Broccoli Supplement Dose Response

The investigators will conduct a 3-armed placebo-controlled 16-day intervention with the dietary supplement Avmacol® to determine the bioavailability with repeated dosing of a simple tablet-based intervention in the study participants. As shown in Scheme 1, the 3 arms are: 1) 4 tablets of Avmacol® daily for 14 days; 2) 2 tablets of Avmacol® daily for 14 days together with 2 placebo tablets to maintain parity in consumption; and 3) 4 placebo tablets daily for 14 days. In addition, all participants will receive 4 placebo tablets for 2 consecutive run-in days prior to commencing intervention in the 3 distinct arms. Consecutive overnight (12-hour) urine samples will be collected during the 2-day run-in, the 14-day intervention and during a 5-day run-out period (total = 21 days). Additional day-time urine collections will be made at 2 timepoints: the day after administration of Avmacol® tablets begins and the day after the last administration of Avmacol® tablets. A blood sample will be collected at the beginning of the run-in and after the last Avmacol® dose (Day 17 for intervention groups, and for the placebo group) from each participant. The tablets will be taken before dinner each day.

Inclusion criteria

• Age ≥ 21 and ≤ 70 years who are residents of Qidong, China.
• Able to provide written, informed consent.
• Normal physical examination and medical history indicative of good general health with no history of chronic illness.
• No hepatomegaly by clinical exam;
• Normal liver function tests (ALT, aspartate aminotransferase (AST), bilirubin);
• Normal renal function tests (creatinine, blood urea nitrogen (BUN), urinalysis);
• Serum alpha-fetoprotein (AFP) negative.

Exclusion criteria

• Pregnant (positive human chorionic gonadotropin (HCG) strip test)
• Current or former diagnosis of cancer, with the exception of non-melanomatous skin cancer.