Those who eat too much canned tuna risk mercury poisoning, as it is known in fact this metal accumulates in larger fishDon't store avocado like this: it's dangerous
For many, opening a can of tuna is a practical choice that allows you to stock up on protein at low cost and without having to cook. But what happens to the body if we eat too much canned tuna? There is a side effect to consider, which should push us to limit the consumption of this food to a minimum (if not to avoid it altogether). Some scientific researches reveal it.
One of the main disadvantages of eating canned tuna often is the presence of mercury in this fish. Depending on how much and, above all, the type of tuna you eat, it is possible to consume a greater or lesser amount of this substance, which leads to potential health risks.
Consumption of fish and shellfish accounts for over 90% of human mercury exposure in the United States, and tuna caught in the Pacific Ocean accounts for 40% of this total exposure, according to a study published in Environmental Health Perspectives.
Mercury, which enters the environment due to various types of manufacturing activities, is deposited in lakes, rivers and oceans. From here it obviously enters the life cycle of aquatic organisms. But mercury in the oceans is also a decomposition product of natural organic carbon, according to scientists in the journal Global Biological Cycles.
When mercury enters the water, in both cases, the microorganisms transform it into a highly toxic form called methylmercury that accumulates in the meat of the fish we eat. Methylmercury especially accumulates in larger predators, which is why larger fish, such as tuna, are more risky to eat than, for example, sardines.
Fish therefore they have different mercury levels. Canned tuna has relatively high levels of mercury, so its consumption could potentially become harmful in excess of three servings per week.
According to data from the US Centers for Disease Control and Prevention (CDC), almost everyone has a small amount of methylmercury in their blood (though below the levels that can trigger health effects). But the methylmercury is a powerful neurotoxin, so eating too much fish can actually cause mercury poisoning.
Symptoms include itching or tingling sensation in the toes and hands, muscle weakness, coordination problems, speech and hearing disorders, and reduced peripheral vision.
It should also be emphasized that high levels of mercury in women pregnant they are extremely dangerous and can cause central nervous system disorders in their babies.
How to limit the risks of mercury in fish
The Food & Drug Administration and the Environmental Protection Agency recommend that women and children (over the age of 10) eat two to three servings of fish and shellfish each week, to be chosen from those low in mercury.
To facilitate the choice, they created a table that shows 60 different types of fish, designating them as "best choices" (to eat 2 or 3 times a week), "good choices" (eat 1 serving per week) or "choices to avoid" ( highlighting fish that contain the highest levels of mercury).
However, the Environmental Working Group says such guidelines can put women at risk. In one study, the EWG recruited 254 women of childbearing age from across the United States. They reported eating as much or more fish as the government suggested. The researchers then tested samples of their hair, considering that this is where mercury accumulates and reflects the amount of this metal in the body.
The results showed that nearly 30% of women were over the EPA's safe mercury limit and nearly 60% had more mercury than a stricter limit set by two European institutions. The EWG believes that including canned light tuna in the "best choices" "low-mercury" category is wrong as it "is a significant source of mercury in women's diets," she says.
The presence of mercury is certainly not the only good reason to limit the consumption of tuna. (Also read: 6 good reasons to choose not to eat tuna).
If you still consume tuna, remember to never make this mistake.
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