Implementing Good Nutrition to Improve, Transform, and Enhance (IGNITE) Firefighters' Health (IGNITE FH)

Investigators hope to learn about potential dietary intervention strategies (specifically a whole-food, plant-based diet) that may help lower cancer markers in firefighters.

Study Overview

• Status: Completed
• Conditions: Inflammation; Cancer; Microbiome; Immune Function
• Intervention / Treatment: Behavioral: Whole Foods Plant-Based Diet; Behavioral: Usual Firehouse Diet

Detailed Description

The purpose of the San Francisco (SF) Firefighter's Diet Study is to determine if a diet low in processed foods, mostly plant-based, with added fermented foods, can lower the risk of cancer in firefighters. We will assess this by randomly assigning SF firefighters to either a whole-food, plant-based diet or their usual firehouse meals. Participants will be followed for 12 weeks.

• Study Type: Interventional
• Enrollment (Actual): 121
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Palo Alto, California, United States, 94305
      • Stanford University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age 18+
• Active SF firefighter
• Willing to consume a plant-based diet (vegetables, fruit, whole grains, legumes, etc.)
• Willing to complete 4 clinic visits

Exclusion Criteria:

• Weight < 110 lb
• BMI >= 40
• Self-reported uncontrolled hypercholesterolemia, hypertension or diabetes
• Pregnant, lactating, or planning to become pregnant during the course of the study.

• Use of any of the following drugs/supplements within the last 2 months:

  • systemic antibiotics, antifungals, antivirals, or antiparasitics (intravenous, intramuscular, or oral);
  • corticosteroids (intravenous, intramuscular, oral, nasal or inhaled);
  • cytokines;
  • methotrexate or immunosuppressive cytotoxic agents.
• Chronic, clinically significant, or unstable (unresolved, requiring ongoing changes to medical management or medication) pulmonary, cardiovascular, gastrointestinal, hepatic or renal functional abnormality, as determined by medical history, Type 1 diabetes, dialysis
• History of active cancer in the past 3 years except for squamous or basal cell carcinomas of the skin that have been medically managed by local excision
• Unstable dietary history as defined by major changes in diet during the previous month, where the subject has eliminated or significantly increased a major food group in the diet.
• Recent history of chronic excessive alcohol consumption defined as more than five 1.5-ounce servings of 80 proof distilled spirits, five 12-ounce servings of beer or five 5-ounce servings of wine per day; or > 14 drinks/week.
• Any confirmed or suspected condition/state of immunosuppression or immunodeficiency (primary or acquired) including HIV infection, multiple sclerosis, and Graves' disease.
• Surgery of the GI tract, with the exception of cholecystectomy and appendectomy, in the past five years. Any major bowel resection at any time.
• Regular/frequent use of smoking or chewing tobacco, e-cigarettes, cigars or other nicotine-containing products
• Regular use of prescription opiate pain medication

