Colorectal CancerNCT03550885
Diet Modulation of Bacterial Sulfur and Bile Acid Metabolism and Colon Cancer Risk
A study testing High taurine and saturated fat diet and Low in taurine and saturated fat diet in people with Colorectal Cancer, run by University of Illinois Chicago at 1 site in United States.
Trial summary
Determine in the context of a controlled crossover diet-intervention trial the role of taurocholic acid metabolism by gut bacteria in African American subjects at elevated risk for colorectal cancer (CRC). Read more about this study
- Who is it for?
- Ages 45 to 75 yearsHealthy volunteers can take part
- Conditions the study is for
- Colorectal Cancer
- What is being tested?
- High taurine and saturated fat diet and Low in taurine and saturated fat diet
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 15 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Aug 2018to 1 Dec 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 45 to 75 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adult African American;
- Obese (defined as BMI 30 - < 50 kg/m2);
- Age between 45 - 75 years old;
- Patients with an increased risk for CRC, defined as 3 or more adenomatous polyps or adenomatous polyp > 1cm within 5-yrs of enrollment;
- An elevated C-reactive protein (CRP) (defined as > 3 mg/l)
- Participants must be in good general health, not expecting major lifestyle changes in the next 6 months and willing to maintain their current activity level throughout the duration of the study.
- Women only: Post-menopausal (natural or surgical) defined as no menstruation in the past 6 months
Who cannot join
- BMI < 30 or > 50 kg/m2 (for those interested and eligible, verify BMI by measuring weight and height, complete the screening consent form before assessing these measures)
- Weight > 450 lbs. (max weight for the body composition scanner)
- Race other than African American
- Women only: at least one menstrual period in the past 6 months
- Current malignancy except non-melanoma skin cancer that has been removed
- Current gastrointestinal (GI) illness other than gastroesophageal reflux disease or hemorrhoids (such as celiac disease, inflammatory bowel disease, malabsorptive bariatric procedures, etc.)
Show all 19Show fewer
- Chronic liver or kidney disease (elevated liver tests >3 times normal or creatinine above 2.0 mg/dl)
- History of cardiac disease (such as admission for congestive heart failure within the past 5 years, or being on anticoagulants for heart disease, or having an ejection fraction <25%, etc.)
- Positive genetic test for inherited polyposis syndromes (such as familial adenomatous polyps, hereditary non-polyposis colon cancer syndromes, etc)
- Alcoholism or illicit drug use
- Antibiotic use within the past 2 months
- Regularly taking medications that may interfere with normal digestion (such as acarbose, cholestyramine, Orlistat, aspirin doses that exceed 81mg/day or 325 mg every other day)
- Anticoagulant use or other factors that increase endoscopic risks
- Non-English speaking
- Pregnant or breast feeding
- Dietary supplement use including pre- or probiotics within the past month
- History of intestinal cancer, inflammatory bowel disease, celiac disease, or malabsorptive bariatric surgery
- Inflammatory or connective tissue diseases (such as lupus, scleroderma, rheumatoid arthritis, etc.)
- 21. Prior perforation at colonoscopy or gastrointestinal bleeding due to biopsies of the colon 22. Therapeutic or vegetarian diet 23. Food allergy/aversions to any foods in included in the trial 24. Any medical condition, which, in the opinion of the investigator, could adversely affect the subject's participation in the trial, or affect the trial integrity
Trial locations and contacts
1 site in 1 country.
United States1 site
Rush University Medical Center and University of Illinois at Chicago
Chicago, Illinois, 60612
About this study
Determine in the context of a controlled crossover diet-intervention trial the role of taurocholic acid metabolism by gut bacteria in African American subjects at elevated risk for colorectal cancer (CRC). Two isocaloric diets, an animal-based diet high in taurine and saturated fat (HT-HSAT) and a plant-based, low in taurine and low saturated fat (LT-LSAT) will be used to determine the extent to which the relationship between diet (independent variable) and mucosal markers of CRC risk including epithelial proliferation, oxidative stress, DNA damage, and primary and secondary bile acid pools and biomarkers of inflammation (dependent variables) is explained by the abundance of sulfidogenic bacteria and hydrogen sulfide (H2S) concentrations \&/or deoxycholic acid (DCA) and DCA-producing bacteria clostridium scindens (mediator variables).
Read the detailed description
Our research is designed to determine mechanistically why consumption of a high red meat and saturated fat diet imparts risk for CRC development and to demonstrate that primary microbial risk factors (sulfidogenic and bile acid metabolizing bacteria) are modifiable by diet. The focus is on taurine, an overlooked sulfur amino acid (SAA) that is abundant in red meat or provided by bacterial deconjugation of the bile salt TCA, which is increased in subjects consuming a diet high in saturated fat. Rationale for focusing the diet intervention study on AAs comes from the previously mentioned observation that a taurine respiring bacterium distinguished AA but not NHW CRC patients from healthy controls, and the previous work by PI Gaskins in AA subjects focused on mechanisms underlying the increased risk for CRC associated with consumption of a Western type diet.
