This is a pilot study investigating how a novel probiotic supplement (BEO001), with and without a dietary fiber (beta-glucan), affects the lining of the small intestine in healthy people. The main goal is to see if a single dose of the probiotic changes gene activity (transcriptomics) and sugar molecule patterns (glycomics) in the gut. Eight participants will take three different treatments (placebo, probiotic alone, probiotic with fiber) in a random order, with at least 10 days between each. A gastroscopy to collect small intestinal tissue samples (biopsies) is performed the morning after each treatment. Blood and breath samples are also collected at these visits to explore effects on metabolism and inflammation. To understand how different sampling methods compare, participants collect stool samples and simple rectal swabs at home before any treatment. Researchers analyze the sugar molecules and bacteria in these samples, then compare them to each other and to the gut tissue samples collected after treatment. This helps determine if easier-to-collect samples can provide similar information to gut biopsies. The study also aims to combine all data (including genetics and diet) to identify key targets for future research and to attempt to grow 'mini-gut' organoids from the biopsies. The results will help design larger future studies in people with high uric acid levels.

Inclusion Criteria:

• Signed informed consent.
• Age 18-60 years.
• BMI 18.5 - 29.9 kg/m².
• Willing to avoid probiotics, fermented foods, and maintain stable diet/lifestyle for the study duration.

Exclusion Criteria:

• Chronic GI, inflammatory, metabolic (including renal), or significant psychiatric disease.
• Acute infection/allergy within 2 weeks.
• Regular use of NSAIDs, antibiotics, steroids, immunomodulators.
• Alcohol >9 units/week.
• Use of recreational drugs, tobacco, or nicotine.
• Known allergy to local anesthetics or sedatives for gastroscopy.
• Bleeding disorder or use of anticoagulants.
• Use of probiotics or antibiotics within 4 weeks prior.
• Pregnancy, breastfeeding, or planning pregnancy.
• Any condition deemed by investigator to compromise safety or data integrity

According to Swedish ethics regulations, IPD cannot be shared without an approved ethics application from the National Swedish Ethics Authority. An ethical permit can only be obtained for research being conducted within Sweden.