- Who is conducting this study?
- The Fiber Effectively Educates & Directs the Microbiome (FEEDMe) Study is led by Dr. Jennifer Smilowitz, PhD, at UC Davis. This study has been reviewed and approved by the UC Davis Institutional Review Board.
- What is the purpose of this study?
- The purpose of this study is to understand how commercially available foods made up of specific types of fiber influence the gut microbiome of healthy adults.
- Who can participate?
Healthy adults 18-50 years of age;
Adults with a body mass index (BMI) between 18.5 and 34.9 (click here to calculate your BMI);
Adults who consume at least 3 times (meals/snacks) per day;
Adults with normal stool frequency defined as 3 times per week to 3 times per day;
Adults willing to eat the study foods as part of their routine diet (includes multi-grain cereals, bread, pasta, snacks, canned beans, low-sodium lentil & pea soups, dried fruits, fruit purees, nuts & nut butters) for 18 days;
Adults willing to collect stool samples from on 3 different days;
Adults who live within a 40-mile radius from UC Davis campus (Davis) or UC Davis Medical Center (Sacramento).
- Who is NOT eligible to participate?
Pregnant or lactating individuals;
Current tobacco users (smoking, chewing or E-cigarettes);
Frequent cannabis users (more 4 times per week);
Users of illicit drugs (cocaine, crack, heroine, non-prescribed fentanyl etc.);
Users of restrictive diets (caloric restriction, intermittent fasting, keto-diet, gluten-free, grain-free, dairy-free, vegan);
Adults with food allergies or intolerances to milk, egg, wheat, beans; peanuts, tree nuts and seeds;
Users of fiber supplements or laxatives more than once per week;
History of gut surgery (appendectomy or hernia repairs are acceptable), or gall-bladder removal;
Adults with history of cancer, heart, liver, lung, endocrine, autoimmune, or kidney diseases; uncontrolled hyper- or hypothyroidism or hypertension; type 1 or type 2 diabetes; HIV; AIDS, hepatitis B or C; gut conditions (malabsorption disease, celiac disease, Crohn’s disease, colitis, inflammatory bowel disease, or irritable bowel syndrome;
Users of biologics, i.e., Lantus, Remicade, Rituxan, Humira, Herceptin, Avastin, Lucentis, Enbrel, for 2 weeks or longer and within the past 4 weeks.
- What is expected of me during the study?
- This study lasts 7 weeks long.
Participants will complete two online health and diet questionnaires that will take about 25 minutes to complete; eight 5-10-minute online weekly health questionnaires; six 24-hour dietary recall interviews; and daily stool logs for three weeks.
Participants will be asked to collect three stool samples using study-provided stool kits and to store the stool samples inside a sealable freezer box in their home freezer until a scheduled pick-up or transport time.
Participants will have four 60-90 min in-person visits (at UC Davis or their homes) and three short virtual visits with study personnel.
During the entire study period, participants will be asked to avoid eating fermented foods and beverages (yogurt, kefir, sauerkraut, etc.) or take probiotic, iron, and fiber supplements; laxatives and avoid changing their dietary supplement routine.
During the first two weeks and last two weeks of the study, participants will be asked to avoid eating foods that could interfere with the study results.
Click here to view the foods to avoid during the entire study and during the first and last two weeks of the study.
Participants will be asked to eat 4-5 study foods each day as part of their normal diet for 18 days and to fill out 65-80 online forms about the study foods they ate which will take about 1-2 minutes each to complete. Click here to view the study foods you will be asked to eat for 18 days. - Will I be compensated for participation?
- Participants will receive up to a $450 in electronic Target gift cards to complete the study activities.
