It is a conundrum for many pregnant women to choose between forgoing fish in order to protect their unborn children from potential mercury exposure, and eating fish for the sake of consuming omega-3 fatty acids and other beneficial nutrients that promote proper fetal development. But a new study recently published in the online version of the journal Archives of Pediatrics & Adolescent Medicine suggests that sticking with low-mercury fish can actually help pregnant women achieve the best of both worlds when it comes to ensuring their babies are born healthy and strong.
Back in 1993, researchers from both Brigham and Women’s Hospital (BWH) and Boston University‘s School of Public Health set out to determine the relationship between mercury exposure and fetal development by collecting hair samples from several hundred women who had just given birth. The team, led by Dr. Susan Korrick, M.D., and Dr. Sharon Sagiv, Ph.D., also asked the mothers to fill out a questionnaire indicating fish consumption patterns throughout their pregnancies.
After eight years had passed, the team followed up with the mothers and their children to compare fish consumption patterns with both mercury rates and rates of attention deficit hyperactivity disorder (ADHD) among the children. Upon analysis, the team determined that, overall, the risk of ADHD-related behavioral problems was higher among children born to mothers with higher mercury levels observed in their hair samples.
Low-mercury fish found to decrease risk of ADHD
On the flip side, mothers who consumed high amounts of fish during pregnancy also bore children with a decreased risk of ADHD-related conditions, illustrating the relative importance of eating fish during pregnancy. Since fish was shown to play an important role in proper fetal development, particularly due to the nutritional profile of fish oil that has been shown in previous studies to promote brain development and maturation, the study suggests that smart fish consumption is appropriate for pregnant women.
“These findings underscore the difficulties pregnant women face when trying to balance the nutritional benefits of fish intake with the potential detriments of low-level mercury exposure,” explained Dr. Korrick about the findings. “Women need to know that nutrients in fish are good for the brain of a developing fetus, but women need to be aware that high mercury levels in some fish pose a risk.”
Previous studies have found that fish with the highest levels of mercury on average include shark, swordfish, king mackerel and tuna. Fish with lower mercury levels include flounder, haddock, and salmon. As always, wild fish is preferred to farmed fish, and the nutritional profiles of wild fish are generally superior, and the meat generally exposed to fewer toxins.
“All fish has some mercury in it, but there are very different levels,” added Dr. Sagiv. “Eating fish is good for you, but eating fish that is high in mercury is not.”
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