Healthy Habits: Pregnancy, Fish, Mercury, and Healthy Fats

Pregnant women who follow the federal government's draft dietary advice could eat too much fish high in toxic mercury, which is harmful to the developing brains of fetuses, babies and young children, according to a new EWG study of women nationwide. At the same time, they could fail to get enough of the omega-3 fatty acids essential to their babies’ healthy development.

EWG tested hair samples from 254 women in 40 states who eat two or more seafood meals per week, about the same as recommendations under consideration by the Food and Drug Administration and the Environmental Protection Agency. The tests found that nearly 30 percent exceeded the current EPA safety guideline for mercury exposure during pregnancy.

But although the women in the study eat more than twice as much fish as the average American, for almost 60 percent the seafood they ate didn't supply enough omega-3s for an optimal pregnancy. The study shows that during pregnancy women should not only watch how much fish they eat, but what kind of fish.

Click here to read the full report: U.S. Fish Advice May Expose Babies to Too Much Mercury

“These are savvy, health-conscious women who thought they were making the right choices, so they were shocked to find high levels of mercury in their bodies," said Sonya Lunder, the study's author and a senior analyst at EWG. “What's more, the fish they ate didn't provide enough omega-3s. The seafood advice from the FDA and EPA should be much more detailed and specific, to help women balance the harm from mercury and the benefits of omega-3s.”

Philippe Grandjean, an adjunct professor of environmental health at the Harvard T.H. Chan School of Public Health, whose students analyzed the mercury in the hair samples of the EWG study participants, said it's critical to inform pregnant women of the risks of mercury exposure.

“Women who are or plan to become pregnant need a balanced diet that includes fish and seafood to obtain sufficient omega-3 fatty acids, but it should be with minimal mercury contamination,” Grandjean said. "Our research has shown that mercury exposure from eating contaminated fish carries serious health risks, especially for the developing fetal brain, and we should do our best to protect the intelligence of the future by avoiding mercury.”

Watch Dr. Philippe Grandjean and Kyra Norsigian, a study participant from Boston, Mass., talk about the new study.

“Federal guidelines fall short on protecting women who are pregnant or planning to have children,” said Michael Bender, director of the Mercury Policy Project. “Based on the evidence, it’s time for FDA and EPA to revise their advice, particularly when it comes to reducing tuna consumption, since it’s the largest mercury exposure in the American diet.”

The study found elevated mercury exposure for women who ate a lot of sushi, and predatory ocean fish like swordfish, marlin, shark or tuna, which tend to have more mercury because they’re larger and higher on the food chain. To make better choices, EWG’s Good Seafood Guide and Seafood Calculator help people select fish and shellfish that are lower in mercury, higher in omega-3 fatty acids and sustainably produced.