French Schools Banned Canned Tuna: What Are the Risks?

Several French cities have banned canned tuna from school menus, citing high levels of heavy metal mercury. So, does it mean that children should stay away from this popular seafood? We asked three registered dietitians.

Eight cities, including Paris and Lyon, have removed canned tuna from school canteens, French media reports. The move came following a study that revealed high mercury concentrations in these products.

Mercury is a heavy metal commonly found in seafood. Consuming high amounts of mercury can lead to poisoning, which can cause symptoms like impaired movement, such as walking or writing, muscle weakness, and skin rashes.

In infants and children, exposure to high levels of methylmercury–the most toxic form of mercury–can cause neurological effects like decreased measures of intelligence, difficulty in memory and cognition, and problems with motor skills.

The study conducted by campaign groups Bloom and Foodwatch tested randomly selected 148 tins from five European countries. All cans were found to contain mercury, and 57% exceeded the strictest maximum mercury limit of 0.3 mg/kg defined for fish in the European Union.

One can purchased in Paris contained 13 times more mercury than the level for species subject to the most restrictive limit.

Safe tuna consumption for children

Canned tuna is among the top three most popular seafoods in the United States, thanks to its convenience and long-lasting shelf life. However, some types of tuna may have some of the highest mercury concentrations.

Understanding the different types of canned tuna is key to making safe choices for children and families, says Pamela Mitri, RD at JM Nutrition.

Canned light tuna is typically made from smaller, younger species such as skipjack, yellowfin, and tongol, which contain significantly less mercury than larger tuna.

"Some caution is needed with canned albacore, also called 'white tuna,' which comes from older, larger fish and can accumulate much more mercury," Mitri tells WellnessPulse.

Janelle Bober, MS, RDN at Dietitian Live, recommends limiting albacore consumption to no more than 4 to 6 ounces a week, especially for children or those who are pregnant.

Another approach is limiting portions, Bober says. For example, having 2 to 3 servings of low mercury fish like tuna, but keeping portions small and less frequent, especially when aiming to stay on the safer side of consumption.

"Check your labels and brands and make sure that you're staying up to date on any recalls. Choose brands that disclose mercury testing. They are required to do mercury testing, but make sure that you're choosing brands with transparency, or smaller fish like the skipjack tuna," Bober tells WellnessPulse.

Serve tuna with a health-supporting overall diet, which includes fruits, vegetables, legumes, and whole grains, according to Kezia Joy, RND at Welzo. Such a diet will help support overall health and provide children with various nutrient-dense foods and sources.

Low-mercury alternatives to canned tuna

Canned tuna can be part of a healthy diet, as it is a good source of omega-3 fatty acids, which support heart health.

A can of tuna contains 41 g of protein, significantly contributing to the recommended daily amount of 46 grams for women and 56 grams for men. However, the amount may depend on physical activity levels and body weight, among other factors.

Moreover, a can of tuna provides about 17% of the recommended daily vitamin D intake, 9% of iron, and 9% of potassium.

Mitri says families looking for nutritious and lower-mercury seafood alternatives can consider fish that provide similar nutrients without the same mercury concerns, such as

1. Salmon (fresh, frozen, or canned)
2. Herring and Atlantic mackerel
3. Rainbow trout
4. Pollock, hake, or char

Bober says sardines canned with bones provide the same type of benefits—omega-3 fatty acids, calcium, vitamin D, and protein—while being very low in mercury.

When preparing canned tuna, drain the liquid to get the most accurate serving size, Mitri recommends.

"If you are seeking plant-based options, beans, lentils, and chickpeas will provide protein and fiber, while walnuts and chia seeds can provide healthy omega-3 fatty acids, so you can still be healthy without consuming fish," Joy tells WellnessPulse.

The takeaway

Although some French schools banned canned tuna from their cafeterias, registered dietitians say there are ways children can safely enjoy this popular seafood. Experts recommend choosing light canned tuna over albacore and serving it with other nutritious foods like vegetables and whole grains.