Functional Research of Emulsifiers in Humans

Inclusion Criteria

• Participant is capable of giving informed consent
• Participant is age 18 to 60 years

Exclusion Criteria

• Diagnosis with Inflammatory Bowel Disease (IBD), celiac disease, or other chronic intestinal disorders. Since we are interested in assessing the impact of diet on the microbiome in the absence of pathologic inflammation, we will exclude participants with chronic intestinal abnormalities.
• Baseline bowel frequency less than every 2 days or greater than 3 times daily. Normal bowel frequency is every 3rd day to 3 times per day.20-23 Although unknown, stool frequency could be related to the microbiome composition.24-26 Furthermore, change in diet could alter baseline stool frequency, potentially causing diarrhea, particularly in those with high baseline stool frequency, or severe constipation in those with low stool frequency. To avoid the need for use of antidiarrheal medications or laxatives, which themselves could alter the microbiome composition, these patients will be excluded.
• Current smoker. What effect smoking has on the microbiome of the gut is unknown. Furthermore, because our hospital is a smoke-free environment, volunteers will not be able to smoke. Thus, inclusion of smokers would increase the risk of early withdrawal from the study.
• Body Mass Index (BMI) 40 at screening. Volunteers with BMI below normal27 will be excluded to prevent inclusion of participants with a subclinical systemic disease that may influence the gut microbiome. Volunteers with severe obesity will be excluded as obesity may be associated with altered gut microbiome composition.
• More than two of the criteria for metabolic syndrome:
• A waist circumference greater than 35 inches (89 centimeters) for women and 40 inches (102 centimeters) for men at screening.
• A diagnosis of diabetes mellitus or baseline HbA1c > 6.4% or a fasting glucose level of greater than 100mg/dL
• Systolic blood pressure >130 mmHg or diastolic blood pressure >85 mmHg or treated with medications for hypertension at screening.
• Fasting triglycerides >149 mg/dl or treated with medications for hypertriglyceridemia
• Fasting HDL cholesterol <40 mg/dl in men or <50 mg/dl in women or treated with medications for hypercholesterolemia
• Known substance abuse disorder or consumption of illicit drugs or alcohol in the 24 hours prior to admission to the Center for Human Phenomic Science (CHPS).
• Prior bowel resection surgery other than appendectomy. It is unknown how prior bowel resection surgery may influence the microbiome composition, hence we will exclude these participants.
• Contraindication to flexible sigmoidoscopy and biopsies. Patients with suppressed white blood count may be at increased risk of systemic infection following sigmoidoscopy with biopsies. As such, participants with a white blood cell (WBC) less than 3,500 or an absolute neutrophil count of less than 1,000 will be excluded. Patients with thrombocytopenia or with a coagulopathy may be at increased risk of bleeding complications after colonoscopic biopsies. As such, patients with a platelet count of less than 100,000 or an international normalized ratio (INR) greater than 1.2 will be excluded from the study.
• Estimated glomerular filtration rate (GFR)<60ml/min/1.73m2 based on measured serum creatinine concentration
• Pregnant and lactating women. To avoid any risk to an unborn fetus or new born baby from changing the mother's diet, pregnant and lactating women will be excluded.
• Use of antibiotics in the 6 months prior to Visit 2. A small proportion of bacteria may require 6 months to recover after treatment with antibiotics.28
• Use of antacids, NSAIDs, or dietary supplements in the week prior to Visit 2. NSAIDs have been associated with C. difficile colitis, although whether this is causative and whether this is mediated through changing the fecal microbiota composition is unknown.29 Antacids could potentially alter the gut microbiota by changing the acid