Our strong collection of past publications and new preliminary data support our hypothesis that dietary sources of organic sulfur increase the abundance of microbes that generate H2S through taurine metabolism and that H2S activates proinflammatory pathways and serves as a genotoxin in the colonic mucosa. We're examining, for the first time bacteria that utilize taurine, which can be provided directly from red meat or indirectly through TCA in response to saturated fat. Our study will be the first to examine the consequences of such specific dietary manipulation on genotoxic or inflammatory pathways implicated in CRC development in at-risk AAs.
Our results will provide novel information regarding the in vivo interactions between diet and cancer that heretofore have not been explored in humans, particularly AAs. Food taurine content is not currently provided in either the University of Minnesota Nutrition Data System for Research (NDSR) or the USDA Standard Reference (USDA SR) nutrient databases, which are the gold standard sources for the nutrient content of food. Evidence that taurine is capable of inducing biomarkers of CRC risk through promoting growth of Sulfidogenic B. wadsworthia or other untargeted bacteria would be an important novel observation justifying the addition of this SAA to these nutrient databases. If our hypothesis is substantiated, simple vigilance of taurine intake might diminish susceptibility to CRC in all individuals, especially AAs at elevated risk. Further, if our hypothesis is upheld, it might be possible to reduce risk not only by dietary intervention but also by microbiota modification (potentially through pre-, pro- or synbiotics). Finally, if our study reveals particular modes of bacterial sulfur or bile acid metabolism correlating with epithelial proliferation or inflammation in AAs, the endpoints identified can potentially predict non-invasively elevated risk individuals who should be: a) advised on specific dietary interventions (those investigated herein); b) offered specific therapy to reduce risk; or c) counseled on regular colonoscopic screening
- Conditions
- Colorectal Cancer
- Being tested
- High taurine and saturated fat diet, Low in taurine and saturated fat diet
- Keywords
- microbiome, human, bile acids and salts, diet, western
- Medical subject headings
- Colorectal Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High taurine and saturated fat dietOther
This is a 3-week (21 day) isocaloric Western-type diet with all meals, snacks, beverages and condiments provided.
Low in taurine and saturated fat dietOther
This is a 3-week (21 day) isocaloric largely plant-based diet with all meals, snacks, beverages and condiments provided.
| Study group | Role | What they receive |
|---|---|---|
| High taurine and saturated fat diet | Experimental | This is a 3-week controlled isocaloric diet containing approximately 125 mg taurine, 40% of calories from fat, 15% of calories from saturated fat, 25% of calories from protein (4:1 animal to plant grams of protein), and 11.5 grams fiber/1000 calories. Receives: Other: High taurine and saturated fat diet |
| Low in taurine and saturated fat diet | Experimental | This is a 3-week controlled isocaloric diet containing approximately 7 mg taurine, 36% of calories from fat, 8% of calories from saturated fat, 13% of calories from protein (3:1 plant to animal grams of protein), and 13.5 grams fiber/1000 calories. Receives: Other: Low in taurine and saturated fat diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in the mucosal abundance of bacterial genes associated with sulfur and bile acid metabolism
Mucosal abundance of bacterial genes associated with sulfur and bile acid metabolism will be measured by quantitative polymerase chain reaction of 16S rRNA and functional genes with biopsy DNA.
Measured: Baseline and post-diet (day 22) for each of the two 3-week diets
Secondary outcomes (5)
Change in bile acid metabolism
Bile salt hydrolase and bile acid 7a-dehydroxylating activities will be measured in stool samples
Measured: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in serum bile acids
Measurement of serum bile acids using electrospray-ionization mass spectrometry to indicate the extent of taurine-conjugation of bile acids, ratio of conjugated: unconjugated bile acids and levels of secondary bile acids absorbed from the gut
Measured: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in colonic mucosal inflammation
Gene expression of tumor-necrosis factor-alpha, Interleukin-6, and Cox-2
Measured: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in DNA damage
By COMET fluorescence hybridization assay together with in situ staining for 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), an oxidative DNA lesion, and the expression of its repair enzyme 8-oxoguanine DNA-glycosylase (OGG1; ab91421), XRCC1 [33-2-5] ab1838), which coordinates the action of DNA ligase III, polymerase beta, and poly-ADP-ribose polymerase in the BER pathway and the apurinic/apyrimidinic endonuclease Ape1 (ab2717), a multifunctional protein that protects cells from oxidative stress via its DNA repair, redox, and transcription regulatory activities
Measured: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in colonocyte proliferation
Immunohistochemistry, Ki-67
Measured: Baseline and post-diet (day 22) for each of the two 3-week diets
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Jun 2018
- Study start1 Aug 2018
- Primary completion1 Dec 2021
- Study completion1 Dec 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Colorectal CancerStudies of the same condition, open and under way.
