The Food Environment, Microbial Cysteine Metabolism, and Cancer Disparities

Inclusion Criteria: * Aged 45-75 * Up to date with CRC screening colonoscopy with a high risk of CRC, defined as a history of 3 or more adenomatous polyps (APs) or an AP \>1 cm in the past 5 years * Identify as Black or Non-Hispanic White * If female, no menstrual period for at least six months * Willingness to donate oral wash and stool samples * Willingness to complete 24-hour dietary recalls Exclusion Criteria: * Antibiotic use within the last 6 months * Abnormal gastrointestinal transit * A history of organ transplantation * Use of illicit drugs, combustible tobacco, or dietary supplements * Pre- or probiotics within the last two months * A history of cancer treatment within the past 12 months * CRC or a genetic predisposition to CRC * A baseline body weight \> 450 lbs * Weight gain or loss \> 4 kg 3 months prior to study * Significant food allergies, food preferences or therapeutic or vegetarian diets * Menstrual cycle within the last 6 months * Antibiotics in the last 2 months * Cannot keep a food record for 7 consecutive days during screening after detailed instruction * Significant medical conditions * History of eating disorders * Alcoholism * Individuals under the age of 18