Microbiogeographic insights as keys to understanding personalized gut microbiota responses: the role of <i>Bifidobacterium</i> residing on intestinal starch granules

There is growing optimism regarding the potential therapeutic and preventive benefits of regulating intestinal microbiota for various diseases. Diet is one of the most straightforward and safest methods for modulating the intestinal microbiota; however, considerable individual differences have been observed in the microbiota response to dietary interventions. These individual differences pose substantial challenges in application, which are primarily attributed to variations in the commensal flora and bacterial competition for nutrients. Our previous research indicated that the microscopic localization of bacteria provides valuable insights into the mechanisms by which specific intestinal bacterial species acquire nutrients within a competitive gut environment. Furthermore, our analysis revealed that the combination of bifidobacterial species and the nutrient source found in the localization analysis determined individual differences in microbiota response. These findings suggest that bacterial colonization facilitates the efficient, preferential, and presumably exclusive utilization of solid nutrient sources in the human gut. Moreover, the impact of a single nutrient source on the gut and human body may vary depending on the presence or absence of the primary species colonizing that source. In this review, we examined the micrometer-scale localization of intestinal bacteria and individual variability in microbiota responses to diet, drawing upon the results of our previous studies.