Do daily high (4 tablets) or intermediate (2 tablets) administration of the broccoli-based dietary supplement Avmacol® have improved bioavailability over a broccoli sprout beverage rich in sulforaphane and its biogenic precursor, glucoraphanin? The beverage formulation has been used successfully in the investigators' previous intervention studies in regions of China with high levels of air pollution to reduce the body burden of carcinogenic and toxic pollutants. The investigators seek to evaluate a more stable, less expensive formulation of a broccoli sprout preparation that can be used for disease prevention in future studies.

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:

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

Exclusion Criteria:

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

Individual participant data (IPD) that underlie results in a publication

Upon completion of biomarker analyses (January 2020)

Placebo control