Fish intake and risk of human exposure to environmental chemicals

Abstract

Methylmercury (MeHg) and persistent organic pollutants (POPs), such as dioxins and polychlorinated biphenyl (PCB), are bioaccumulative chemicals that are considered to be toxic contaminants. Recent studies raise health concern for the toxic effects of combined exposure to these chemicals on child development. These environmental contaminants are found in fish and seafood. On the other hand, fish consumption is largely recognized as beneficial for brain development of children during the gestation period and early infancy. Long-chain omega-3 polyunsaturated fatty acids (omega-3 PUFA) are believed to be responsible for these beneficial effects. In this context, the balance of toxicological and nutritional aspects of fish consumption is highlighted. The aim of this article is to review the negative health effects of the exposures to MeHg, PCB, and dioxins. Current epidemiological evidence, including the three studies performed in Japan, suggests that perinatal exposure to the chemicals can adversely influence child development. This article also reviews the advisories issued by the Japanese governmental agencies. Although several environmental chemicals are demonstrated to be toxic even at the levels observed in Japanese pregnant women, exposure standards are still under active debate. Furthermore, because of lack of epidemiological evidence on the beneficial effects of omega-3 PUFA on child development, the recommendation on fish consumption remains largely undetermined.