Recruiting

Low Sulfur Diet

Sponsor:

University of Michigan

Code:

NCT05849012

Conditions

Crohn's Disease in Remission

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Low Sulfur Diet

Usual Diet

Study Details

Brief summary:

The goal of this study is to learn about a low sulfur diet in patients with Crohn's disease. Study participants will be randomized to receive a low sulfur diet or usual diet for 8 weeks. Participants will work with study nutritionists and receive dietary educational materials. Participants will attend 2 in-person visits as well as 6 phone visits during the study. In addition, subjects will undergo testing, including a test to measure rectal sensation, a test to look for small intestinal bacterial overgrowth, and a test to measure leaky gut.

Conditions

Crohn's Disease in Remission

Study ID

NCT05849012

Start date

Dec 12, 2023

Status verified date

Jan, 2026

Completion date

Apr 30, 2027

Anticipated

Primary completion date

Dec 30, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Prior diagnosis of Crohn's disease based on endoscopic, radiographic, and/or histologic findings
  • Quiescent Crohn's disease as defined by fecal calprotectin level less than 150 micrograms/gram (mcg/g) stool and/or absence of inflammation on colonoscopy within 30 and 90 days, respectively, of enrollment
  • Persistent symptoms will be defined by abdominal pain and/or diarrhea T-scores greater than or equal to 55 by the National Institutes of Health (NIH) Patient-Reported outcomes measurement information system Gastrointestinal scale (PROMIS-GI)

Exclusion Criteria:

  • Prior total colectomy
  • Presence of an end ileostomy or colostomy in place
  • Changes in immunosuppressive medications within the past 4 weeks
  • Use of antibiotics or probiotics within the past 4 weeks
  • Active or suspected stricture/stenosis of the GI tract
  • Habitual vegetarian or vegan diet
  • Active or suspected gastrointestinal stricture or stenosis
  • Unable or unwilling to follow a low sulfur diet
  • Patients who are underweight as defined by BMI < 18.5 kg/m2 or have significant unintentional weight loss as defined by >7.5% body weight in the past 3 months
  • Currently pregnant, breastfeeding, and/or unwillingness/inability to use contraception start of the study until the last 13C-mannitol:lactulose test is complete. Sexually active male participants and/or their female partners of reproductive potential must agree to use effective contraception from the start of the study and until the last 13C-mannitol:lactulose test is complete. Women who are breastfeeding must stop breastfeeding during and for at least 12 hours after consuming the 13C-mannitol:lactulose test. Breastfeeding women must pump and dispose of the breastmilk during this time period
  • Subjects must agree to not donate sperm or ova (eggs) or breast milk from the start of the study until the last 13C-mannitol:lactulose test is complete.

Study Design

Enrollment

20 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Low Sulfur Diet

Participants in this group will follow a low sulfur diet. This diet decreases the amount of animal products (including meat, dairy, and eggs) as well as sulfur additives in the diet. The main types of foods in the low sulfur diet include fruits, vegetables, whole grains, nuts, seeds, and soy products.

active comparator: Usual Diet

Participants in this group will follow a standard of care usual diet for 8 weeks.

Interventions

Low Sulfur Diet

Subjects will be placed on a low sulfur diet for 8 weeks with the support of a nutritionist.

In addition, participants will be asked to complete: surveys, lactulose-mannitol test, glucose hydrogen breath test, blood samples, visceral sensation test, 24-hour urine sample for sulfate level, provide stool samples, optional colonoscopy.

Usual Diet

Subjects will continue on their usual diet for 8 weeks. At the end of 8 weeks, if participants are interested, they will be offered treatment with low sulfur diet for 8 weeks with the support of a nutritionist.

In addition, participants will be asked to complete: surveys, lactulose-mannitol test, glucose hydrogen breath test, blood samples, visceral sensation test, 24-hour urine sample for sulfate level, provide stool samples, optional colonoscopy.

Primary outcome measure

  • Dietary Protein Intake for both groups as assessed by 24 hour diet recall [ Time Frame: 8 weeks ]
  • Dietary Protein Intake as assessed by 24 hour diet recall [ Time Frame: Approximately 16 weeks ]
  • Change in 24 hour urinary sulfate [ Time Frame: 8 weeks ]
  • Change in 24 hour urinary sulfate [ Time Frame: Approximately 16 weeks ]

Central Contacts and Locations

Central contacts

Allen Lee, MD, MS

734-936-9454allenlee@umich.edu

Merrick Bay

merricb@med.umich.edu

Locations

University of Michigan

Recruiting

Ann Arbor, Michigan, United States, 48109

Contacts

Allen Lee, MD, MS

734-936-9454allenlee@umich.edu

Principal Investigator:

Allen Lee, MD

More Information

Sponsor

University of Michigan

Last update posted

Jan 15, 2026

Last verified

Jan, 2026

Keywords

  • Crohn's disease
  • Quiescent Crohn's disease
  • Low sulfur diet
  • Microbiome

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of Michigan on 2026-01-15.