Effect of Preoperative Diet on Perioperative Gut Microbiome

Not Applicable

• Conditions: Surgical Site Infection
• Interventions: Behavioral: high-fiber/low fat; Behavioral: fermented

• Registration Number: NCT05027763
• Lead Sponsor: Stanford University

Brief Summary

The aim of the study is to evaluate the gut microbiome (i.e. bacteria, viruses, and fungi that reside in the gut) of people undergoing abdominal surgery, evaluate whether specific diets can change the gut microbiome, and, if so, whether those changes translate into better surgical outcomes.

Detailed Description

Standard of care: patients undergoing major abdominal colorectal surgery are sometimes advised to eat healthfully prior to surgery, but without more specific recommendations regarding their diet.

Research Activities:

1. Screening: eligible patients will be identified through screening the clinic schedules.

2. Enrollment: in person or remotely, after the patient is determined to require major abdominal surgery, they will be invited to participate in the study. If they consent to participate, they will be randomized to receive either low-fat/high-fiber diet, high-fermented diet, or continue with their normal diet for 10-14 days prior to the surgery.

3. Intervention: at baseline, data will be collected regarding clinical information of the patients (age, body mass index, comorbidities, medications or supplements, physical activity levels, antibiotic or probiotic use in the past six months), and baseline dietary pattern, which will be evaluated through application of a validated Food Frequency Questionnaire (DHQ III). Patients in the intervention arms (low- fat/high-fiber diet or high-fermented diet) will receive meal samples during the 10-14 days preceding surgery. Patients in the control arm will receive a $25 grocery voucher. Adherence to the diet will be assessed through regular check ins with the patients.

Stool samples will be collected in five timepoints: at the beginning of the study, after the dietary intervention, during surgery, in the first week after the surgery, and between 21-30 days after surgery. The stool samples will be sent for analysis of the microbiome.

A fragment of the resected bowel will also be sent for analysis of the mucosal-associated microbiome.

4. Closeout: After surgery, all patients will receive the same standard dietary protocol and care, and will be followed for 30 days without any further intervention.

Basic Information
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Recruitment & Eligibility
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Study & Design
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Trial Locations

Study Timeline

• Study First Submitted: 2021-08-17
• Study First Submitted QC: 2021-08-25
• Study First Posted: 2021-08-30
• Study Start: 2022-03-01
• Status Verified: 2024-03
• Last Update Submitted: 2024-03-26
• Last Update Posted: 2024-03-28
• Primary Completion: 2024-12-01
• Study Completion: 2024-12-01

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 60

Inclusion Criteria

• undergoing major abdominal colorectal surgery with intestinal resection in 2 or more weeks

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Exclusion Criteria

• patients who do not speak English or Spanish
• houseless patients
• decisionally impaired patients
• presence of ileostomy prior to the surgical procedure
• surgery without intestinal resection

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
High Fiber/low fat	high-fiber/low fat	Patients will receive sample meals and education/support, will be asked to follow this diet for 10 days.
Fermented	fermented	Patients will receive sample meals and education/support, will be asked to follow this diet for 10 days.

Primary Outcome Measures

Name	Time	Method
Change in gut microbiome alpha and beta diversity according to pre-operative diet intervention	Two weeks prior to surgery	Metagenomic sequencing will be performed on stool samples before and after dietary change.

Secondary Outcome Measures

Name	Time	Method
Frequency and severity of surgical complications according to pre-operative diet	30 days after surgery	Comprehensive Complication Index (CCI) score will be used to measure number and severity of surgical complications occurring within 30 days after surgery. Comprehensive Complication Index score includes minimum value of 0 and maximum value of 100; higher score means higher severity of complication(s).
Change in gut microbiome alpha and beta diversity after surgery according to pre-operative diet	Surgery date until 1 month after surgery	Metagenomic sequencing will be performed on stool samples collected in the first week after surgery and 30 days after surgery

Trial Locations

Locations (1)

Stanford Health Care; 🇺🇸 Stanford, California, United States