Study finds students at university consuming potentially dangerous amounts of mercury-rich tuna

A university in the U.S. has erected signs warning students about the dangers of eating too much tuna after a study revealed widespread overconsumption on campus.

Through a combination of a survey and the testing of hair samples, the researchers at UC Santa Cruz found that young learners were helping themselves to far more than the recommended amounts of fish.

Tuna contains the heavy metal mercury in its most toxic form (methylmercury), which can cause neurological damage if consumed in high quantities.

The scientists determined that a person weighing 140lbs should eat no more than two meals a week containing lower-mercury tuna (skipjack and mongol tuna, usually labelled “chunk light”) and no more than one meal a week containing higher-mercury tuna (albacore and yellowfin).

But some of the students at Santa Cruz reported eating more than 20 servings of tuna a week.

"It doesn't necessarily mean that they would be experiencing toxic effects, but it's a level at which it's recommended to try to lower your mercury exposure," said Myra Finkelstein, associate adjunct professor of environmental toxicology at the university.

"Our results were consistent with other studies of mercury levels in hair from people who eat a lot of fish."

She added: "I've been dumbfounded when students have told me they eat tuna every day.

"Their lack of knowledge about the risk of exposure to mercury is surprising."

Finkelstein said the problem could be present at “all kinds of institutions” where dining halls – particularly those serving children – operate.

"Any time you have a dining hall situation where people are helping themselves, some residents may be eating way too much tuna," she said.

The study has been accepted for publication in the journal Environmental Toxicology and Chemistry.