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A world-leading team of Canadian scientists thinks that diet may play a critical role in limiting the body's absorption of the toxic heavy metal mercury, and they're lining up to test the idea on themselves.
The scientists from the NSERC-funded Collaborative Mercury Research Network (COMERN) have identified dramatic differences in the extent to which mercury from eating fish is absorbed by people in a variety of small Canadian communities.
Since 2000, COMERN researchers have been working closely with communities in the Lac St-Pierre (on the shore of the St. Lawrence east of Montreal) and Abititi regions of Quebec, island communities in the Bay of Fundy, and Innu communities in Labrador, examining their exposure to mercury through the fish they eat.
The research has revealed a mysterious anomaly. Hair or blood samples of individuals in the communities with the highest mercury exposure actually revealed the lowest body mercury levels.
"There's a huge discrepancy between mercury exposure and the extent to which it's absorbed by people in these various communities," says Dr. Marc Lucotte, a biologist at the Université du Québec à Montréal and the lead researcher in COMERN.
What's responsible for this significant difference in uptake?
"We suspect there is something different in the food in some communities and that this is preventing individuals from absorbing mercury," says Dr. Lucotte.
That something, the researchers suspect, could be simply old fashioned tea. Tea-drinking Japanese communities known to be exposed to high levels of mercury through fish consumption have also shown unusually low levels of absorption. Tea is known to be a strong chelating agent – it contains particles called flavonoids which bind with heavy metals to prevent their absorption by the body.
To test this tea theory the researchers are rolling out the dinner plates and rolling up their sleeves.
At COMERN's annual general meeting next week in Gimli, Manitoba, 60 mercury researchers will participate in a unique experiment.
For three days, half the experimental group will eat two meals a day of local Lake Winnipeg fish washed down with six cups of black tea. The other half will eat the fish but drink no tea. Participants will provide blood samples for mercury level testing at the beginning and end of the conference. (Dr. Lucotte stresses that the Lake Winnipeg fish were chosen for the experiment only because COMERN encourages the eating of local foods and that these fish contain only average amounts of mercury.)
Along with the important scientific evidence the experiment could reveal, Dr. Lucotte says that the Gimli tea-and-fish experiment is a crucial part of grounding the researchers in the type of participatory, community-based research they're conducting.
"Being guinea pigs like this takes us back to our roots," says Dr. Lucotte. "It's important for us to remember that we're not just working on a hypothetical story, we're working with real people and real passions. And that we ourselves can be exposed to mercury in our diets and must make choices about this."
He expects the results of the Gimli experiment to be available by January, 2005.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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