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Whole Food Plant-Based Diet; Participants will be asked to consume and predominantly vegan, whole-foods diet, with the addition of fish, eggs, and fermented dairy.	Behavioral: Whole Foods Plant-Based Diet; Whole foods, predominantly plant-based diet, with the addition of fish, eggs, and fermented dairy.
Active Comparator: Usual Firehouse Diet; Participants will be asked to consume their usual firehouse meals.	Behavioral: Usual Firehouse Diet; Usual firehouse meals.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in IL-6	Difference in the 8-week change from baseline in IL-6 between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in Glyc a	Difference in the 8-week change from baseline in Glyc a between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in C-Reactive Protein (CRP)	Difference in the 8-week change from baseline in C-Reactive Protein (CRP) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Interleukin-10 (L-10)	Difference in the 8-week change from baseline in Interleukin-10 (IL-10) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Tumor Necrosis Factor-alpha (TNF-alpha)	Difference in the 8-week change from baseline in Tumor Necrosis Factor-alpha (TNF-alpha) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Cytokines and Inflammatory Proteins	Difference in the 8-week change from baseline in a panel of cytokines and inflammatory proteins using the NUcleic acid Linked Immuno-Sandwich Assay (NULISA™) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Calprotectin	Difference in the 8-week change from baseline in Calprotectin between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in 8-hydroxy-2'-deoxyguanosine (8-OH-dG)	Difference in the 8-week change from baseline in 8-hydroxy-2'-deoxyguanosine (8-OH-dG) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Lipid Peroxidation	Difference in the 8-week change from baseline in Lipid Peroxidation between the whole-food plant-based vs. usual diet groups, using the Thiobarbituric acid-reactive substance (TBARS) assay.	Baseline and 8 weeks
Difference in Protein Carbonyl (protein oxidation)	Difference in the 8-week change from baseline in Protein Carbonyl (a measure of protein oxidation) between the whole-food plant-based vs. usual diet groups, using the enzyme-linked immunosorbent assay (ELISA).	Baseline and 8 weeks
Difference in Fasting Glucose	Difference in the 8-week change from baseline in Fasting Glucose between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Fasting Insulin	Difference in the 8-week change from baseline in Fasting Insulin between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Low-Density-Lipoprotein Cholesterol (LDL)	Difference in the 8-week change from baseline in Low-Density-Lipoprotein Cholesterol (LDL) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in High-Density-Lipoprotein Cholesterol (HDL)	Difference in the 8-week change from baseline in High-Density-Lipoprotein Cholesterol (HDL) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Triglycerides (TRGs)	Difference in the 8-week change from baseline in Triglycerides (TRGs) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Telomeres	Difference in the 8-week change from baseline in Telomeres between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in Epigenetic Age	Difference in the 8-week change from baseline in Epigenetic Age between the whole-food plant-based vs. usual diet groups, assessed by Epigenetic Clocks.	Baseline and 8 weeks
Difference in Gut Microbiome Composition	Difference in the 8-week change from baseline in Gut Microbiome Composition between the whole-food plant-based vs. usual diet groups, assessed by Metagenomic Sequencing.	Baseline and 8 weeks
Difference in Metabolomic Profiles	Difference in the 8-week change from baseline in Gut Microbiome Composition between the whole-food plant-based vs. usual diet groups, assessed by assessed by Targeted and Untargeted Metabolomics	Baseline and 8 weeks
Difference in 4-hydroxynonenal (HNE)	Difference in the 8-week change from baseline in 4-hydroxynonenal (HNE) between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in body composition	Difference in the 8-week change from baseline in body composition between the whole-food plant-based vs. usual diet groups, as assessed by dual energy x-ray absorptiometry scan (DEXA) scans.	Baseline and 8 weeks
Difference in weight	Difference in the 8-week change from baseline in weight between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in systolic blood pressure	Difference in the 8-week change from baseline in systolic blood pressure between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks
Difference in diastolic blood pressure	Difference in the 8-week change from baseline in diastolic blood pressure between the whole-food plant-based vs. usual diet groups.	Baseline and 8 weeks

Collaborators and Investigators

• Sponsor: Stanford University
• Investigators: Principal Investigator: Christopher D Gardner, PhD, Stanford University

Publications and helpful links

Helpful Links

• Study description and sign up

Study record dates

Study Major Dates

• Study Start (Actual): January 9, 2025
• Primary Completion (Actual): March 11, 2026
• Study Completion (Actual): March 11, 2026

Study Registration Dates

• First Submitted: August 20, 2024
• First Submitted That Met QC Criteria: August 20, 2024
• First Posted (Actual): August 22, 2024

Study Record Updates

• Last Update Posted (Actual): April 8, 2026
• Last Update Submitted That Met QC Criteria: April 2, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Inflammation; Cancer; Microbiome; Immune function
• Additional Relevant MeSH Terms: Pathologic Processes; Pathological Conditions, Signs and Symptoms; Neoplasms; Inflammation
• Other Study ID Numbers: IRB-75777; NCI-2025-01830 (Registry Identifier: National Cancer Institute Clinical Trials Reporting Program)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No