ABSTRACT
94Polychlorinated biphenyls (PCBs) are polyhalogenated aromatic hydrocarbons that are persistent and widely dispersed in the environment. Diet is the major route of exposure to PCBs, and PCBs distribute themselves into tissues, especially adipose, where they are in dynamic equilibrium with blood. Excretion of PCBs from the body is very slow, resulting in an increased PCB body burden with age. PCBs have broad adverse effects, including cancer induction, immune system suppression, nervous system effects, disruption of normal hormone function, and developmental and reproductive abnormalities, as well as increased cardiovascular and inflammatory diseases. PCBs stimulate the production of reactive oxygen species through metabolic events and via cellular signaling pathways. PCBs may also lower the levels of enzymatic and nutrient antioxidants. A resulting imbalance in the cellular oxidative stress or antioxidant status may be a common denominator in PCB-induced disease processes. There is evidence that diet and selected nutrients can modify the cytotoxicity of PCBs. For example, certain dietary fats can upregulate, and nutrients with antioxidant properties can downregulate, cellular signaling pathways involved in PCB-mediated cell dysfunction. This chapter provides evidence that nutrition can modify PCB toxicity, which may have critical implications in numerous age-related diseases such as cancer, cardiovascular disease, or neurological disorders. Nutrition may affect risk assessment of environmental contaminants beyond PCBs. Thus, proper nutrition counseling should be considered by health officials and the medical community to reduce the overall risk for environmental hazards such as PCB toxicity and disease development. More research is needed to understand observed interactions of PCB toxicity with nutritional interventions.
