Mediterranean Diet and Time-Restricted Feeding in Ulcerative Colitis Remission

Official title

Mediterranean Diet and Time-Restricted Feeding Intervention to Improve Gut Health, Quality of Life and Inflammation in Patients With Ulcerative Colitis in Remission: A Pilot Randomized Controlled Trial

Overview

This study will evaluate whether a 12-week dietary intervention can improve gut health, inflammation, and quality of life in adults with ulcerative colitis in remission. Participants will be randomly assigned to one of three groups: a Mediterranean diet, a Mediterranean diet combined with time-restricted feeding (eating within an 8-hour window each day), or standard dietary advice. The Mediterranean diet emphasizes fruits, vegetables, whole grains, legumes, nuts, olive oil, and fish, while limiting processed foods and red meat. The main outcome will be changes in short-chain fatty acids in stool samples, which are markers of gut health. Additional outcomes include changes in inflammation markers, gastrointestinal symptoms, and quality of life. The results of this study may help identify effective dietary strategies to support patients with ulcerative colitis.

Detailed description

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by periods of remission and relapse, associated with alterations in the gut microbiota, immune dysregulation, and impaired intestinal barrier function. Current treatments focus on controlling inflammation; however, there is a growing interest in non-pharmacological strategies, including dietary interventions, to improve disease outcomes and quality of life.

The Mediterranean diet has been associated with anti-inflammatory effects, improved gut microbiota composition, and increased production of short-chain fatty acids (SCFAs), which play a key role in maintaining intestinal homeostasis. Time-restricted feeding (TRF), a form of intermittent fasting that limits daily food intake to a specific time window, has shown potential metabolic and anti-inflammatory benefits in preclinical and human studies. However, evidence on the combined effects of these interventions in patients with UC is limited.

This study is a pilot randomized controlled trial designed to evaluate the effects of a 12-week intervention with a Mediterranean diet alone or in combination with TRF on gut health, inflammation, and quality of life in patients with UC in remission.

A total of 45 participants will be randomized in a 1:1:1 ratio into three groups: (1) Mediterranean diet, (2) Mediterranean diet combined with TRF (16-hour fasting and 8-hour eating window), and (3) standard dietary advice (control group). Nutritional plans will be individualized and isocaloric.

Participants will be assessed at baseline, week 6, and week 12. The primary outcome is the change in fecal SCFA levels, measured using gas chromatography. Secondary outcomes include changes in fecal calprotectin, C-reactive protein, gastrointestinal symptoms, and quality of life assessed by validated questionnaires.

This study aims to generate preliminary evidence on the effectiveness and feasibility of combined dietary interventions in UC, supporting future larger-scale clinical trials.

Interventions

• Behavioral Mediterranean Diet
  Participants will receive individualized nutritional counseling to follow a Mediterranean diet, emphasizing high intake of fruits, vegetables, whole grains, legumes, nuts, olive oil, and fish, and reduced consumption of red meat and ultra-processed foods. Dietary plans will be tailored to individual energy requirements.
• Behavioral Mediterranean Diet + Time-Restricted Feeding
  Participants will follow a time-restricted feeding protocol (16:8), consisting of a daily 16-hour fasting period and an 8-hour eating window (12:00-20:00). During the eating window, participants will consume meals based on Mediterranean diet guidelines, with individualized dietary counseling to ensure adequate nutritional intake.
• Behavioral Standard Dietary Advice
  Participants will receive standard dietary counseling based on current clinical guidelines for ulcerative colitis. This includes general recommendations for a balanced diet without specific emphasis on Mediterranean dietary patterns or time-restricted feeding.

Primary outcome measures

• Change in fecal short-chain fatty acid (SCFA) levels [Time frame: Baseline to 12 weeks]

Secondary outcome measures (1)

• Change in fecal calprotectin [Time frame: Baseline to 12 weeks]

Eligibility criteria

Inclusion criteria

• Adults aged 18 to 60 years
• Diagnosis of ulcerative colitis
• Clinical remission for at least 6 months
• Fecal calprotectin < 250 µg/g in the last 3 months
• Daily eating window ≥ 11 hours

Exclusion criteria

• Active ulcerative colitis
• History of gastrointestinal surgery
• Liver or kidney disease
• Pregnancy
• Eating disorders
• Use of supplements (protein, antioxidants, probiotics)
• Current restrictive diets (vegetarian, vegan, gluten-free, low-FODMAP)
• High levels of physical activity

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Treatment

Study locations

Chile · 1 center

• Pontificia Universidad Católica de Chile — Santiago

Identifiers

NCT: NCT07752446 · 250706002

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