San Francisco Chronicle
5 November 2002

Rich folks eating fish feed on mercury too
'Healthy diet' clearly isn't
by Jane Kay

A study of affluent Bay Area residents who were seeking health benefits by eating lots of fish found that they were also loading up on toxic mercury.

Nearly 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.

The 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.

The study is the first to look at mercury levels among middle- and upper- income people who eat lots of fish for their health.

"We 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 the study.

Hightower 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.

"They 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," Hightower said.

Mercury 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.

Hightower decided to do the study after hearing about a woman who had hair loss and showed high mercury levels.

She 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.

Overall, 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.

Of 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.

Sixty-three 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 government recommends.

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.

Of seven children in the study, all had too much mercury, except one who didn't eat fish.

One 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.

Her mother reported that she was lethargic, lost verbal skills and forgot how to tie her shoes.

Hightower 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.

Mercury 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.

"We 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.

"But 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 benefits.

"Hightower's study confirms that. This is the first study that has borne it out."

Tiburon 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.

"I've 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 manager.

"It took almost a year for my level to drop. Now I feel so much better," said Piallat.

The 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.

Michael Bolger, FDA toxicologist, said he didn't know what more the agency could do regarding monitoring and placing advisories on tuna.

"When 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."

Yet, 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, Bolger said.

Hightower 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," she said.

Hightower favors updating and expanding mercury testing on commercial fish, as well as more advisories and labeling where fish is for sale.

"If 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.

"It's a documented poison. Wherever it's seen, it's been a problem."