The aim of this study was to evaluate the effect of psychobiotic supplementation containing Lactobacillus helveticus R0052, Bifidobacterium bifidum R0071 and Bifidobacterium longum R0175 strains on mental health, quality of life, anthropometric measurements and some biochemical parameters in obese women. In the randomized double-blind placebo-controlled study, 28 obese female participants (14 psychobiotic, 14 placebo) will be given psychobiotic supplement/placebo together with a weight loss diet once a day every day for 4 weeks. Before and after the intervention, anthropometric measurements, blood samples and 24-hour retrospective 3-day food consumption records of the participants will be taken. In addition, the Depression Anxiety Stress Scale (DASS-21) will be administered to measure mental health, the SF-36 Quality of Life Scale to determine quality of life, and the International Physical Activity Questionnaire (IPAQ) to determine physical activity levels. Psychobiotics, which have entered our lives in recent years, have many beneficial effects on mental health through gut microbiota. However, while the effects of psychobiotics on mental health have been studied, their effects on obesity have not been investigated much. This study is unique in that it is the first study to investigate the effect of psychobiotic use on mental health in obese individuals. However, obesity is known to be an inflammatory disease and there is no study in the literature that includes the systemic immune inflammation index (SII) as a biomarker. SII is effective in evaluating the inflammatory and immune response in the body and determining prognosis; it adds value to clinical practice with early diagnosis of diseases, treatment follow-up and a wide range of uses.

Inclusion Criteria:

• Healthy adults aged ≥ 18-65 years
• BMI ≥30 kg/m2
• Willingness to volunteer
• Able to give written consent

Exclusion Criteria:

• Co-administration of probiotics. However, subjects will be eligible to participate after a four (4) week washout period.
• Pregnant or planning to become pregnant within the next two (2) months.
• Positive pregnancy test in women of childbearing potential.
• Use of antibiotic medication (e.g. neomycin, rifaximin) within the last 1 month. If this is the case, the participant will be eligible to participate four (4) weeks after completion of antibiotic treatment (washout period).
• Individuals with physician-diagnosed psychiatric and neurological conditions.
• Individuals with irritable bowel syndrome or gastrointestinal disorders.
• People with immune disorders or possible immunodeficiency states (e.g. due to surgery).
• Use of anti-inflammatory drugs
• Use of corticosteroids
• People who are allergic to milk, corn starch or soya.
• Foreign nationality.

Female