Monday, February 19, 2007

Fish as Brain Food: To Eat or Not to Eat

While it has been widely recognized by the Food and Drug Administration (FDA) and the Environmental Protection Administration (EPA) since 2004 that pregnant women should not eat more than 340 grams (12 ounces) of fish a week because of the danger of mercury poisoning, recent news addresses the benefits of consuming fish during pregnancy, contradicting this well-established view. Mercury is a toxin found in fish and seafood, and can damage the nervous system, especially in growing fetuses. At the same time, fish and seafood are rich sources for nutrients like omega-3 fatty acids, which are essential to brain maturation. This poses a difficult dilemma regarding the decision to consume fish, and whether it is a friend or foe to development.

Dr. Joseph Hibbeln of the National Institutes of Health conducted a study published just last week monitoring the eating habits of almost 12,000 pregnant women in Britain. After tracking the developmental progress of the children born through age eight, the researchers found that women who ate more than 340 grams per week of fish “had smarter children with better developmental skills.” Hibbeln and his colleagues assessed issues including the children’s social and communication skills, their hand-eye coordination, and their IQ levels. According to, eating more than the FDA and EPA recommended amount of fish during pregnancy benefited the children’s brain development, suggested in the picture below, while children whose mothers ate no fish were 48 percent more likely to have a low verbal IQ score. Another article adds that in addition to low verbal IQ scores, these children may face “suboptimum performance on tests of social behavior, fine motor activity, communication, and social development.” In addition, Jennifer Warner of WebMD describes in 2006 a study that showed that pregnant mothers who took fish oil supplements as opposed to olive oil supplements improved their baby’s hand-eye coordination and brain development, based on tests taken when the children reached age two and a half.

So in light of these results it seems as though pregnant women who eat less than the government recommended levels of fish may be causing more detriment than aid to their child. It is possible that limiting fish consumption will reduce the intake of necessary nutrients like long-chain fatty acids, shown below, to aid children’s neurological and cognitive development. As indicated by Dr. Gary Myers, there is little evidence to back up the FDA’s advisory to limit seafood consumption while pregnant. He states that “it is very clear that omega-3 fatty acids are very important for brain development, [and] it is less clear that mercury at the levels you get from eating fish poses a risk.” But in saying this it is important to understand that one must keep a balanced view and consider not just the factors that improve health, such as the beneficial effects of the nutrients in fish, but also the risks that could be potentially harmful, including eating fish with mercury. While it is promising that the study did not find evidence of increased harm from eating fish, thus challenging government advice that limiting seafood intake is of great value, one still must be cautious and skeptical in interpreting the results of the study because of its self-report nature. And after all, one may be apprehensive to ignore and defy FDA and EPA suggestions simply based on one study's results, since these suggestions are put in place for the purpose of protecting the public’s health and well-being.

Because of this contradicting evidence, one may still be confused about the decision to eat fish or not, specifically regarding pregnant women. Should one eat fish and take the risk of possibly ingesting mercury in order to improve a child’s cognitive development, or should one be safe and avoid all fish even if it may mean lower IQ scores in the child? Even if there is no clear-cut answer, it might be feasible to reach a happy medium. For example, WebMD reporter Salynn Boyles states that pregnant women can abide by FDA and EPA warnings to avoid shark, swordfish, king mackerel, or tilefish, which are more likely to have high mercury levels, but still eat other fish low in mercury. These include shrimp, salmon, canned light tuna (not albacore tuna), and catfish. Pregnant women ought to be well-informed about the levels of both mercury and omega-3 fatty acids in certain fish, as indicated by the graph, in order to make an educated decision about which they should eat. Until a definitive answer can be made as to the better option, individuals must make the choice suitable to their own beliefs. In the meantime, we hope the FDA will maintain its obligation to promote public health, while psychologists simultaneously continue to search for new knowledge and findings.

No comments: