"Over the course of the past decade, the Food and Drug Administration (FDA) has had the idea that talking about mercury at all makes people afraid and makes them not want to eat fish," she adds, noting that the seafood industry has had an outsized influence on the FDA's downplaying of mercury's risks to health, hindering the agency's ability to warn against the highest-mercury types of fish to eat as well as its ability to promote one species as healthier or higher in omega-3s than another.
More: 12 Fish You Should Never Eat
At their core, here are EWG's problems with the current dietary guidelines as they stand:
#1: They're too vague with regard to omega-3s.
EWG analyzed the average levels of omega-3s in the 35 most popular seafood species and found that only two, salmon and tuna, would provide a heart patient or a pregnant woman with beneficial levels of omega-3s. In fact, the country's second most popular seafood, shrimp, is so low in omega-3s, you'd have to eat 100 ounces—that's 6.5 pounds!—a week to get 1,750 milligrams (the recommended amount) of omega-3s. Of the 35 fish varieties most popular among Americans, just 14 would provide you with that amount if you were to eat 8 ounces weekly.
The graphic below outlines how much of each of the top 10 most popular seafood species you'd need to eat every week to reap the most benefit.
#2: They completely ignore mercury risk.
Many of the 21 species that do contain high levels of omega-3s also contain high levels of mercury, which can pose threats to developing brains and to patients at risk of cardiovascular disease; high levels of mercury in fish could interfere with your body's response to stress, which could promote inflammation, a leading cause of heart disease. Even regular people, not pregnant and with health hearts, can suffer neurological and kidney problems from excessive mercury levels.
The Dietary Guidelines claim that the benefits of eating fish far outweigh any health problems associated with mercury, a claim that EWG says is "dangerously out of step with the scientific evidence from dozens of observational studies." Research on American pregnancies, the report states, has found that mothers with mercury levels that are lower than what the Environmental Protection Agency (EPA) considers "safe" still had children who showed signs of mercury damage. And the EPA's most recent assessment of mercury exposure among women who eat more than six seafood meals each month had the highest blood-mercury concentrations of any group.
"The FDA is in the process of improving its guidelines to encourage more fish consumption," Lunder says. And although the agency has said that it plans to take into account omega-3 levels, "they've been really closemouthed about how they're going to deal with mercury."
More: How to Know Which Tuna Is Most Toxic
#3: If all Americans followed the government's recommendations, the world's fisheries would practically collapse.
Fish consumption could double or triple, and Lunder notes that fish farming and sustainable wild-fisheries management techniques are simply not capable of feeding that demand without serious damage to aquatic ecosystems. "It's kind of an unrealistic expectation," she says.
So which types of fish should you be eating? EWG compiled the chart below to help you find fish species that are high in omega-3s, low in mercury, and sustainable, and you can also visit the nonprofit's new website for more information.