MicroFIBERgut: Effects of Lifestyle Changes and Chitosan on Gut Microbiota and Weight Management

The purpose of this study is to compare the effects of chitosan diet supplementation to a placebo supplement on changes in gut microbiota, body weight and different health parameters among different population groups, being either obese (BMI 30-50) and undertaking major changes in lifestyle (patients) or being those not undergoing any major lifestyle changes (volunteers, BMI 18.5-35).

The study will be conducted as a double-blind, block randomized, placebo-controlled intervention trial to study the effects of chitosan supplementation among two women population groups (Block 1- patients with obesity undergoing lifestyle changes; Block 2-women not undergoing major lifestyle changes) on their gut microbiota composition, body weight and composition among several other health parameters (blood pressure, blood lipids, blood sugar, insulin, hs-CRP, leptin). Furthermore, additional information will be collected: Health status, mental health, physical activity level, evaluation of stool appearance and defecation frequency by means of questionnaires; physical activity tracking, changes in body composition (muscle mass, body and visceral fat); evaluation of physical performance as well as adverse effects and remarks (diary book). The overall trial time for each subject will be 15 weeks: 1 week for baseline evaluation, 12 weeks intervention period and 2 weeks follow up.Collection of data will be done at 4 timepoints: at baseline, after 2 weeks of treatment, after 12 weeks of treatment and 2 weeks after the treatment ends (follow up).

Eligibility Criteria:
Inclusion Criteria:

Block 1

* Women, 18-80 years old with BMI \>30 kg/m2, maximal supine width 65 cm.
* Living in the proximity (about 60 km radius) of Reykjavik
* Ready to stop any intake of probiotics (i.e. Bio-Kult) and weight control supplement during the trial period (3.5 months)
* Undertaking major lifestyle changes (diet and physical exercise)
* Not planning pregnancy during the treatment period (3 months)

Block 2

* Women, 18-80 years old with BMI 18.5-35 kg/m2
* Living in the proximity (about 60 km radius) of Reykjavik
* Ready to stop any intake of probiotics (i.e. Bio-Kult) and weight control supplement during the trial period (3.5 months)
* Not undertaking any major changes in lifestyle
* Not planning pregnancy during the treatment period (3 months)

Exclusion Criteria:

* Eating disorders (i.e. anorexia, bulimia)
* Inflammatory bowel disease (e.g. Crohn's disease, ulcerative colitis)
* History of poorly controlled diabetes mellitus or hypertension
* Surgical procedures (abdominal and chest) or bariatric operation in the past 6 months
* History of invasive fat reduction procedure (e.g. liposuction or abdominoplasty) within the past one year
* Drug use: a) Drugs that can cause weight loss: SGLT2 inhibitors or GLP-1 analogs or other drugs simulating incretins in the digestive system for less than 3 months b) Warfarin
* Shellfish allergy
* Pregnant or breastfeeding
* Subjects taking or having taken diet pills or weight management supplements in past 30 days
* Use of antibiotics in the last 3 months