Message from health experts to pregnant mothers and their young children: It's good to eat your seafood.

Fish and shellfish are a good source of protein, low in saturated fat, and contain other nutrients important to a developing baby.

Even so, those benefits have been obscured by warnings of the dangers from eating mercury-contaminated seafood.

But a growing number of studies have demonstrated that the risks have been exaggerated. And now, the experts have changed their message. With the exceptions of shark, swordfish, king mackerel and tilefish, seafood is good food for mother and young child alike.

Nutritional benefits include omega-3 fatty acids, said Christina Chambers, an expert on fetal development and assistant professor of pediatrics at UC San Diego. Omega-3s help reduce the risk of heart disease and help in fetal development, Chambers said.

A study attesting to seafood's benefits was published Feb. 17 in The Lancet, a British medical journal. The study found that children of mothers with the lowest seafood consumption had the poorest development. The information was collected from 11,875 mothers in Bristol, England.

And The Lancet study is the latest of several such studies. One, published in the Oct. 18, 2006, issue of the Journal of the American Medical Association, found that eating modest amounts of fish was associated with better health in both children and adults. The study was performed by researchers at the Harvard School of Public Health.

That study examined the levels of omega-3 fatty acids, along with contaminants such as mercury, in fish and other foods. It found that eating fish lowered the risk of death from cardiovascular disease by 36 percent, with the benefits linked to "oily" fish with higher levels of omega-3, such as salmon and bluefish, and lesser for lean fish such as haddock and cod.

Even fish with high levels of mercury may not be as dangerous as once thought, according to recent studies.

No evidence was found of any damage from mercury in a study of more than 700 children in the Seychelles Islands. Mothers of these children ate about 10 times as much fish as the average American, and the types of fish they ate were high in mercury content. The study was performed by researchers at the University of Rochester Medical School and released at the February 2006 meeting of the American Association for the Advancement of Science.

Source of fear

Mercury, specifically methylmercury, got its fearsome reputation as a child destroyer due to a disaster in the seaside Japanese town of Minamata, Chambers said. Large quantities of mercury-laden waste were dumped into Minamata Bay, which then got into the fish consumed by residents.

In the late 1950s, numerous people in Minamata began exhibiting signs of a strange disease. They would stumble, have trouble using their hands, lose hearing or display other symptoms such as uncontrollable shaking or shouting. Even cats had difficulty walking. This was later found to be nerve damage from mercury poisoning. Worse, children were found born with what became known as "Minamata disease." Some were born blind, deaf, developmentally disabled or deformed.

Trying to avoid a repeat of this disaster, health scientists urged the public to be wary of fish and seafood consumption. The problem was that there was no way to be certain what level of mercury carried an elevated risk of poisoning. Experiments on humans could not be done for ethical reasons. So animal studies and examination of those who showed symptoms of mercury poisoning had to suffice.

Conservative guidelines

As a result, the health experts established standards for fish consumption that erred on the conservative side. The warnings to pregnant women had the intended effect. However, Chambers said the warnings didn't fully consider that seafood has nutritional benefits. So the real issue is not how to avoid risks, but how to balance risks and benefits.

It's complicated, Chambers said, because you have to consider not only the species of seafood, but where it came from. She recommends looking for any health advisories at the Web sites of the federal Environmental Protection Agency or Food and Drug Administration.

Online help

More information about eating seafood safely is available online.

A federal advisory on mercury and seafood is available at http://tinyurl.com/2su6w6. Information on how to select and prepare seafood safely is available at http://tinyurl.com/3doq24. General information on food safety for pregnant mothers is available in English and Spanish at http://tinyurl.com/7gkau.

The state of California also offers advice for women who are planning for pregnancy or who are already pregnant. They can get free help from the California Pregnancy Risk Information Line at (800) 532-3747. For more information, visit the service's Web site at http://ctispregnancy.org.

Contact staff writer Bradley J. Fikes at (760) 739-6641 or bfikes@nctimes.com.

The U.S. Food and Drug Administration and Environmental Protection Agency have issued joint guidelines for women who might become pregnant, those who are pregnant. and small children regarding fish consumption. The guidelines state:

- Do not eat shark, swordfish, king mackerel, or tilefish because they contain high levels of mercury.

- Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury. Five common seafood low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.

- Another commonly eaten fish, albacore ("white") tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.

- Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.