Dysbiosis of gut microbiota is associated with the pathophysiology of type 2 diabetes. Mediterranean diet has been indicated as a dietary pattern that promote the integrity of gut barrier and that has positive impact in the metabolic control of subjects with type 2 diabetes. This is a 12-week, single-arm clinical study that aims to evaluate if the effect of Mediterranean diet in metabolic control of these subjects is mediated by gut microbiota. Subjects will receive personalized nutrition counseling where Mediterranean diet will be promoted.

Inclusion Criteria:

• Men and women diagnosed with type 2 diabetes mellitus, according to the American Diabetes Association criteria;
• Ages 40-80 years;
• Non-smoker;
• Willing and able to provide written informed consent.

Exclusion Criteria:

• Diabetes diagnosed before 40 years old;
• Changes in oral glycaemic-control medications in the last 3 months;
• Subjects with HbA1c levels under 6.4% or above 10%;
• Subjects under insulinotherapy;
• Subjects under corticotherapy;
• Subjects with triglycerides levels above 4.52 nmol/L (400 mg/dL);
• Intake of antibiotics in the last 12 weeks;
• Subjects with a diagnosis of any digestive disease including functional bowel disorders such as IBS.