk light tuna every week for a lifetime without getting mercury poisoning. (Click here to find out for sure.)
The reason why, as scientists from the Energy & Environmental Research Center at the University of North Dakota are explaining this week, has a lot to do with selenium:

"Selenium is an essential nutrient in healthy brain development and protects the brain from oxidative damage," said Dr. Nick Ralston, an EERC Research Scientist involved with the studies. .. “The more selenium in the tissue, the less mercury toxicity occurs. Since fish in some areas have much higher levels of selenium than mercury, the consumer receives the healthy benefits of selenium and a natural defense against mercury."

In other words, as we put it in the title of a 2006 report, selenium is “The Flip Side of Mercury.” But overblown mercury warnings, along with a lack of public understanding about the protective effects of selenium, has had negative public health consequences since so many consumers have over-reacted by steering clear of the canned tuna aisle.
The verdict is in – again: Selenium, protein, and omega-3s in fish are your friend. Too bad we can’t say the same about seafood scaremongers.