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The Food Environment, Microbial Cysteine Metabolism, and Cancer Disparities

Who can join

As published by the study on ClinicalTrials.gov. "Not stated" means the study hasn't said — ask the study team.

Age
45 Years to 75 Years
Sex
All sexes
Healthy volunteers
Not accepted
Compensation
Not stated

Other requirements are listed under Eligibility below. Only the study team can confirm whether you can join.

What to expect

No one can promise a trial will help you personally — that is what the research is trying to find out.

What participation involves

  • Time periods mentioned: 11 weeks, 3 weeks, 1 week
  • Procedures mentioned: Questionnaires

Only what the study's summary and detailed description on ClinicalTrials.gov say. Time periods may describe the whole study or a part of it — ask the study team what applies to you.

Show the study's own words
  • "Participants will be in the study for 11 weeks and 2 days."
  • "Over the course of the study, participants will: * Eat a high cysteine diet for 3 weeks, and a low cysteine diet for 3 weeks * Eat a moderate cysteine diet for 1 week before each study diet * Complete surveys * Provide blood, stool, and saliva samples * Maintain food logs"
Compensation
Not stated
  • Study-related exams and procedures are typically provided at no cost. This is how many trials work in general — confirm the details for this study with the study team.
  • Participants are monitored closely by the research team throughout the study.
  • Some participants may receive access to an investigational treatment, which is still being studied.
  • Your participation helps researchers learn whether this approach could help future patients.

About this study

In plain language

This study tests how diets high and low in cysteine, a building block of protein, affect the body, gut bacteria, and swelling or irritation in the gut. It is for Black and non-Hispanic White adults ages 45–75 with a history of certain non-cancerous colon polyps (growths). Each person will try both diets during the study, which lasts 11 weeks and 2 days.

The goal of this clinical trial is to learn if changing cysteine levels in the diet can influence how the body processes cysteine in Black and White individuals aged 45-75 with a history of non-cancerous polyps. The main questions it aims to answer are: * At the beginning of the study, do Black participants have higher levels of cortisol (a stress hormone) and compounds made from cysteine in their blood when compared to White participants? * Does eating less cysteine lower the body's natural cysteine activity and lead to less gut bacteria that break down cysteine? * Does eating less cysteine lead to less inflammation in the gut and lower levels of markers of inflammation in the blood? Research will compare a high cysteine diet and a low cysteine diet, and each participant will eat both diets. Participants will be in the study for 11 weeks and 2 days. Over the course of the study, participants will: * Eat a high cysteine diet for 3 weeks, and a low cysteine diet for 3 weeks * Eat a moderate cysteine diet for 1 week before each study diet * Complete surveys * Provide blood, stool, and saliva samples * Maintain food logs

Compensation is read from the study's own description and may be missing — always confirm with the study team.

Eligibility

Who can join

  • You are 45–75 years old.
  • You identify as Black or non-Hispanic White.
  • You are up to date on colonoscopy screening for colon and rectal cancer.
  • In the past 5 years, you have had at least 3 adenomatous polyps (growths that may turn into cancer), or one larger than 1 centimeter.
  • If female, you have not had a period for at least 6 months.
  • You are willing to give mouth-rinse and stool samples.
  • You are willing to report everything you ate and drank over a 24-hour period.

Who can't join

  • You used antibiotics in the past 6 months, or prebiotics or probiotics (products that feed or contain gut bacteria) in the past 2 months.
  • You use illegal drugs, tobacco that is burned and smoked, or dietary supplements.
  • You have colon or rectal cancer, an inherited risk for it, or had cancer treatment in the past 12 months.
  • You have had an organ transplant, have major medical conditions, or food moves through your gut at an abnormal speed.
  • You weigh more than 450 pounds, or gained or lost more than 4 kilograms (about 9 pounds) in the past 3 months.
  • You have major food allergies or food preferences that limit what you eat, follow a vegetarian diet or a diet for a medical condition, or have a history of eating disorders or alcohol addiction.
  • You cannot keep a food record for 7 days in a row during screening, even after detailed instructions.
  • You have had a period in the past 6 months, or you are under 18.

Simplified for readability. The official criteria below are what the study team uses.

Official eligibility criteria

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

Study sites (2)

IN