INTRODUCTION: Almost all seafood contains mercury in varying amounts, and getting too much of it can damage the brain and nervous system. That is especially true for fetuses, but children and adults who eat too much high-mercury seafood can also suffer harmful effects.
In June 2014, the Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) came out with proposed guidelines recommending that pregnant and breastfeeding women, women who might become pregnant, and young children eat more fish.
We are concerned that consumers who follow these latest government guidelines without careful attention to which species they are consuming could end up taking in too much mercury.
Using FDA data that measure mercury levels in various types of seafood, we developed three lists: “Lowest Mercury Fish,” “Low Mercury Fish,” and “Higher Mercury Fish.” We identified almost 20 seafood choices that can be eaten several times per week, even by pregnant women and young children, without exceeding the reference dose set by the EPA. We also considered environmental and sustainability concerns and did not include on our recommended list types of fish that are low in mercury but caught or farmed in ways that can cause major environmental damage.
We also took a close look at tuna, which is one of the most popular seafood items in the U.S. Given its popularity and mercury content, canned tuna accounts for 28 percent of Americans’ exposure to mercury, according to a 2007 analysis by an EPA researcher.
We disagree with the FDA and EPA on how much tuna women and children should eat. Given the potential harm to a fetus, we recommend that pregnant women and those thinking about becoming pregnant should not eat any tuna for the duration of their pregnancy.
Consumers can use our recommendations to choose seafood wisely. The choices on our “lowest mercury” and “low mercury” lists can be eaten several times per week without worrying about mercury exposure. And our chart on page 10 shows how much tuna a person can safely eat, based upon body weight.