NCT07086833 · Purdue University
The Food Environment, Microbial Cysteine Metabolism, and Cancer Disparities
What this study is about
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.
View original scientific description
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.
Interventions
OTHER
Low Cysteine Diet
A diet low in cysteine, about 1.4 g/1000 kcal.
OTHER
High Cysteine Diet
A diet high in cysteine, about 3 g/1000 kcal.
Primary outcome measures
Colonic inflammation
Time frame: Baseline, Week 1 (Day 8), Week 2 (Day 15), Week 4 (Day 29), Week 7 (Day 49), Week 8 (Day 57), Week 9 (Day 64), Week 11 (Day 78)
Fecal calprotectin, a marker of intestinal inflammation, will be measured from 100 mg of stool collected at the respective timeframe using a CALPRO Calprotectin ELISA test.
Fecal microbial content
Time frame: Baseline, Week 1 (Day 8), Week 2 (Day 15), Week 4 (Day 29), Week 7 (Day 49), Week 8 (Day 57), Week 9 (Day 64), Week 11 (Day 78)
Microbial genomic DNA will be extracted from stool obtained at the respective timeframe using a Qiagen DNeasy PowerSoil Kit. Genomic DNA will be fragmented using a Covaris S2 and processed into libraries using an Integrated DNA Technologies xGen DNA Library Prep Kit. Final libraries will be pooled and sequenced on an Illumina NovaSeq X using 25B chemistry.
Systemic markers of inflammation
Time frame: Baseline, Week 1 (Day 9), Week 2 (Day 16), Week 3 (Day 23), Week 4 (Day 30), Week 7 (Day 50), Week 8 (Day 58), Week 9 (Day 65), Week 11 (Day 79)
Serum from blood collected at the respective timeframe will be analyzed in triplicate with the Bio-Plex® Precision Pro™ (Bio rad, Hercules, CA) human cytokine 10-plex immunoassay to detect IL-1β, IL-6, IFN-γ, TNF-α, IL-2, IL-4, IL-5, IL-10, IL-12 (p70) and IL-13.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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
- Individuals under the age of 18
Where
- Indianapolis, Indiana
- West Lafayette, Indiana
Collaborators
American Cancer Society, Inc., Indiana University
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 14, 2026 · Source of record for eligibility and locations