Nominated Substances: Indole-3-carbinol
Nomination Date: 04/14/1999
Rationale: Marketed as a dietary supplement. Substantial evidence exists that indole-3-carbinol can reduce the risk of cancers induced by several carcinogens when administered to animals. However, it also induces cytochrome P450 1A1 through the Ah receptor, a process often associated with toxicity. P450 1A1 also metabolizes several known environmental procarcinogens to their carcinogenic form.
NTP Principles: 2