Title : Prenatal omega-3 levels needed for optimal brain development require new fish consumption advice

Fish consumption during pregnancy has long been the subject of public policy interventions in many countries.  The interventions primarily involve consumption advisories designed to influence pregnant women directly, and through health care providers, nutritionists and dieticians, to limit their fish consumption.  Their purpose is to protect unborn children from methylmercury, a naturally occurring neurotoxin in the marine environment that accumulates in fish.  Early in this century subtle adverse associations between methylmercury and children’s neurodevelopment were reported in the Faroe Islands when pilot whales were consumed during pregnancy.  The pilot whales contained methylmercury and other neurotoxins.  These findings raised concerns that adverse effects might be occurring from mothers’ consumption of fish during pregnancy. To determine whether this was happening, long-term studies involving fish consumption would be needed in populations large enough to reveal subtle associations. In their absence early in this century, the limits in the advisories were essentially precautionary “best guesses” reflecting an abundance of caution.  They remain the basis of today’s advisories.  Now, over 30 long-term fish consumption studies with over 300,000 mother-child pairs have found no harm to children’s neurodevelopment even when amounts of fish substantially exceeded advisory limits.  In addition, the studies have found that children often score better on tests of neurodevelopment, including IQ, when their mothers eat more fish during pregnancy compared to children whose mothers eat little or no fish.  A nutritional explanation for these findings is that the fish provided these children with more DHA and EPA and possibly other key nutrients in utero than the children received from mothers ate little or no fish. DHA and EPA are essential to normal brain development and function.  The primary dietary source for people is fish.  It is not clear whether pregnant women are aware of these developments.  Instead of optimizing DHA and EPA by eating more fish, they are often influenced by the advisories to suboptimize their intake by reducing fish consumption or eliminating it entirely.  Public health interventions are designed to benefit health, but this precautionary intervention has had significant unintended consequences.  A new intervention is needed with advice that clearly explains the unique nutritional relationship between fish, DHA and EPA, and their children’s brain development. It must also reassure them that harm has not been found.

Philip Spiller retired from the U.S. Food and Drug Administration in 2014.  As Director of FDA’s Office of Seafood, he led the development of preventive safety controls for seafood processing and an assessment of the “net effects” on children’s neurodevelopment from eating seafood during pregnancy.  Net effects took into account the total contents of fish, including both omega-3 fatty acids and methylmercury.  FDA’s approach was adopted by an Expert Consultation on fish consumption convened by the WHO and FAO.  After his retirement he co-authored a systematic review and other articles on the effects of fish eaten during pregnancy.