- More trials run by University of Illinois ChicagoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- The proposed study will utilize a randomized, crossover, controlled feeding trial design composed of two experimental diets: (1) animal-based, high in taurine and saturated fat (HT-HSAT) and (2) plant-based, low in both taurine and saturated fat (LT-LSAT) (each consumed for 21 days with a minimum 3-week washout between diets). At baseline and post-diet (day 22) for each of the two 3-week diets, subjects will undergo a flexible sigmoidoscopy, fasting and non-fasting blood draw, and provide a stool sample.
- Masking
- Single blind
- Who is masked
- Investigator
- Enrolment
- 15 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Illinois Chicago
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Lisa Tussing-Humphreys, University of Illinois Chicago
- Investigators
- Lisa Tussing-Humphreys, PhD, MS, RD, Principal investigator, University of Illinois ChicagoEce Mutlu, MD, MS, MBA, Principal investigator, Rush University Medical CenterH. Rex Gaskins, PhD, Principal investigator, University of Illinois at Urbana-ChampaignJason Ridlon, PhD, Principal investigator, University of Illinois at Urbana-Champaign
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03550885
- Sponsor's protocol ID
- 2016-0495
- Other IDs
- 1R01CA204808-01
- Status last verified
- Mar 2026
- First submitted
- 24 May 2018
- Last updated
- 6 Apr 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Diet Modulation of Bacterial Sulfur and Bile Acid Metabolism and Colon Cancer Risk
- ClinicalTrials.gov ID
- NCT03550885
- Acronym / sponsor ID
- 2016-0495
- Conditions
- Colorectal Cancer
- Keywords
- microbiome, human, bile acids and salts, diet, western
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 15 participants (actual)
- Lead sponsor
- University of Illinois ChicagoUniversity, hospital or other
- Collaborators
- Rush University Medical Center, National Cancer Institute (NCI)
- Study start
- 1 Aug 2018 (actual)
- Primary completion
- 1 Dec 2021 (actual)
- Study completion
- 1 Dec 2021 (actual)
- First posted
- 8 Jun 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Determine in the context of a controlled crossover diet-intervention trial the role of taurocholic acid metabolism by gut bacteria in African American subjects at elevated risk for colorectal cancer (CRC). Two isocaloric diets, an animal-based diet high in taurine and saturated fat (HT-HSAT) and a plant-based, low in taurine and low saturated fat (LT-LSAT) will be used to determine the extent to which the relationship between diet (independent variable) and mucosal markers of CRC risk including epithelial proliferation, oxidative stress, DNA damage, and primary and secondary bile acid pools and biomarkers of inflammation (dependent variables) is explained by the abundance of sulfidogenic bacteria and hydrogen sulfide (H2S) concentrations \&/or deoxycholic acid (DCA) and DCA-producing bacteria clostridium scindens (mediator variables).
Detailed description
Our research is designed to determine mechanistically why consumption of a high red meat and saturated fat diet imparts risk for CRC development and to demonstrate that primary microbial risk factors (sulfidogenic and bile acid metabolizing bacteria) are modifiable by diet. The focus is on taurine, an overlooked sulfur amino acid (SAA) that is abundant in red meat or provided by bacterial deconjugation of the bile salt TCA, which is increased in subjects consuming a diet high in saturated fat. Rationale for focusing the diet intervention study on AAs comes from the previously mentioned observation that a taurine respiring bacterium distinguished AA but not NHW CRC patients from healthy controls, and the previous work by PI Gaskins in AA subjects focused on mechanisms underlying the increased risk for CRC associated with consumption of a Western type diet.
Our strong collection of past publications and new preliminary data support our hypothesis that dietary sources of organic sulfur increase the abundance of microbes that generate H2S through taurine metabolism and that H2S activates proinflammatory pathways and serves as a genotoxin in the colonic mucosa. We're examining, for the first time bacteria that utilize taurine, which can be provided directly from red meat or indirectly through TCA in response to saturated fat. Our study will be the first to examine the consequences of such specific dietary manipulation on genotoxic or inflammatory pathways implicated in CRC development in at-risk AAs.
