Effect of Probiotics on Appetite Regulation in Adults With Overweight/Obesity

Rationale: Satiety hormones, including glucagon-like peptide-1 (GLP-1), are key regulators of food intake. Deficiencies in the release of satiety hormones as well as alterations in the composition and the function of the gut microbiota are hallmarks of overweight and obesity. Probiotics can improve the overall structure of the gut microbiota, and show strain-specific differences with regard to their ability to stimulate satiety hormones. Those animal-based findings, if confirmed in human studies, may pose a gateway for decreased food intake, weight management, and ultimately weight loss. The investigators hypothesise that a newly developed combination of probiotic strains, specifically selected for their potential to (in vitro) influence pathways related to weight management, will decrease food intake through increased release of satiety hormones (i.e. GLP-1) and beneficial alteration of the gut microbiota in humans.

Objective: The primary objective of the study is to investigate the effects of a combination of specifically selected probiotic strains in a new probiotic formulation on ad libitum food intake, in individuals with overweight and/or obesity. The investigators will address this objective firstly with an acute study followed by a proof-of-concept 4-months intervention study comparing a total of 98 individuals in a 16-week randomised, placebo-controlled parallel study (49 participants probiotic/ 49 participants placebo).

Study design: This intervention study will have a randomised, controlled parallel design. The total study duration will be 16 weeks.

Study population: A total of 98 men and women between the ages of 20-70 years old, with overweight/obesity (BMI: 26-40 kg/m2) will be recruited, accounting for a drop-out rate of 20%.

Intervention: Study participants will receive a daily dose of 6 g probiotic supplement (packed in sachets of 3 g) or placebo for 16 weeks.

Main study parameters/endpoints: At baseline and after 16 weeks, participants will visit the research facilities for assessments. The primary endpoint is the difference in satiety measured by ad libitum food intake comparing the probiotic and control intervention. Secondary outcome parameters are related to changes in satiety hormones (including GLP-1), fecal microbiota analysis, insulin sensitivity (HOMA-IR), inflammatory markers and lipid metabolism.

Exploratory outcomes concern perceived satiety, body composition and mental health. This study will provide insight into the potential beneficial effect of a newly composed probiotic supplement on satiety in overweight/obese adults.

Inclusion criteria

• Men and women, aged between 20-70 years
• BMI ³ 25 kg/m2
• Stable body weight (weight gain or loss < 3 kg in the past three months)
• Willingness to give up being a blood donor from 8 weeks before the start of the study, during the study and for 4 weeks after completion of the study
• No difficult venipuncture as evidenced during the screening visit

Exclusion criteria

• Diabetic patients (type 1 and type 2)
• Abuse of drugs
• More than 2 units alcoholic consumptions per day for women and 3 for men
• Use of products or dietary supplements known to interfere with the main outcomes 3 months prior to the start of the study as judged by the principal investigators
• Gastrointestinal disease (including IBD and IBS)
• Use of an investigational product within another biomedical intervention trial within the previous 1-month
• Severe medical conditions that might interfere with the study, such as epilepsy, asthma, kidney failure or renal insufficiency, chronic obstructive pulmonary disease, autoimmune disease and rheumatoid arthritis
• Active cardiovascular disease like congestive heart failure or cardiovascular event, such as an acute myocardial infarction or cerebrovascular accident
• use of lipid- and glucose lowering medication, corticosteroid use
• Psychiatric diagnoses including clinical depression
• Intolerances or dietary habits that might interfere with the study (i.e. lactose intolerance or veganism)
• pregnancy
• smoking, vaping
• use of antibiotics up to 3 months prior to the study