Following the Mediterranean Diet improves intestinal microbiota (commonly called intestinal flora) and allows for better metabolic control in patients with type 2 diabetes, indicates a study conducted by researchers from CINTESIS – Center for Health Technologies and Services Research and the NOVA Medical School – Faculty of Medical Sciences, under the coordination of Conceição Calhau.

The results of the study “MEDBIOME – Effect of the Mediterranean Diet on the Microbiome of Type 2 Diabetics”, published in the journal Nutrients, show that diabetics who follow this dietary pattern have a richer intestinal microbiota, with a greater number of bacterial species, which in turn translates into better glycemic control, i.e. blood sugar levels.

The Mediterranean Diet is characterized by high consumption of plant-based products (vegetables, fruit, whole grains and fatty fruits), low to moderate meat consumption, use of herbs and spices instead of salt, and use of olive oil as the main source of fat. This eating pattern favors seasonal and local foods and encourages other healthy habits, such as physical activity.

As part of this study, the researchers followed people with type 2 diabetes, aged from 47 to 77 years, over the course of 12 weeks. An individualized diet plan based on the Mediterranean Diet was implemented and several parameters were analyzed, including gut microbiota composition, weight, and glycemic control.

The main goal was to evaluate the role of microbiota modulation in type 2 diabetics, through the implementation of a nutritional intervention based on a dietary pattern that is already recommended in the treatment of this disease.

The analysis points to increased richness and quality of gut bacteria (higher Prevotella/Bacteroides ratio and lower Firmicutes/Bacteroidetes ratio) after only four weeks and better glycemic control among participants after 12 weeks as a result of increased adherence to the Mediterranean Diet.

According to the team, “the change in gut microbiota appears to precede the change in markers of diabetes,” particularly glycated hemoglobin (HbA1c), an indicator of blood glucose levels.

In this sense, “the composition of the intestinal microbiota may be used as a new biomarker of the effectiveness of the nutritional intervention adopted and of diabetes control,” says Cláudia Marques, CINTESIS researcher, professor at the NOVA Medical School and co-founder of YourBiome.

On the contrary, “a poor gut microbiota” may alert to the ineffectiveness of the chosen nutritional intervention, allowing the strategy to be redefined, more quickly and efficiently.

Thus, this study reinforces the importance of nutritional intervention and, in particular, the Mediterranean Diet, in the control of diabetes, highlighting the decisive role of nutritional support given to diabetic patients, particularly those followed in Primary Health Care (PHC).

“The results of this work allow us to conclude not only that the analysis of the gut microbiota may be useful in monitoring the disease, but also that the gut microbiota is an important therapeutic target in diabetes, i.e., that the treatment of diabetes may involve improving the type of bacteria we have in our gut,” summarize the researchers.

The article, authored by Shámila Ismael, Marta Silvestre, João Araújo, Diogo Pestana, Ana Faria, Diana Teixeira, Cláudia Marques and Conceição Calhau, from CINTESIS/NOVA Medical School – Faculty of Medical Sciences, among other researchers, results from a project awarded, in 2019, with a grant of the Portuguese Society of Diabetology (SPD).