University of Sask. study finds no mercury damage from high-fish diet
A Saskatoon researcher has shone a bit more light on how an "enigmatic" element affects people who consume it through fish.
"Mercury is a fascinating element, I've been interested in it for more than 20 years now. Its chemistry is fascinating," said Graham George, professor and Canada Research Chair in X-ray Absorption Spectroscopy at the University of Saskatchewan.
He says clarity on the consequences of ingesting low levels of mercury from fish is an important issue for global food security, as many people worldwide rely on fish for protein. The concern over the safety of eating fish stems from the United States Environmental Protection Agency's "conservative" recommendation to avoid some species due to them containing mercury, he said.
However, the type of mercury in question is important, he said.
"So it doesn't matter what element you were you're dealing with, whether it's something that's nutritionally essential in your diet, the chemical form in which that element is presented to you in your diet, or however you ingest it, will control whether it's benign, or beneficial or harmful," he said.
Dimethyl mercury, for example, a colourless, clear liquid, is a "death sentence" if it burns through your skin into your body. But mercury sulphide, used in silver tooth fillings, isn't toxic at all, he said.
His team used the Stanford Synchrotron Radiation Lightsource in California and the Advanced Photon Source at the Argonne National Lab in Illinois to compare the form of mercury in brain samples from two people from the Republic of Seychelles who had consumed bout 12 fish meals a week over their lifetimes and samples from two people who died after accidental mercury poisoning.
The form of mercury in the brains of the people who ate fish was the same as the form found in the fish themselves — and those people showed no neuropathological consequences or neurological deficits that could be linked to mercury exposure.
"There was nothing that could be identified as something that was a health consequence of consuming all that fish and all that mercury over an entire lifetime," George said.
However, the brains of subjects poisoned with organic mercury contained mixtures of mercury compounds, including significantly elevated levels of mercury selenide.
"So the outcomes, the molecular level outcomes, were entirely different," George said.
He cautions that he's not a physician and isn't telling anyone to ignore health guidelines or how much mercury they should consume.
"What I can say is that it's not simple. I don't think you're going to find much fish for sale in the supermarket in most parts of Canada that contains very high levels of mercury."
Personally, he would avoid swordfish and shark, both because some species are endangered and because as predators they accumulate concentrated levels of mercury.
The FDA recommends avoiding shark and swordfish as well due to mercury concerns, in addition to king mackerel, marlin, orange roughy, tilefish and bigeye tuna.
CTVNews.ca Top Stories
Ottawa public school board, 3 Toronto-area school boards launch lawsuit against social media giants
The Ottawa-Carleton District School Board and three school boards in the Toronto-area have launched legal action against social media giants, accusing them of "disrupting students' fundamental right to education."
Several flight attendants from Pakistan have gone missing after landing in Canada
Multiple flight attendants from Pakistan International Airlines have abandoned their jobs and are believed to have sought asylum in Canada in the past year and a half, a spokesperson for the government-owned airline says.
Tipping is off the table at this Toronto restaurant
A Toronto restaurant introduced a surprising new rule that reduced the cost of a meal and raised the salaries of staff.
Rainfall warnings of up to 90 mm among weather alerts in effect for 7 provinces
Rainfall warnings of up to 90 millimetres, air quality advisories and other alerts have been issued for seven Canadian provinces, according to the latest forecasts.
King Charles calls for acts of friendship in first public remarks since Kate's cancer diagnosis
King Charles III gave public remarks for Maundy Thursday, addressing the importance of acts of friendship, following his and Catherine, Princess of Wales’ cancer diagnoses.
A Nigerian woman reviewed some tomato puree online. Now she faces jail
A Nigerian woman who wrote an online review of a can of tomato puree is facing imprisonment after its manufacturer accused her of making a “malicious allegation” that damaged its business.
Donald Trump assails judge and his daughter after gag order in N.Y. hush-money criminal case
Donald Trump lashed out Wednesday at the New York judge who put him under a gag order that bars him from commenting publicly about witnesses, prosecutors, court staff and jurors in his upcoming hush-money criminal trial.
A fight to protect the dignity of Michelangelo's David raises questions about freedom of expression
Michelangelo's David has been a towering figure in Italian culture since its completion in 1504. But in the current era of the quick buck, curators worry the marble statue's religious and political significance is being diminished.
Democrat who ran on abortion rights flips seat in deeply conservative Alabama
Marilyn Lands, who campaigned on abortion rights in deeply conservative Alabama, won a special election to the Alabama Legislature, in a victory that Democrats say illustrates voter backlash to extreme reproductive restrictions imposed by Republicans.