Research, by a San Francisco internist who studied Californians who ate large amounts of fish, has found that 89 percent of those examined ended up with elevated levels of mercury in their bodies. Associated Press reported on the findings by Dr. Jane Hightower released 19 October at a Burlington, Vermont conference jointly sponsored by the U.S. Environmental Protection Agency (EPA) and the American Fisheries Society (AFS).

Hightower's is one of the first studies to document mercury levels in Americans who eat more fish than the EPA recommends. The peer-reviewed study is slated for publication on I November in the journal Environmental Health Perspectives.

Too much mercury damages the nervous system, especially in children and fetuses, but scientists are not certain how much mercury-tainted fish is needed to trigger health problems.

78 percent of the patients with high mercury levels reported eating canned tuna more than three times a month; 74 percent ate salmon more than four times a month; and 72 percent said they had swordfish more than once a month.

Other fish commonly eaten by the patients included halibut, ahi, sea bass and various types of sushi.

The U.S. Food & Drug Administration (FDA) recommends that pregnant women and young children limit their fish intake to two 6-ounce cans of tuna per week if it's the only fish they eat, and to one can per week if they also eat other fish. FDA says they should not eat any swordfish, shark, king mackerel or tilefish.

The study did not address physical symptoms such as fatigue or memory loss associated with mercury poisoning. Some patients did report such problems, but Hightower's study did not seek to correlate symptoms with mercury levels.

"It is a thorny problem because of the widely recognized benefits of fish, a high quality protein source loaded with heart-protecting Omega 3 fatty acids," said the AP report. "Conference participants didn't seem panicked about the findings: The majority ordered salmon for dinner Saturday -- though salmon is considered among the safest types of fish to eat."

To see the AP story, go to: http://story.news.yahoo.com/news?tmpl=story&u=/ap/20021020/ap_on_he_me/mercury_menace_5.

Meanwhile, in a study of 1,674 elderly people living in France, researchers from the University Victor Segalen in Bordeaux found the incidence of dementia was a third lower among those who ate fish every week.

The study, published in a British medical journal, was reported on 25 October 2002 in an article by health editor Jeremy Laurance. The study found, however, that those who ate fish were better educated and when this was taken into account the link with dementia was slightly reduced.Dementia tends to be more common in people of lower IQ who use their brains less.

The study's authors believe fatty acids in fish could reduce brain inflammation and may have a role in brain development and nerve cell regeneration. Fat has long been suspected of playing a role in dementia by causing thickening of the blood vessels in the brain or clots that block the tiny capillaries, damaging brain cells.

Fish, which is high in polyunsaturated fats, has been thought to have a protective effect on the brain similar to that on the heart.

Elderly people who ate fish or shellfish at least once a week were significantly less likely to suffer dementia, including Alzheimer's disease, than those who did not, but eating meat neither increased nor decreased the risk.

The finding echoes U.S. research suggesting that a diet low in fat and high in anti-oxidants found in green vegetables, fruit and whole grains, as well as fish, reduces the risk of Alzheimer's disease.