Mercury In Canned Tuna: 5 Things To Know About This Health Scandal

There is poison in the fish. This is the alarming conclusion of a study conducted by the association Bloom on 148 cans of tuna from the ten largest supermarket chains in Europe. In a report published at the end of October 2024, this NGO revealed that all the canned tuna it analyzed are contaminated with mercury. Here are 5 things to know about this new health scandal.

1- The Bloom association is sounding the alarm

"Poison in tuna!" It was with this shocking message posted on X that the association Bloom and the consumer protection organization Foodwatch alerted consumers about the contamination of canned tuna by mercury.

This new health scandal, which broke out in the media at the end of October 2024, is the result of 18 months of investigation by the NGO Bloom.

The association raised the alarm after analyzing 148 cans of tuna from the ten largest supermarket chains in Europe, including France, Germany, England, Spain, and Italy. They found that all the cans, without exception, are contaminated with mercury, a toxic substance dangerous to human health.

2- 100% of canned tuna boxes are contaminated.

Let me warn you right away: there is no point in buying one brand over another in the hope of avoiding mercury contamination in tuna! According to tests conducted by an independent laboratory for the NGO Bloom, 100% of the analyzed cans are contaminated with this heavy metal.

Even worse, 10% of the cans exceed the current tolerated standard for fresh tuna (1 mg of mercury per kilo), and 57% of the analyzed cans exceed the strictest maximum limit (0.3 mg per kilo) set for other fish species and considered the most protective for human health.

Among the 148 cans analyzed by the NGO, one brand in particular shows a record level of heavy metal: Petit Navire tuna. With 3.9 mg per kilo, it contains 13 times more than the most restrictive standard of 0.3 mg/kg!

3- The current standards are not protective enough.

As part of this investigation, the association Bloom condemns the method used in Europe to set maximum mercury levels in tuna.

According to this NGO, "the maximum levels [...] currently in force in Europe have been established based on the contamination rate of observed tuna and not based on the danger that mercury poses to human health." The aim of this maneuver would be to ensure the sale of 95% of the tuna.

The desire to maximize sales, even at the expense of consumer health, would explain why tuna benefits from a maximum mercury tolerance three times higher than that of the least contaminated species (1 mg/kg compared to 0.3 mg/kg for other fish like cod, for example).

Also according to the NGO Bloom, "due to the dangers posed by regular mercury ingestion, even at low doses, all canned goods exceeding the 0.3 mg/kg standard should be banned from sale." Indeed, this heavy metal is no less toxic if ingested via tuna rather than through another fish...

4- Mercury is a neurotoxic substance.

The revelations of the NGO Bloom are chilling when one considers the toxicity of mercury for human health and more specifically for the brain and nervous system...

This study confirms that tuna is one of the most contaminated fish with methylmercury, a derivative of mercury produced in the ocean by microorganisms. It is a form of heavy metal that concentrates in fish and shellfish and is then easily absorbed by our bodies.

In humans, this toxic substance has deleterious effects on the central nervous system, particularly during in utero development and early childhood. It can cause behavioral disorders and developmental delays in children who have been exposed during pregnancy or after birth.

In response to the potential risks to human health, an online petition has been launched by the association Foodwatch: it calls on the European Commission to apply the maximum content of 0.3 mg/kg to fresh and canned tuna. It also urges major European retailers to remove cans of tuna from their shelves, cease all advertising for this product, and inform the public about the associated health risks.

5- It is possible to limit one's exposure to methylmercury.

If this new health scandal worries you, know that it is possible to limit your dietary exposure to methylmercury by taking a few precautions.

According to Anses, the first preventive measure is to diversify the species of fish you consume. Indeed, large predatory fish at the top of the food chain are more contaminated than smaller fish.

It is not about completely banning fish from your diet, as this food is otherwise beneficial for health, being a source of protein and omega-3s. To enjoy its benefits without too much exposure to mercury, here are the official recommendations from Anses for adults:
• Consume fish a maximum of twice a week.
• Vary the fish by consuming a fatty fish rich in omega-3 (such as salmon, sardine, mackerel, or herring) and a lean fish (such as hake, whiting, cod, or sole).
• Diversify fish species and sources, alternating between wild and farmed fish and varying fishing locations.

At-risk individuals, namely pregnant or breastfeeding women and children under 3 years old, should limit their consumption of tuna and other predatory fish that are likely to be highly contaminated. Predatory fish include bonito, ray, dorado, sea bass, monkfish, emperor fish, halibut, and pike.

According to a report by the Biodiversity Research Institute from September 2023, haddock and salmon are the two fish species with the least mercury and can therefore be consumed without specific restrictions.