Commentary: Fish Is Good for You

Published February 1, 2006

Why do the Japanese and the Inuits have some of the lowest risks for cardiovascular disease and heart-related death? Likewise, why are breast cancer rates unusually low in these same groups? Why are rates of postpartum depression relatively lower in Japan, Singapore, Malaysia, Hong Kong, and Chile than in most western nations? Why is the prevalence of Alzheimer’s disease so high in Arab populations in Israel while the risk is significantly lower for the Cree Indians of northeastern Canada?

The best explanation points to differing diets. The healthier populations listed above ingest high levels of nutritious omega-3 fatty acids through consumption of fish and shellfish.

Comparing national daily intakes of these essential fatty acids reveals average Americans consume between 2 to 10 times below rates in Japan, Singapore, Scandinavia, and Spain.

Mercury Scare Takes Toll

So, why are American diets deficient in fish and fish oil? Why aren’t Americans eating more fish?

Our self-imposed consumption restriction is at least partially derived from being confused and alarmed by the daily news barrage claiming available sources of seafood may be overly “contaminated” by the biologically toxic form of mercury, called methylmercury.

For example, recent evidence demonstrates that pregnant women from eastern Massachusetts are consuming less fish following the FDA’s confusing revision of its fish consumption advisory. Also, the latest sales figures for canned tuna report a drop of 10 percent nationwide, compared to 16 months ago. This represents an industry revenue loss of nearly $150 million. More worrisome than financial loss, a further drop in American seafood consumption below an already deficient level is particularly bad news for our most sensitive populations, such as pregnant women, fetuses, and young children.

Science Contradicts Alarmists

Such mercury fears are unfounded in science. The wide variety of ocean fish available to Americans is almost surely safe, with no emerging health threats from the trace levels of mercury. There is nothing in these fish to warrant unnecessary consumption restrictions.

Here is what the best science tells us.

First, the overall health benefits of consuming a variety of ocean and lake fish clearly far outweigh the risk from micro traces of mercury (measured in parts per million) occurring naturally in fish through the synthesis of existing mercury from Earth’s crust, oceans, and rivers. The medical literature richly documents the potential mitigation for a host of serious negative health conditions by the intake of omega-3 fatty acids.

Secondly, widespread claims of modern industrial mercury “contamination” are without scientific support. In sharp contrast, the scientific evidence overwhelmingly points to naturally elevated levels of mercury in both fish and humans.

Third, the recent popular alarmism about damage to child neurodevelopment and adult cardiac health related to mercury are rooted in extrapolations from highly inappropriate studies of populations in the Faroe Islands and eastern Finland, respectively.

Studies Wildly Misinterpreted

The Faroese studies are inappropriate for setting risk levels for the U.S. population because the Faroe Island inhabitants are uniquely exposed to very high levels of mercury from consumption of pilot whale meat. Additionally, Faroese mothers and children are exposed to a cocktail of other toxic chemicals, including PCBs and DDT, by eating pilot whale blubber.

Limited suggestions of cardiac risk from consuming fish with trace levels of mercury is contradicted by numerous studies of documented cardiac health benefits, as noted by the American Heart Association. The Finnish study often referenced by alarmists is almost certainly too unique and poorly designed to suggest any direct relevance for Americans. For example, the rate of cardiac death in eastern Finland is among the highest in the world, likely due to high consumption of animal fat. The authors themselves identified at least eight other risk factors, including vodka and beer binging; low dietary intake of fruits, berries, and vegetables; and vitamin C deficiency. More important is a critical design flaw of the Finnish study: The time lapse for collection of the mercury data can be as long as 10 years before the documented death events, which raises serious questions about misclassification of exposure.

Thus, persistent, exaggerated, and unfounded mercury scares reported in the media could be seriously and irresponsibly endangering the health of all Americans.

Willie Soon ([email protected]) is chief science researcher at the Center for Science and Public Policy.

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