Introduction: The
Mediterranean Diet (MD) is useful in the prevention of
overweight,
obesity and
metabolic disease. High Quality-Extra Virgin
Olive Oil (HQ-EVOO), an essential component of this diet, exerts protective effects against
chronic diseases. Gut Microbiota (GM), recognized as a key factor in driving metabolic activities, is involved in the regulation of host immunity. Lactic Acid Bacteria (LAB) and their probio-active cellular substances produce beneficial effects in the gastrointestinal tract. Materials and Methods: Eighteen
overweight/obese subjects (cases, BMI ≥25 kg/m2) and 18 normal weight controls (BMI 18.5-24.9 kg/m2) were fed with MD enriched with 40 g/die HQ-EVOO for three months. Feces and blood samples were collected at time 0 (T0) and after three months (T1) for LAB composition, oxidative stress, metabolic and
inflammation parameter determinations. Results:
Myeloperoxidase and 8-hydroxy-2-deoxyguanosine, markers of
inflammation and oxidative stress, were significantly decreased after MD rich in HQ-EVOO both in controls and in cases. Proinflammatory
cytokines levels were significantly decreased in cases in comparison to controls, while
IL-10 and
adiponectin were significantly increased in cases. LAB's rpoB copies/ng of
DNA increased 55.6 folds in cases compared to their baseline after MD rich in HQ-EVOO. MD rich in HQ-EVOO increased
adiponectin and
IL-10 concentration in
overweight/obese subjects and decreased oxidative stress and
inflammation parameters and at the same time, increased LAB number in GM. Discussion: Our results indicate that MD rich in HQ-EVOO induces an increase of LAB in GM and could have a potential role in the prevention of
inflammation. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT03441802.