- Subjects must agree to abstain from dietary sources of glucosinolates and isothiocyanates beginning three days prior to study and throughout duration of the active study (28 days). Participants will be asked to keep a food diary. A list of food and supplements to abstain from is provided in Appendix A. Patients will be asked to record instances of accidental ingestion of these foods, with patients being removed from the study if this occurs 7 or more times.