To determine whether glucobrassicin-rich Brussels sprouts can favorably modify the metabolism of the polycyclic aromatic hydrocarbon deuterated phenanthrene ([D10]phe) in current and former smokers

Subjects will be given 1 microgram of [D10]phe, and all urine will be collected for 6 h afterwards to quantify baseline levels of [D10]phenanthrene tetraol ([D10]pheT) and [D10]phenanthrols ([D10]HOP). Within 3 days of this baseline measurement, subjects will consume 200 micromoles of glucobrassicin in the form of raw Brussels sprouts (~200-300 grams) at the study center once daily for 7 consecutive days. Urine will be collected for 24 h after vegetable consumption on days 3 ± 1 and 6 of the feeding intervention for 3,3'-diindolylmethane (DIM) quantification. On day 7 of the feeding intervention, a second dose of 1 microgram of [D10]phe will be administered at the study center after vegetable consumption, followed by another 6 h urine collection.

Inclusion Criteria:

• Adult ≥ 18 years old
• Current or former smoker by self-report
• Willing to abstain from cruciferous vegetable consumption other than the study vegetable during the study period
• Able to understand the experimental nature of the study and provide informed consent
• Negative urine pregnancy test for women of childbearing potential within 7 days of baseline [D10]phe dosing

Exclusion Criteria:

• Chronic proton pump inhibitor, H2-blocker (i.e., ranitidine, famotidine), and/or calcium carbonate use
• History of gastric bypass surgery, gastric banding, bowel resection, malabsorption syndromes such as celiac sprue or pancreatic insufficiency, or other conditions that may affect gastric absorption
• Current use of tobacco products other than cigarettes (i.e. snuff, snuz, smokeless tobacco, cigars, pipes) or use of these products within 3 months of study registration
• Major or chronic medical disease, including heart disease, poorly controlled diabetes, etc., to be adjudicated by the principal investigator
• Women who are pregnant, intend to become pregnant within 3 months of the study period, or who are breastfeeding
• Current or recent (within 12 months) problems with drug use or alcohol dependence by self-report Antibiotic use within 2 months of study enrollment or during the study by self-report Alcohol dependence, abuse, or history of dependence/abuse by self-report Vegetarians
• History of respiratory tract cancer
• Use of metronidazole or antabuse during the study
• Taking ibuprofen, naproxen, other NSAIDs, steroids (except inhaled steroids) within 14 days of study registration
• Allergy to Brussels sprouts