Objective: Since gut microbiota activity results in the production of specific microbial-derived metabolites (short-chain fatty acids) and structural components (LPS and peptidoglycans), changes in such microbiota composition appears to be involved in pathophysiology of common chronic disorders such as diabetes. Indeed, differences in gut microbiota between diabetic and nondiabetic subjects have been reported frequently in many ethnic groups, but not frequently in Japanese populations.

Research Design and Methods: Among participants of the population-based Iwaki study of Japanese held in 2016, those with information of gut microbiota evaluated using 16S rRNA sequencing were included in the study (gender (M/F): 446/672; age: 54.8±15.6). Diabetic (n=122): either on treatment for diabetes or HbA1c levels ≥6.5% or FBG ≥126 mg/dl; Nondiabetic (n=996): others.

Results: When examined the differences in gut microbiota in taxonomy category genus, proportions of several genuses were different between diabetic and nondiabetic subjects. Especially, proportions of the genus Streptococcus (4.79±9.53% vs. 2.12±3.74%, p=0.011) and Lactobacillus (3.11±8.10% vs. 0.344±1.95%, p <0.01), which are known to produce lactic acid, were higher, and genus Blautia (5.52±4.26% vs. 7.31±4.37%, p <0.01) and Bacteroides (8.14±9.38% vs. 10.8±7.84%, p <0.01), which are known to produce short chain fatty acids, were lower in diabetics subjects than those in nondiabetic subjects.

Conclusions: Differences in gut microbiota proportion were also found between diabetic and nondiabetic subjects in a Japanese population. Since lactic acid is known to have an effect of suppressing pathogenic bacteria, the increase in lactic acid producing bacteria may have effects against infection. Further, since short chain fatty acids act as signal transduction molecules that affect energy metabolism, the decrease in short-chain fatty acid producing bacteria may be involved in the development of diabetes.


M. Murabayashi: None. M. Daimon: None. H. Murakami: None. Y. Matsuhashi: None. A. Kamba: None. S. Mizushiri: None.

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