The purpose of this clinical trial was to evaluate the effects Lactococcus cremoris spp. im-mobilized on oat flakes on human microbiome and blood and urine biomarkers of associated with human health.

All eligible and consenting individuals were assigned a unique code for identification purposes. They were then randomly assigned to either the probiotic or placebo group. The probiotic group received oat flakes containing immobilized Lactococcus cremoris, while the placebo group received oat flakes indistinguishable in color, smell, and taste from the flakes with immobilized probiotics.Participants received written instructions on storing the product, which required refrigeration. They were instructed to consume 5 g of oats daily with a meal, ensuring the meal's temperature remained below 35 °C and was non-acidic (e.g., with yogurt). Biological samples were collected at three time points; before intervention, at 6th and 12th week.

Inclusion Criteria:

• participants to be aged between 18 and 65 years
• clinically tested with fasting plasma glucose less than 100 mg/dL
• clinically tested withcholesterol less than 220 mg/dL
• otherwise healthy

Exclusion Criteria:

• body mass index [BMI] higher than 40 kg/m2 (morbidly obese)
• following a diet plan for weight loss
• following a contraceptive treatment or taking probiotic supplements
• following medication with an effect on lipaemia or glycemia indicators
• having any allergies/intolerances to trial ingredients
• pregnant or planning to become pregnant or breast feeding
• users of illicit drug, having a chronic alcoholism or total daily alcohol intake more than 50 g per day
• diagnosed with a chronic condition (cancer, active liver disease, severe kidney dysfunction, severe stroke in the last six months and conditions associated with an increased risk of bleeding) or any other serious medical condition that may affect the individual's ability to participate in a dietary intervention study
• considered unreliable by the researcher or having a shorter life expectancy than the expected duration of the study due to some illness or if they were in any situation in which by the researcher's opinion their participation in the study was not considered safe (e.g. drug addiction, alcohol abuse).