Functional Research of Emulsifiers in Humans

This is a randomized double-blind, controlled feeding experiment examining the effect of CMC
on the stool microbiota composition, gene expression, and microbiota localization with
respect to the epithelium. In addition, the investigators will assess the impact of CMC
exposure in the diet on markers of metabolic syndrome including response to oral glucose
tolerance testing and other plasma metabolite measurements.

Sixteen healthy volunteers will be recruited for a 11-day in-patient study. All participants
will receive 3 full days of freshly prepared emulsifier-free food to begin the study. This
will be called the "washout period". Participants will then be randomized into an
"emulsifier-free" arm and a "CMC" arm in a 1:1 ratio.

Both arms will continue the same diet except that the "CMC" arm's brownie and sorbet will
have CMC added to achieve a level of 15 gm per person per day consumption. Serial collection
of fecal, plasma, urine and mucosal biopsy samples will be performed to investigate the
extent to which CMC consumption by humans impacts the gut microbiota and its interaction with
the host parameters related to inflammation and metabolism. Participants will have daily
urine and stool collections. Sigmoidoscopies and glucose tolerance testing will be completed
on day 1and 11. Blood samples are collected on days 1-4, 8, 10, and 11.

Inclusion Criteria:

1. Participant is capable of giving informed consent

2. Participant is age 18 to 60 years

Exclusion Criteria:

1. Diagnosis with 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.

2. 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.

3. 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.

4. Body Mass Index (BMI) <18.5 or >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.

5. 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

6. 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).

7. 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.

8. 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 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 INR greater than 1.2 will be excluded from the study.

9. Estimated GFR<60ml/min/1.73m2 based on measured serum creatinine concentration

10. 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.

11. 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

12. 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
milieu or by altering fecal transit time. For our study purposes, multivitamins will
not be considered dietary supplements.

13. Use of laxatives or anti-diarrhea medications in the two weeks prior to Visit 2.

14. Use of anticholinergics in the week prior Visit 2.

15. Use of narcotics in the week prior to Visit 2.

16. HIV infection, AIDS, or other known conditions resulting in immunosuppression - we
will determine this by direct participant query; no formal testing will be done.

17. Allergies or intolerance to the components of the study diets.

18. Participant has experienced diarrhea within the two weeks prior to Visit 2. Diarrhea
is defined as a change in bowel habits with an increased frequency or loose stools
such that the stool could not be lifted with a fork.

19. Refusal to use a medically accepted method of birth control while participating in
this study, such as a barrier method, hormonal contraceptives, implanted birth control
devices, permanent methods (such as a vasectomy), and/or abstinence.

20. Vegans and Vegetarians.

21. Student or employee of any one of the investigators.

22. Anyone who cannot receive study payment (ie: visa)

23. Any condition that the investigator feels may limit the volunteer's ability to
complete the study protocol.