A surprising number of students eating in university dining halls have been helping themselves to servings of tuna well beyond the amounts recommended to avoid consuming too much mercury, a toxic heavy metal.

Researchers at UC Santa Cruz surveyed students outside of campus dining halls on their tuna consumption habits and knowledge of mercury exposure risks, and also measured the mercury levels in hair samples from the students. They found that hair mercury levels were closely correlated with how much tuna the students said they ate. And for some students, their hair mercury measurements were above what is considered a "level of concern."

"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, an associate adjunct professor of environmental toxicology at UC Santa Cruz. "Our results were consistent with other studies of mercury levels in hair from people who eat a lot of fish."

Neurological effects

Tuna and other large fish contain significant amounts of mercury in its most toxic form (methylmercury), and exposure to high levels of methylmercury can cause neurological damage. Because of its effects on neurological development and reproductive health, concerns about mercury exposure are greatest for pregnant women and children. Finkelstein said college students should also limit their exposure to mercury because their nervous systems are still developing and they are of reproductive age.

Read more at University of California - Santa Cruz

Image: Tuna and other large fish contain significant amounts of mercury in its most toxic form (methylmercury). In a survey of college students, half of the tuna eaters reported eating three or more tuna meals per week, potentially exceeding the EPA's 'reference dose' for mercury. (Credit: Nick Gonzales)