In its October 2014 issue, Consumer Reports will publish an analysis of the U.S. Food and Drug Administration’s (FDA’s) data that supported the agency’s recommendations for fish intake by pregnant women and children, released jointly as draft guidance with the U.S. Environmental Protection Agency (EPA) in June 2014. The magazine compiled a list of low-mercury—including haddock, trout, catfish, and crab—and lowest-mercury fish—including shrimp, tilapia, oysters, and wild and Alaska salmon—and detailed the amounts considered safe for consumption for young children and women of childbearing age. The guide includes more conservative advice than the draft guidance from FDA and EPA, such as recommending that most women and young children avoid marlin and orange roughy in addition to the listed swordfish, shark, king mackerel, and gulf tilefish. The magazine cites Deborah Rice, co-author of the EPA document that established the current limit on methylmercury consumption as 0.1 microgram per kilogram of body weight per day. Rice now believes that this limit is too high, pursuant to several studies reportedly showing that adverse effects can occur at lower mercury blood levels.

Consumer Reports also recommends that pregnant women do not eat tuna, departing again from the draft guidance. Even canned light tuna can contain high levels of mercury because those levels can vary greatly from can to can; as the magazine reports, “FDA’s data show that 20 percent of the samples it tested since 2005 contained almost double the average level the agency lists for that type of tuna. And the highest level of mercury in its samples of canned light tuna exceeded the average mercury level for king mackerel.” A recent study from the University of Hawaii at Manoa found similar results for Chilean sea bass. Peter B. Marko, et al., “Seafood Substitutions Obscure Patterns of Mercury Contamination in Patagonian Toothfish (Dissostichus eleginoides) or “Chilean Sea Bass,” PLoS ONE, August 2014. Researchers tested fish purchased at retail seafood counters in 10 different states and apparently found that several of the fish were mislabeled as to the source and breed. Lead researcher Peter Marko argued that fish from uncertified sources were substituted, and the uncertified fish tended to have “very high mercury.” Additional information about the FDA and EPA draft guidance appears in Issues 525 and 526 of this Update.