by Amanda Conschafter, blog editor
Many pregnant women embrace eating habits that protect and benefit their unborn babies. But their choices can become complicated when claims from unscientific sources clash with regulatory agencies’ clear, established nutrition guidance. Such is the case with a recent report from the Environmental Working Group (EWG) on the value of fish in a healthy pregnancy diet.
Research and Reservations
The EWG tested hair samples from more than 250 women who reported consuming as much or more fish than recommended by the Food and Drug Administration for women who are nursing, pregnant or trying to become pregnant. Testing results suggested that more than 30 percent of these women had higher levels of mercury in their bodies than deemed safe by Environment Protection Agency standards.
The EWG study’s design, however, could belie its data:
- Participants’ fish consumption was measured by self report, which can lack validity. The EWG admitted that its seafood intake estimates should “be interpreted with caution.”
- The study’s control group was paltry, with only 29 participants, and the findings were not peer reviewed.
- Some participants admitted to eating fish on FDA’s “Do Not Eat” list, which FDA advises against precisely because they contain higher levels of methylmercury. The four fish to avoid are shark, swordfish, tilefish and king mackerel.
Accepted Science on Fish Consumption
In contrast, a significant body of scientific research demonstrates that the value of fish consumption for pregnant women outweighs methylmercury risks.
- The FDA’s 2014 Net Effects Report, which examined both the risks and benefits of fish consumption, outlined a nine-year study resting on 120 peer-reviewed studies. Researchers concluded that, “substantial evidence has emerged…[that] consumption during pregnancy can benefit the developing nervous system even though fish contain methylmercury.”
- The Food & Agriculture Organization and World Health Organization determined in 2011 that, given the benefits of omega-3 fatty acids compared with the risks of methylmercury, “maternal fish consumption lowers the risk of [babies’] suboptimal neurodevelopment…compared with the offspring of women not eating fish.”
- The FDA and Environmental Protection Agency’s updated dietary guidance, currently in draft form, encourages pregnant women to eat 2-3 servings of low-mercury fish a week. “The nutritional value of fish is important during growth and development before birth,” the guidance explains, “in early infancy for breastfed infants, and in childhood.”
- The U.S. Departments of Agriculture and Health and Human Services’ 2015 Dietary Guidelines for Americans recommend that pregnant and breastfeeding women consume at least 2-3 seafood meals each week. They also encourage obstetricians and pediatricians to provide guidance on how to make healthy nutrition choices that include seafood.
Policymakers, health care providers and patients alike must be cautious about the quality of research used to shape guidance on fish intake, lest confusion drive risk-averse pregnant women to avoid fish altogether—and forfeit the proven health benefits for both mother and developing baby.