Nonabsorbable dietary lipid reduces the absorption of dietary PCBs and increases the excretion of previously absorbed stored PCBs. Absorption of all PCB congeners will presumably be interrupted by nonabsorbable lipid; however excretion will be enhanced only for PCBs that have not been metabolized and also for their lipophilic metabolites. Our study with the nonabsorbable lipid, olestra, in a controlled trial in Anniston residents with elevated PCB levels demonstrated that it is possible to enhance removal of PCBs from the body in the clinically meaningful time frame of 1 year. The rate of disappearance of PCBs in participants who ate 15 g/day of olestra was significantly faster than the rate determined during the 5 years prior to intervention. The rate of disappearance was not changed from the pretrial rate in participants who ingested vegetable oil. Consideration of the role of body weight and fat is an important factor in the design of intervention trials of this kind, and the results of this trial suggest that the level of body fat in individuals will influence the rate of removal from the body. Previously reported data from animals and from a case report indicate that weight loss combined with nonabsorbable dietary lipid will maximize removal of PCBs and presumably other stored organochlorine compounds. The design of future intervention trials should include a focus on body fat levels and changes. Future trials should also include the testing of dietary compounds other than olestra that have affinity for PCBs, such as plant-derived polyphenols.
Keywords: Anniston; Body burden; DDE; DDT; Half-life; Olestra; PCBs.