New research showing that that mercury levels are higher in some species of tuna could help consumers minimize their consumption of the silvery metal in their sushi and provide a powerful new tool for regulatory organizations.
The new research—combining DNA barcoding at that American Museum of Natural History with analysis of mercury content at Rutgers University—is published in Biology Letters early online edition and shows surprisingly that tuna sushi purchased in supermarkets might be healthier than that from restaurants. The sushi made for supermarkets tends to be yellowfin tuna.
"We found that mercury levels are linked to specific species," says Jacob Lowenstein, a graduate student affiliated with the Museum. "So far, the U.S. does not require restaurants and merchants to clarify what species they are selling or trading, but species names and clearer labeling would allow consumers to exercise greater control over the level of mercury they imbibe."
"People who eat fish frequently have a particular need to know which species may be high in contaminants," says Michael Gochfeld, professor at Robert Wood Johnson Medical School. "Some agencies have been afraid that any mention of contaminants will discourage people from eating any fish.Sushi samples for this research project were taken from 54 restaurants and 15 supermarkets in New York, New Jersey, and Colorado. The results are based on 100 samples, all of which were identified with DNA barcoding as either bigeye tuna (Thunnus obesus), yellowfin tuna (Thunnus albacares), or bluefin tuna species (Thunnus maccoyii, Thunnus orientalis, and Thunnus thynnus). All samples were tested for relative mercury content.
But there also seem to be other factors in play. Although yellowfin tuna is very lean, this species tends to have lower accumulation of mercury, likely because yellowfin are typically smaller than other tuna and are harvested at a younger age. Furthermore, yellowfin are tropical and do not thermoregulate like the warm-blooded bigeye tuna and bluefin tuna. Because bigeye and bluefin species eat three times more than yellowfin to maintain their energy level, they might bioaccumulate, or slowly increase the level of toxins over time.
"Although levels are highest in top-level predatory fish, some fish that are lower on the food chain have high levels," says Joanna Burger, professor at Rutgers University. "The levels of mercury in some tuna are sufficiently high to provide a health risk both to the fish themselves and to the predators that eat them, including humans, particularly those who eat fish frequently."
"We show how you can use DNA as a tool to uncover patterns of species-specific bioaccumulation," says Sergios-Orestis Kolokotronis, a geneticist at the Sackler Institute for Comparative Genomics at the Museum. "This is one of first applications of DNA barcodes in a non-academic setting—using this method in any human health context and not just for determining whether barcodes can quickly and accurately identify a species."
In addition to Kolokotronis, Gochfeld, Burger, and Lowenstein, authors include George Amato, director of the Sackler Institute for Comparative Genomics at the Museum, and Christian Jeitner of the Environmental and Occupational Health Sciences Institute at Rutgers University. This research was funded by the Alfred P. Sloan Foundation, the Richard Lounsbery Foundation, Columbia University, Rutgers University, and the National Institute for Environmental Health Sciences. The New York Times' food editor Marian Burros collected 20 of the samples for a story on mercury in sushi which were later barcoded and included in this analysis.
Kristin Elise Phillips | EurekAlert!
A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich
New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
20.02.2017 | Materials Sciences
20.02.2017 | Health and Medicine
20.02.2017 | Health and Medicine