Dietary influences on urinary excretion of hydroxyphenanthrenes, thioethers and mutagenicity in man.

Our study indicates that large differences in dietary polycyclic aromatic hydrocarbon (PAH) content in humans are not reflected by urinary and faecal excretion of hydroxyphenanthrenes, although significant increases in 3-hydroxybenzo[a]pyrene and 3-hydroxychrysene in faeces were observed after consumption of a diet rich in PAHs. The question therefore arises whether urinary hydroxyphenanthrenes are a reliable marker for exposure to PAHs. As expected, the elevated mutagenicity of the diet rich in PAHs led to increased mutagenic activity in urine. The increased urinary excretion of thioethers after this diet was probably due to its higher thioether content. Therefore, an elevated thioether excretion does not always indicate exposure to electrophilic compounds.