The mercury content varies depending on the type of fish.
August 7, 2020 22h37
Sensor rumors: avoid eating fish because of mercury ?
The fish is among the foods most consumed in the world. And with him, comes back periodically, and fear, that of the mercury contamination. Should you avoid drinking ? The Detector of rumors back on the old concern.
In the 1950s, a mercury contamination in Minamata, a coastal city of Japan, has been identified as the source of important neurological problems in the population, and 14 deaths. The balance sheet, years later, would be an estimated 3000 patients. From the beginning, it was realized that these were mostly families of fishermen : their diet in fish and seafood had so quickly aroused suspicion. We finished by identifying, in 1959, a mercury contamination in fish, caused by the spills, since the 1930s, one of the largest chemical plants in the country.
This disaster has remained long in the collective imagination, ” says Dave St-Amour, a professor at UQAM, who is interested in the effect of environmental contaminants on the brain. The “Minamata disease” has left the impression that the consumption of fish was dangerous. “In Minamata, these concentrations were, however, 1,000 to 10,000 times higher than what we normally measure “, he says.
All fish are not equal
Beyond this disaster, it must be remembered that the mercury content varies depending on the type of fish.
According to the ministry of Agriculture, Fisheries and Food of Quebec (MAPAQ), the maximum concentration of mercury allowed in the edible flesh of the fish sold in grocery is 0.5 mg/kg. All samples of fish available on the market and analyzed by the MAPAQ between 2011 and 2016 have been deemed compliant to this standard. The fish caught in the framework of sport fishing, however, are not subject to any control.
Several species, therefore, have mercury levels higher, recalls in particular the ministry of the Environment and the Fight against climate change. In general, the concentration of mercury in a fish increases as a function of its rank in the food chain. In other words, the predators that eat many other fish contain themselves of mercury, are most at risk. Thus, the ” prey “, such as trout, salmon and cod, are low in mercury, while swordfish, shark, and certain types of tuna, contain more of them. Health Canada recommends not consuming more than 150 grams of these fish per week. Pregnant women and young children should be even more careful.
We should also remember the matter of the forest areas are flooded, for example, following the construction of large dams: there has long observed mercury concentrations higher in the flesh of the fish. This is the case, for example, in Quebec, reservoir Gouin and Baskatong. The concentration is not sufficient for that experts recommend not to consume fish, but rather to limit the consumption.
The benefits outweigh the risks
An international research on the medical records of more than 400,000 people concluded that in 2018 that the consumption of fish reduces significantly the mortality associated with several conditions, including cardiovascular disease and Alzheimer disease. The researchers believe that this reduction in mortality can be explained by the high content of fish in omega-3 fatty acids that are described as beneficial for cardiovascular health, at least in people at high risk.
In a 2010 joint report, the world health Organization and the United Nations Organization for food (FAO) insisted also on the benefits associated with the consumption of fish to combat cardiovascular disease, claiming that the benefits outweigh the risks.