Fiber intervention to improve gut health and vaccine response

WHNRC (Western Human Nutrition Research Center) Fiber Intervention Study

This study tests if eating more fiber can help improve gut health and make the typhoid vaccine work better for people getting vaccinated.

Quick facts

• Phase: EARLY_PHASE1
• Study type: Interventional
• Enrollment: 60 (estimated)
• Ages: 18 Years to 59 Years
• Sex: All
• Sponsor: USDA, Western Human Nutrition Research Center (fed)
• Drugs / interventions: radiation, prednisone
• Locations: 1 site (Davis, California)
• Trial ID: NCT04543877 on ClinicalTrials.gov

What this trial studies

This study investigates the effects of dietary fiber, specifically inulin, on gut microbiota and immune responses to the Ty21a typhoid fever vaccine. Participants will consume either inulin or a maltodextrin control for three weeks before, during, and after vaccination. The study aims to assess changes in gut bacteria, inflammation levels, gut permeability, and immune responses by measuring specific immune markers. The goal is to determine if increasing dietary fiber can enhance vaccine efficacy and gut health.

Who should consider this trial

Good fit: Ideal candidates are healthy adults aged 18 and older with a BMI between 18.5 and 30.9 and inadequate dietary fiber intake.

Not a fit: Patients with immune system disorders, certain cancers, or those who are pregnant or lactating may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved vaccine responses and better gut health for individuals with low dietary fiber intake.

How similar studies have performed: Other studies have shown promising results in enhancing gut health and immune responses through dietary interventions, suggesting this approach may be effective.

Eligibility criteria

Inclusion Criteria:

1. Body Mass Index (BMI) 18.5 - 30.9 kg/m2
2. inadequate total dietary fiber intake defined as:

   * Females 18 - 30 years old, less than 28 g/day
   * Females 31 - 50 years old, less than 25 g/day
   * Females 51+ year old, less than 22 g/day
   * Males 18 - 30 years old, less than 34 g/day
   * Males 31 - 50 years old, less than 31 g/day
   * Males 51+ years old, less than 28 g/day

Exclusion Criteria:

1. blood pressure greater than or equal to 140/90 mmHg
2. has HIV/AIDS or another disease that affects the immune system
3. has any kind of cancer
4. inability to lift 30 pounds with assistance (for transporting refrigerated stool containers)
5. decline to take an HIV blood test
6. pregnant or lactating women
7. refusal to take a pregnancy test
8. female subjects: refusal to use a method of birth control 1 week prior to the administration of the vaccine, 1 week during the vaccine, and 1 week after the vaccine
9. allergy to vaccine components, i.e. thimerosal and enteric-coated capsules
10. allergy to oral typhoid vaccine
11. use of anti-inflammatory medications, i.e. nonsteroidal anti-inflammatory drugs (NSAID), aspirin, 3 or more times per month
12. use of sulfonamides or antibiotics 3 months prior to the receipt of Ty21a vaccine.
13. use of anti-hypertensive drugs, i.e. beta blockers, diuretics, calcium channel blockers
14. use of anti-malaria drugs, i.e. mefloquine, chloroquine, and proguanil
15. use of drugs that affects the immune system, i.e. immunosuppressants, immune-modifying drugs, corticosteroids, i.e. cortisone, prednisone, methylprednisolone, for 2 weeks or longer
16. use of biologics, i.e. Lantus, Remicade, Rituxan, Humira, Herceptin, Avastin, Lucentis, Enbrel for 2 weeks or longer
17. undergoing cancer treatment with radiation or drugs
18. greater than 10 years residence in a typhoid-endemic area
19. receipt of typhoid vaccine in the last 5 years
20. receipt of any vaccine two weeks prior to receipt of Ty21a vaccine
21. individuals at increased risk of developing complications from a live, bacterial vaccine
22. history of typhoid fever
23. history of primary immune deficiency or autoimmune disease
24. history of acute or chronic gastrointestinal (GI) disorder, i.e. Crohn's disease, irritable bowel syndrome, gastric ulcer
25. diarrheal illness (defined as passing 3 or more abnormally loose or watery stool in a 24 hour period) or persistent vomiting 2 weeks prior to the study
26. history of chronic illnesses, i.e. diabetes, cardiovascular disease, cancer, gastrointestinal malabsorption or inflammatory diseases, kidney disease, autoimmune disorders, HIV, liver disease, including hepatitis B and C
27. asthma if taking medication on a daily basis
28. recent surgery (within 3 months)
29. history of GI surgery
30. recent hospitalization (within 3 months)
31. fever (within 2 weeks)
32. unwillingness to discontinue probiotic, prebiotic, or other supplements (except Recommended Dietary Allowance-level vitamin and mineral supplements), fiber supplements, or food and beverage products containing inulin, chicory root fiber, or maltodextrin during the study
33. not having at least one arm vein suitable for blood drawing
34. unwilling or uncomfortable with blood draws and stool collections
35. regular blood or blood product donation and refusal to suspend donation
36. current participation in another research study
37. unable to fast for 12-16 hours
38. have fewer than 3 bowel movements per week
39. consuming one or more servings of added-inulin foods per day over the past month

Where this trial is running

Davis, California

• USDA, ARS, Western Human Nutrition Research Center — Davis, California, United States (RECRUITING)

Study contacts

• Principal investigator: Danielle Lemay, PhD — USDA, ARS, Western Human Nutrition Research Center
• Study coordinator: Ellen Bonnel, PhD

Conditions: Inflammation, Vaccine, Intestinal Permeability, Typhoid Fever, Gastrointestinal Health, Vaccine Response, Ty21a Typhoid Vaccine, Microbiome