Our results will provide novel information regarding the in vivo interactions between diet and cancer that heretofore have not been explored in humans, particularly AAs. Food taurine content is not currently provided in either the University of Minnesota Nutrition Data System for Research (NDSR) or the USDA Standard Reference (USDA SR) nutrient databases, which are the gold standard sources for the nutrient content of food. Evidence that taurine is capable of inducing biomarkers of CRC risk through promoting growth of Sulfidogenic B. wadsworthia or other untargeted bacteria would be an important novel observation justifying the addition of this SAA to these nutrient databases. If our hypothesis is substantiated, simple vigilance of taurine intake might diminish susceptibility to CRC in all individuals, especially AAs at elevated risk. Further, if our hypothesis is upheld, it might be possible to reduce risk not only by dietary intervention but also by microbiota modification (potentially through pre-, pro- or synbiotics). Finally, if our study reveals particular modes of bacterial sulfur or bile acid metabolism correlating with epithelial proliferation or inflammation in AAs, the endpoints identified can potentially predict non-invasively elevated risk individuals who should be: a) advised on specific dietary interventions (those investigated herein); b) offered specific therapy to reduce risk; or c) counseled on regular colonoscopic screening
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (investigator)
- Number of arms
- 2
- Model description
- The proposed study will utilize a randomized, crossover, controlled feeding trial design composed of two experimental diets: (1) animal-based, high in taurine and saturated fat (HT-HSAT) and (2) plant-based, low in both taurine and saturated fat (LT-LSAT) (each consumed for 21 days with a minimum 3-week washout between diets). At baseline and post-diet (day 22) for each of the two 3-week diets, subjects will undergo a flexible sigmoidoscopy, fasting and non-fasting blood draw, and provide a stool sample.
| Arm | Type | Receives |
|---|---|---|
| High taurine and saturated fat diet | Experimental | Other: High taurine and saturated fat dietThis is a 3-week controlled isocaloric diet containing approximately 125 mg taurine, 40% of calories from fat, 15% of calories from saturated fat, 25% of calories from protein (4:1 animal to plant grams of protein), and 11.5 grams fiber/1000 calories. |
| Low in taurine and saturated fat diet | Experimental | Other: Low in taurine and saturated fat dietThis is a 3-week controlled isocaloric diet containing approximately 7 mg taurine, 36% of calories from fat, 8% of calories from saturated fat, 13% of calories from protein (3:1 plant to animal grams of protein), and 13.5 grams fiber/1000 calories. |
Who may qualify
- Ages
- 45 to 75 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- Adult African American;
- Obese (defined as BMI 30 - < 50 kg/m2);
- Age between 45 - 75 years old;
- Patients with an increased risk for CRC, defined as 3 or more adenomatous polyps or adenomatous polyp > 1cm within 5-yrs of enrollment;
- An elevated C-reactive protein (CRP) (defined as > 3 mg/l)
Key exclusion criteria (19 listed)
- BMI < 30 or > 50 kg/m2 (for those interested and eligible, verify BMI by measuring weight and height, complete the screening consent form before assessing these measures)
- Weight > 450 lbs. (max weight for the body composition scanner)
- Race other than African American
- Women only: at least one menstrual period in the past 6 months
- Current malignancy except non-melanoma skin cancer that has been removed
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| High taurine and saturated fat dietThis is a 3-week (21 day) isocaloric Western-type diet with all meals, snacks, beverages and condiments provided. | Other | High taurine and saturated fat diet |
| Low in taurine and saturated fat dietThis is a 3-week (21 day) isocaloric largely plant-based diet with all meals, snacks, beverages and condiments provided. | Other | Low in taurine and saturated fat diet |
Primary outcome
Change in the mucosal abundance of bacterial genes associated with sulfur and bile acid metabolism
Time frame: Baseline and post-diet (day 22) for each of the two 3-week diets
Mucosal abundance of bacterial genes associated with sulfur and bile acid metabolism will be measured by quantitative polymerase chain reaction of 16S rRNA and functional genes with biopsy DNA.
5 secondary outcomes
Change in bile acid metabolism
Time frame: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in serum bile acids
Time frame: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in colonic mucosal inflammation
Time frame: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in DNA damage
Time frame: Baseline and post-diet (day 22) for each of the two 3-week diets
Change in colonocyte proliferation
Time frame: Baseline and post-diet (day 22) for each of the two 3-week diets
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Apr 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Lisa Tussing-Humphreys, PhD, MS, RD principal investigator
University of Illinois Chicago
Ece Mutlu, MD, MS, MBA principal investigator
Rush University Medical Center
H. Rex Gaskins, PhD principal investigator
University of Illinois at Urbana-Champaign
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High taurine and saturated fat diet and Low in taurine and saturated fat diet in people with Colorectal Cancer, run by University of Illinois Chicago at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in the mucosal abundance of bacterial genes associated with sulfur and bile acid metabolism (time frame: Baseline and post-diet (day 22) for each of the two 3-week diets). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Apr 2026.