It's a conundrum: You know seafood is one of the healthiest foods you can eat. Rich in protein and other essential nutrients, swimming with heart-healthy omega-3 fatty acids and low in saturated fats, these watery wonders have likely been a part of your weekly—if not daily—diet for years. But now that you're pregnant, you're being pummeled with news that fish may not be so healthy after all. What gives?
Virtually all experts agree that seafood is an important part of every person's diet, even—and, some say, especially—during pregnancy. Others warn that eating too much seafood when pregnant can potentially lead to dangerous levels of methyl mercury (a toxin that collects in streams, oceans and, ultimately, fish) in the mother's body, raising the risk of neurological damage to her developing fetus. Confused? So were we. To help sort out the issue, we went to some of the foremost experts and researchers in the field. Here's the latest information on this vexing topic.
Warnings: more harm than good?
All seafood contains some amount of mercury. Citing concerns about the possibility of a link between this toxin and impaired language, memory, cognitive thinking and fine-motor and visual-spatial skills among children who were exposed to it in utero, the U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) have established fish-intake guidelines for women who are pregnant or might become pregnant (and, later, when nursing). These agencies don't recommend avoiding seafood altogether, but they do suggest steering clear of varieties with the highest mercury content and limiting the consumption of all others. Here's a recap of their advisory:
• Avoid large, predatory fish such as shark, swordfish, king mackerel and tilefish. (As big fish eat smaller fish, the larger, longer-living ones accumulate more mercury.)
• Eat up to 12 ounces a week of a variety of fish and shellfish that are lower in mercury, such as shrimp, canned light tuna, salmon, pollock and catfish.
• Albacore tuna has more mercury than light tuna, so limit your intake to 6 ounces (one average meal) per week.
• Before eating any non-commercial seafood (such as that caught by family or friends), check with your local branch of the EPA or health department to make sure the water it was taken from is safe. If this information isn't available, eat up to 6 ounces per week of this fish, but don't eat any other seafood that week.
Good intentions aside, the problem with these guidelines, experts say, is that many women have become so confused and frightened that they are now eating too little seafood—or, in some cases, have stopped eating it altogether. "The mercury advisory, which was intended to be very selective, has really caused unintentional confusion," says Dariush Mozaffarian, M.D., DrPH, an assistant professor at Harvard Medical School and a cardiologist at Brigham and Women's Hospital, both in Boston.
"Although women aren't getting this message, the advisory recommends that only four species of fish be avoided entirely, that one species (albacore tuna) be limited to once a week and that all others be eaten," adds Mozaffarian, who is a co-author of a 2006 study on the benefits of seafood. "What's more, both the FDA advisory board and our study say that women and young children in particular should include fish in their diet."
Why is seafood so important during pregnancy? "The long-chain omega-3 fatty acids found in fish, especially DHA, are essential for brain development," says Gary J. Myers, M.D., a professor of neurology, pediatrics and environmental medicine at the University of Rochester Medical Center in Rochester, N.Y. "The body does not manufacture adequate amounts of these fatty acids, so they must be obtained from dietary sources. During pregnancy, a fetus can only get adequate amounts from its mother."
There are other potential benefits to consuming fish as well: "Some data show that eating sufficient amounts of seafood during pregnancy also helps prevent preterm birth and leads to developmental benefits and higher IQ," says Emily Oken, M.D., M.P.H., a primary care physician at the Fish Center for Women's Health at Brigham and Women's Hospital and an assistant professor at Harvard Medical School. "There also is some evidence of a lower risk of asthma and allergies later in life."