Occurrence and thyroid hormone disrupting effects of food-borne chlorinated paraffins

Summary

Chlorinated paraffins (CPs) are chemicals used in industries and consumer products in large amounts. These pollutants have been reported in food samples, but data for the Netherlands are missing. The thyroid hormone (TH) system was identified as a target for CPs in rats, but possible relevance for humans and modes of action related to TH disturbance remained unclear. The aim of this thesis was to investigate CP levels in vegetable oils collected from the Dutch market and to provide insight into modes of action related to TH disturbance by CPs by studying their effects in in vitro assays. The results revealed that CPs were present in vegetable oils (medium chain CPs were more abundant than short chain CPs). The refinement reduces the levels of CPs in vegetable oils. Furthermore, short chain CPs were able to compete with thyroxine (T4) to bind to TH distributor transthyretin and induce T4 glucuronidation in human liver HepaRG cells, which at current exposure levels were estimated to not be affected in humans.