5 November 2002
folks eating fish feed on mercury too
'Healthy diet' clearly isn't
by Jane Kay
of affluent Bay Area residents who were seeking health benefits
by eating lots of fish found that they were also loading up on toxic
all those eating big, oceangoing fish such as swordfish and tuna
had concentrations of mercury in their blood exceeding a safety
level set by the U. S. Environmental Protection Agency, the study
by a San Francisco physician showed.
findings, published in the current issue of Environmental Health
Perspectives, comes when health regulators are grappling with ways
to reduce the exposure to mercury, an environmental contaminant
that can damage the brain and nervous system.
study is the first to look at mercury levels among middle- and upper-
income people who eat lots of fish for their health.
found that if people eat fish, the mercury goes up. They stop eating
the fish, the mercury goes down. It's that simple," said the
author, Dr. Jane M. Hightower, a doctor of internal medicine at
the California Pacific Medical Center in San Francisco who conducted
conducted the study with her own patients, whom she described as
"coastal affluent," a mix of physicians, CEOs, Internet
executives, lawyers, winery owners and bankers. She says she would
expect the same kind of results in other coastal cities.
think they're doing the right thing by eating swordfish, sea bass,
halibut and ahi tuna steaks. But they just happen to have the highest
content of mercury sold in restaurants and grocery stores,"
enters water or air as waste from mines, power plants and solid-
waste incinerators. Low levels leach out of natural rock. Mercury
accumulates up the food chain, with large fish at the top carrying
the biggest loads.
BEHAVIORAL PROBLEMS IN KIDS The element attacks the brain and affects
the entire nervous system, including contributing to behavioral
problems and loss of intelligence in children. Recent studies link
mercury exposure to impairments of immune and reproductive systems
and cardiovascular disease.
decided to do the study after hearing about a woman who had hair
loss and showed high mercury levels.
screened 720 patients and selected 123 for testing, either because
they were eating lots of fish or fish known to be high in mercury,
or because they had symptoms of mercury exposure, including fatigue,
headache, joint pain and reduced memory and concentration.
the patients reported eating 30 different types of fish, with canned
tuna, salmon, swordfish, halibut and sea bass the most commonly
consumed. Some ate nine fish meals a week, and one ate up to 20
cans of tuna a month.
89 people Hightower used for her statistical evaluation, 89 percent
had mercury levels exceeding the 5 parts per billion recognized
as safe by the EPA and the National Academy of Sciences.
people had blood-mercury levels more than twice the recommended
level, and 19 had blood-mercury levels four times the level considered
safe. Four people had levels greater than 10 times as high as the
study did not try to compare mercury levels in people eating fish
and those not eating fish, or to correlate mercury levels with symptoms,
although some of her patients had disturbing symptoms.
seven children in the study, all had too much mercury, except one
who didn't eat fish.
child had a blood-mercury level of 13 parts per billion. She was
eating two cans of tuna a week, within the guidelines recommended
by the U.S. Food and Drug Administration.
mother reported that she was lethargic, lost verbal skills and forgot
how to tie her shoes.
instructed her ill and high-mercury patients to give up fish for
six months, or eat fish that doesn't accumulate mercury, such as
salmon, sardines, sole, tilapia or small shellfish.
levels fell dramatically in the 67 patients she followed in the
study, with some taking more than 21 weeks to see reductions.
STUDY CALLED IMPORTANT
The EPA's top official studying human exposure and health effects
of mercury, Kathryn Mahaffey, director of the Division of Exposure
Assessment Coordination and Policy, said the study is important.
knew there are some ethnic groups that tend to eat fish more than
others, including populations of Southeast Asians and Native Americans
that fish in urban areas," Mahaffey said.
we thought there was another group of urban consumers who would
have unusually high mercury exposures because they subsist on fish
and aren't limited by income, and choose a large proportion of their
protein from fish because of taste preference or pursuit of health
study confirms that. This is the first study that has borne it out."
resident Susie Piallat, a longtime patient of Hightower's, had been
complaining for years of a flu-like feeling that she couldn't shake.
When tested, her mercury level was 76 parts per billion -- more
than 15 times the federal safety number.
been very health-conscious all my life. I read everything on the
latest medical issues. I'd been eating eight or nine servings a
week of tuna, swordfish, halibut and sea bass, and loading up on
mercury," said Piallat, a former Pan American Airlines sales
took almost a year for my level to drop. Now I feel so much better,"
FDA advisory already prohibits swordfish, king mackerel, tilefish
and shark for women who are pregnant or might get pregnant, nursing
mothers and young children, and limits other cooked fish to 12 ounces
a week for those groups.
CANNED TUNA PINPOINTED
But four months ago, the FDA's food advisory committee recommended
that the agency find out how much canned tuna contributes to the
mercury levels in women, as well as better assess the risk for children
and put out dietary recommendations based on their size.
Bolger, FDA toxicologist, said he didn't know what more the agency
could do regarding monitoring and placing advisories on tuna.
we look at canned tuna consumption, people are not eating as much
as some think they are," Bolger said. "Children don't
eat a lot of fish."
to get a complete and accurate picture of mercury in fish, the FDA
has begun to gather additional mercury tests on 20 species, including
red snapper, orange roughy, saltwater bass and freshwater trout,
disagrees with the FDA that children don't eat fish. "In our
community, our children are eating fish. You see young children
eating sushi. The federally aided food programs include canned tuna,"
favors updating and expanding mercury testing on commercial fish,
as well as more advisories and labeling where fish is for sale.
people eat a lot of fish, they need to know. Most of us can probably
take in mercury in small amounts" because the body eliminates
it. "But we still don't know" said Hightower.
a documented poison. Wherever it's seen, it's been a problem."