This study evaluates whether a fruit- and vegetable-based fermented product (Rutazyme® lemon fermented product) taken as a capsule can improve metabolic health in adults with obesity. Forty adults aged 18-65 years with obesity (BMI ≥ 27 kg/m² and waist circumference > 90 cm for men or > 80 cm for women) will be randomly assigned to receive either a Rutazyme® lemon fermented product capsule (500 mg) or a placebo capsule once daily at bedtime for 12 weeks. Before supplementation, participants will complete a 2-week stabilization period during which they maintain their usual diet and physical activity.

Body composition and waist/hip measurements will be assessed during the study, and blood pressure will be monitored. Blood samples will be collected to evaluate metabolic and safety laboratory measures (e.g., lipids, glucose, insulin, inflammation markers, liver and kidney function), and stool samples will be collected to assess gut microbiota. Gut-brain axis biomarkers (GLP-1 and PYY) will be measured at multiple time points after capsule intake at baseline and at Week 12. The results will help determine the metabolic effects and safety of Rutazyme® lemon fermented product supplementation in adults with obesity.

This is a randomized, placebo-controlled, parallel-group study designed to assess the metabolic effects and safety of Rutazyme® lemon fermented product capsules in adults with obesity. A total of 40 participants (18-65 years) with simple obesity (BMI ≥ 27 kg/m²; waist circumference > 90 cm for men or > 80 cm for women) will be enrolled and randomly assigned in a 1:1 ratio to one of two arms: (A) placebo capsule or (B) Rutazyme® lemon fermented product capsule (500 mg). Participants will undergo a 2-week stabilization period prior to supplementation (Week -2 to Week 0) and will be instructed to maintain their usual diet and physical activity habits throughout the study. The intervention period lasts 12 weeks, during which participants will take one capsule orally once daily at bedtime with water.

Assessments are scheduled at Week -2 (stabilization), Week 0 (baseline), and Weeks 4, 8, and 12. Measures include body composition (InBody 570), waist and hip circumference, blood pressure and heart rate, and assessments of dietary intake and physical activity (including estimation of total daily energy expenditure). Safety and metabolic laboratory assessments include complete blood count; lipid profile (TG, TC, LDL-C, HDL-C); fasting glucose and insulin; inflammatory marker (hs-CRP); liver function (AST/GOT, ALT/GPT, γ-GT, albumin); and renal function (BUN, creatinine, uric acid). Stool samples will be collected at baseline and Week 12 for gut microbiota analysis.

To explore mechanistic gut-brain axis biomarkers, GLP-1 and PYY will be assessed at baseline and at Week 12 at multiple time points (0, 30, 60, and 120 minutes) following capsule intake. Blood samples will be collected by trained personnel, with procedures designed to minimize discomfort (e.g., use of an indwelling catheter during repeated time-point sampling). Laboratory analyses will be performed by qualified external laboratories.

Inclusion Criteria:

• Age 18 to 65 years.
• Body mass index (BMI) ≥ 27 kg/m².
• Waist circumference > 90 cm for men or > 80 cm for women.
• Able and willing to provide written informed consent and comply with study procedures.

Exclusion Criteria:

• Pregnant, breastfeeding, or menopausal or postmenopausal.
• Use of enzyme supplements or fiber supplements within the past month.
• Current treatment with antihypertensive medications.
• Gastrointestinal disorders, including inflammatory bowel disease (e.g., ulcerative colitis or Crohn's disease).
• Major cardiovascular, metabolic, or renal disease.
• Unable to provide informed consent or insufficient decision-making capacity.
• Investigator determines the participant is not suitable for the study.

Participants and investigators are blinded to treatment assignment. Rutazyme® and placebo capsules are identical in appearance and packaging.