Brain Food: Foreward by EWG president Ken Cook

Foreword

Fish is beyond compare as a source of many nutrients vital to the developing infant, some of which may actually enhance development of the nervous system in babies and young children.

Widespread contamination of fish with toxic mercury, however, has cast a shadow over the nutritional benefits of fish.

Exposure to mercury in the womb can cause learning deficits, delay the mental development of children, and cause other neurological problems. Mercury consumed by a pregnant woman through contaminated fish can cross her placenta to damage the brain of her baby. As a National Academy of Sciences panel definitively warned last year, some children exposed in utero by their mothers' fish consumption are at risk of falling in the group of children "who have to struggle to keep up in school and who might require remedial classes of special education."

Combustion in power plants of coal containing mercury is the major source of environmental pollution. Mercury pollution from coal-fired power plants moves through the air, is deposited in water and finds its way into fish, accumulating especially in fish that are higher up the food chain. Fish like tuna, sea bass, marlin and halibut show some of the worst contamination, but dozens of species and thousands of water bodies have been seriously polluted.

As a result, women who eat a lot of fish during pregnancy, or even as little as a single serving of a highly contaminated fish, can expose their developing child to excessive levels of mercury. The toxic metal can cross the placenta to harm the rapidly developing nervous system, including the brain.

In this report, EWG researchers for the first time attempt to characterize just how common such exposures are in the U.S. population, and the associated risks. One key to the analysis is a much more refined representation of differences among women - their size, metabolism of mercury, blood volume, and many other biological variables. Government assessments use "averages" or constants for all of these factors, missing profound differences across the population of women of child bearing age.

EWG analysts also assembled the most extensive database ever developed on mercury levels in various species of fish, drawing on federal, state and other government sources, some 56,000 records in all. That exercise revealed major variations in mercury contamination across fish species, yielding vital, highly practical information women can use while pregnant to reduce mercury exposure dramatically, while still enjoying the nutritional benefits of fish. Earlier this year, the Food and Drug Administration came up with its own list of fish that pregnant and nursing women, along with infants, should avoid. Based on our analysis of much more extensive fish contamination records, the list presented in this report is more complete.

By analyzing these two data sources in combination, the study is able to provide new insights into how women can avoid excessive mercury exposures during pregnancy.

Researchers at U.S. PIRG Education Fund, co-authors of this study, made another vital contribution. PIRG painstakingly combed through hundreds of "fish advisories" issued by state agencies to warn people about mercury levels in sport and game fish in literally thousands of U.S. lakes and rivers. What they found is disturbing: while some states are doing a better job than others, virtually no fish advisories for mercury contamination are adequately protective of human health when judged against current scientific knowledge.

The importance of this new understanding about mercury risks was evidenced in a landmark study on blood levels of mercury and other toxins, released by the federal Centers for Disease Control and Prevention (CDC) in March, 2001. While "average" blood mercury levels among women were not of concern, the data indicate that in fully 10 percent of American women — roughly 7 million women of childbearing age — mercury levels were above the dose that may put a fetus at risk for adverse nervous system effects. Those women surely don't need more mercury in their system, least of all if they are already pregnant or nursing. As this report recommends, the government must start monitoring such exposures, and any possible effects, much more energetically. This is a simple, common sense matter of public health.

In the longer term, the solution is to halt mercury pollution from coal-burning power plants and other sources so the contamination of fish is avoided in the first place. Fuel switching — from coal to renewable energy sources--along with aggressive deployment of conservation measures, makes sense for any number of reasons. Fish free of mercury — the way they used to be — is just another one.

Kenneth A. Cook
President
Environmental Working Group