|
 While fish certified by the Marine Stewardship Council (MSC) is
generally considered safe, seafood from regions with high levels of
contamination are not. And researchers studying samples from U.S.
retail stores found that many fish are indeed the species they are
claimed to be, but not from the region claimed.
“Chilean sea bass is already known to sometimes have high mercury
levels,” lead author Peter Marko, of the University of Hawai’i at
Manoa, Honolulu, told Reuters Health.
“If women are pregnant or nursing, they probably shouldn’t buy that
fish, to be safe,” he said.
Past research has found that fish sold in retail markets is not
always the species it’s advertised to be. And that even within a
given species, mercury levels can vary widely.
Methylmercury, the type of mercury found in fish, is an organic
compound that can be absorbed into living tissue.
Pregnant and nursing women and kids have been advised by the U.S.
Food and Drug Administration to avoid shark, tilefish, swordfish and
King Mackerel because these species have a mean mercury level of
0.73 to 1.45 parts per million. The FDA’s limit for mercury in fish
for human consumption is 1.0 ppm.
Normally, the mercury content of Chilean sea bass, also known as
Patagonian toothfish, is 0.35 ppm, according to the FDA.
In the current study, published in the journal PLOS One, researchers
used sea bass tissue samples from retailers in 10 U.S. states. They
measured the total amount of mercury in 25 of the MSC-certified and
13 of the uncertified Chilean sea bass samples.
They found that fish labeled as certified had less than half the
mercury (0.35 ppm) of uncertified fish (0.89 ppm).
But when the researchers excluded the fish that actually belonged to
other species and were not genetically sea bass, they found no
significant difference in the mercury levels of certified and
uncertified fish.
“We then said, ‘that can’t be because certified is supposed to come
from South Georgia, where the mercury level is low, why do we see
such a difference in mercury?’” said Marko, referring to a fishery
area close to the South Pole and known to have less mercury
contamination than fish from waters off South American. “It’s these
fishery stock substitutions,” he said.
The researchers tested the DNA of the fish and found those from
outside the MSC-certified South Georgia/Shag Rocks fishery had twice
as much mercury (0.63 ppm) as those genetically confirmed to be
South Georgia stock (0.31 ppm).
“Regular mercury exposure is potentially dangerous to developing
nervous systems, so this and other studies like it are of greatest
concern to pregnant women, children, and women planning on having
children,” Marko said in an e-mail.
[to top of second column] |
“Our study demonstrates that accurate labeling of seafood – not just
with respect to what species but also what country or region the
seafood came from – is essential to consumers, particularly in the
aforementioned demographic, to make informed choices at the seafood
counter,” he said.
Marko pointed out that fish from South American waters can have
two-to-three times as much mercury as fish from MSC-certified
regions.
Roberta White, professor and chair of Environmental Health at Boston
University School of Public Health, who was not involved in the
study, told Reuters Health in a phone interview the findings were
another reminder that consumers need to be careful when purchasing
fish.
“What’s really disturbing is how do people choose to eat fish that
are safe?” said White, who has studied the effects of industrial
pollutants on the brain.
“Everybody wants people to eat fish because it is good for the brain
and heart, but we also don’t want them to be poisoning their
children because they’re pregnant,” she said.
White said future studies needed to focus on different species of
fish and the genetics within species, as well as variations in
neurotoxicants. Other contaminants in fish could also pose a health
danger, including Polychlorinated Biphenyls (PCBs), which are
synthetic organic chemicals, organic tin and different pesticides,
she said.
“As this article points out, sometimes you think something is safe
because of the way it’s labeled and maybe it isn’t, but that’s true
of all our food,” White said.
“This is where you have to start, the simple stuff,” White said. “I
think what’s important about the study is the public health message
that we need to be careful about this and figure it out,” said
White.
SOURCE: http://bit.ly/1vBpKRH
PLOS One, online August 5, 2014.
[© 2014 Thomson Reuters. All rights
reserved.] Copyright 2014 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed. |
