**6. Diet and the microbiota**

The importance of microbiota in the incidence of diabetes has been a recently discussed development. The gut microbiota has been hypothesized to be a link between environmental factors and the development of autoimmunity and diabetes [31]. The first gut microbiota composition is mostly acquired at birth, while the delivery mode determines the type of microorganisms that will colonize the newborn gut. After delivery, the diet is one of the main factors affecting the composition of infant gut microbiota. The diet provides substrates and sources of bacterial contamination from breast and nipple skin to breastfed babies [31]. Diet also contributes indirectly toward the regulation of intestinal and pancreatic health.

In several studies, it was found that the age, dietary patterns, geography, traditions, and culture were the main determinants explaining the differences in gut microbiota composition [31–33]. The modulation of the immune system by the gut microbiota essentially begins even before birth. It is obvious that the intrauterine environment of the fetus during pregnancy is not completely sterile. There is evidence that the placenta of a term pregnancy has many nonpathogenic commensal microbiota in low-abundance, similar to the oral microbiome of nonpregnant women [31]. Following birth, diet, and microbiota are the decisive factors that guide the proper maturation of the immune system [32].

Dietary antigens, especially those associated with type 1 diabetes, depend on early feeding regimens, the age of introduction of foods, especially wheat, to the infant's diet, and the current consumption of nutrients [34, 35]. Understanding and hypothesizing that the gut microbiota is an organ will make it possible to integrate its relationship with diabetes as a key for designing new therapies to prevent and/or improve the control and propagation of the disease. Dietary components provide different substrates, which may ultimately result in several products during the fermentation processes. Changes in the structure of the microbiota due to dietary modifications are because some of the bacterial communities are "genetically better equipped" to metabolize those substrates [31].
