Small Bowel Microbiota Characterization in Healthy Individuals Before and After Consumption of a Western Diet

The gut microbiota is increasingly being implicated in disease. However, due to difficulty accessing the small bowel (i.e. requiring upper endoscopy) and the relative paucity of bacteria in this area (secondary to luminal flow and bactericidal bile acids/gastric acid), the small bowel microbiota is infrequently evaluated in any studies of this nature. The small bowel microbiota continues to remain an unexplored area of the gastrointestinal tract. Characterization of the microbial community and its function is the first step in determining how it potentially affects health and disease.

• Western diet (Behavioral): Western diet for 7 days: the meals in this Western diet will be provided by the Clinical Research and Trials Unit (CRTU) after participants meet with the nutrition staff (to discuss food preferences, how to obtain the meals). The meals will reflect a typical Western diet: a low fiber, high sugar diet with weight maintenance calories with < 10 grams fiber per day, and a typical US macronutrient calorie distribution of 50% carbs, 35% fat and 15% protein, with no alcohol. At least 50% of carbohydrates will be provided as simple sugars.

Primary outcomes

• Transcriptional changes in gut microbiota present in stool. [Baseline, approximately three weeks.]: DNA extraction from stool samples will be done using standard assays.

Sex: All, ages: 18 Years to 65 Years, accepts healthy volunteers

Inclusion Criteria:

* Adults between (and including) 18-65 years old.
* On a baseline healthy diet characterized by:

  * High fiber of ≥ 14 g/1000 calories/day
  * < 10% of daily calories from added sugar
  * At least 5 servings of fruit and vegetables per day
  * < or = 13% of daily calories from saturated fat

Exclusion Criteria:

* Patients who do not meet the above diet requirements.
* Known diagnosis of inflammatory bowel disease, microscopic colitis, celiac disease or other inflammatory conditions.
* Presence of abdominal symptoms based on baseline questionnaire.
* Commercial oral antibiotic or probiotic use within the past 4 weeks.
* Pregnancy or plans to become pregnant within the study time frame
* Vulnerable adults
* Any other disease(s), condition(s) or habit(s) that would interfere with completion of study, or in the judgment of the investigator would potentially interfere with compliance to this study or would adversely affect study outcomes.

• Purna C Kashyap, M.B.B.S., Principal investigator, Mayo Clinic