An interventional study of Low Cysteine Diet and High Cysteine Diet in Colorectal Cancer, sponsored by Purdue University. Recruiting at 2 sites in United States. Open to participants aged 45 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-05-14.
Sponsored by Purdue University · Not applicable, Interventional, and Prevention
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:
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:
6,541 studies on the registry are indexed under Colorectal Neoplasms; 1,667 are open to participants now.
This study's planned enrollment of 40 is below the median of 76 across 4,800 interventional studies indexed under Colorectal Neoplasms.
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Exclusion Criteria:
Participants will eat a diet higher in cysteine, relying on more animal based protein.
Other: High Cysteine Diet
Participants will eat a diet lower in cysteine, relying on more plant based protein.
Other: Low Cysteine Diet
A diet low in cysteine, about 1.4 g/1000 kcal.
A diet high in cysteine, about 3 g/1000 kcal.
Colonic inflammation
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.
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 microbial content
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.
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)
Systemic markers of inflammation
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.
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)
Quantification of serum hydroxycortisol and cysteine metabolism markers
Serum hydroxycortisol and measures of cysteine metabolism (cysteine, homocysteine, lanthionine, cystathionine, serine) will be determined using hydrophilic interaction liquid chromatography with triple quadrupole tandem mass spectrometry by the Purdue Metabolite Profiling Facility.
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)
Absolute and relative quantification of microbial cysteine metabolic genes
Microbial genomic DNA will be extracted from stool obtained at the respective timeframe using a Qiagen DNeasy PowerSoil Kit. To estimate gene content, metagenomic libraries will be constructed from stool DNA. Metagenomic data will be processed to filter potential host DNA sequences and remove low-quality reads. Raw shotgun data will be assembled using MEGAHIT and assembled contigs will be binned using MetaBAT2. Taxonomic classification of binned contigs will be performed using CAT/BAT and differences genera that have functional genes for sulfur metabolism will be assessed. Assembled and binned metagenomes will be surveyed for genes for cysteine metabolism using custom hidden Markov model (HMM) libraries.
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)
Exfoliated intestinal epithelial cell transcriptomics
Exfoliated intestinal epithelial cells separated from stool collected at the respective timeframe with gene expression analysis
Time frame: Baseline, Week 1 (Day 8), Week 4 (Day 29), Week 8 (Day 57), Week 11 (Day 78)
Psychosocial health
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Time frame: Baseline, Week 4 (Day 30), Week 8 (Day 58),Week 11 (Day 79)
Medication use
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Time frame: Baseline, Week 4 (Day 30), Week 8 (Day 58),Week 11 (Day 79)
Bowel habits
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Time frame: Baseline, Week 4 (Day 30), Week 8 (Day 58),Week 11 (Day 79)
Plan to share: No
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