Changes in the Composition and Diversity of the Intestinal Microbiota Associated with Carbohydrate Consumption in Type 2 Diabetes Mellitus Patients

Type 2 diabetes <i>mellitus</i> (T2DM) is a multifactorial disease, influenced by dietary and environmental factors that can modify the intestinal microbiota. The aim of this study was to evaluate changes in the composition and diversity of the intestinal microbiota associated with carbohydrate (CHO) consumption in T2DM patients. Forty patients participated, with and without T2DM. Fecal samples were collected for the characterization of microbial diversity from the massive sequencing of the 16S rRNA gene. Carbohydrate consumption was quantified using the Frequency Consumption Foods questionnaire (FCF), the groups were categorized according to Body Mass Index (BMI) and BMI + CHO consumption. The group without T2DM showed normal biochemical and anthropometric parameters, although they had a high carbohydrate consumption compared to the group with T2DM. At the <i>phylum</i> level, there were differences in relative abundance; the control overweight group (CL-OW > CHO) and T2DM-Normal Weight > CHO patients had increased <i>Bacteroides</i> and decreased <i>Firmicutes</i>. In contrast, the CL-OW > CHO and T2DM-OW < CHO patients, showed reduced <i>Bacteroidetes</i> and an elevated amount of <i>Firmicutes</i>. At the genus level, the differences were in the relative abundance of <i>Roseburia</i>, <i>Clostridium_IV</i>, <i>Prevotella</i>, and <i>Sporobacter</i>, associated with the consumption of carbohydrates. The groups that consumed high amounts of carbohydrates, regardless of whether they had diabetes <i>mellitus</i> or were overweight, had a significantly reduced proportion of <i>Faecalibacterium</i>, an altered proportion of <i>Bacteroides</i>. The high consumption of carbohydrates showed considerable modifications in the composition and diversity of the bacterial communities.