Alteration of gut microbiota by a Westernized lifestyle and its correlation with insulin resistance in non‐diabetic Japanese men

Abstract

Aims/IntroductionThe severity of insulin resistance is higher in Japanese‐American people with American lifestyles than in native Japanese people with Japanese lifestyles. Recently, the role of gut microbiota in the control of host metabolic homeostasis and organ physiology has been recognized. In addition, gut microbiota alterations have been suggested to contribute to pathogenesis of insulin resistance. The principle aim of the present study was to evaluate the impact of a Westernized lifestyle on the gut microbiota of Japanese‐Americans versus native Japanese, and its correlation with insulin resistance.Materials and MethodsA total of 14 native Japanese men living in Hiroshima, Japan, and 14 Japanese‐American men living in Los Angeles, USA, were included. A 75‐g oral glucose tolerance test was carried out for all participants to assess their glucose tolerance, and normal glucose tolerance was observed. We compared the insulin response with oral glucose load, the Matsuda Index, and the composition of the gut microbiota between the native Japanese and Japanese‐American men.ResultsJapanese‐American men showed higher area under the curve values for serum insulin concentrations during the oral glucose tolerance test and lower Matsuda Index than native Japanese men. Gut microbiota composition of the Japanese‐American men was different; in particular, they showed a relatively lower abundance of Odoribacter than native Japanese men. The ratio between relative abundance of Odoribacter and Matsuda Index was positively correlated between the two groups.ConclusionsOur findings suggest that Westernized lifestyles alter gut microbiota, and its alteration might induce insulin resistance in non‐diabetic Japanese men.

Baseline gut microbiome composition predicts metformin therapy short-term efficacy in newly diagnosed type 2 diabetes patients

“…More precisely, the microbiome of the Responders group at baseline was enriched with various taxonomic groups characterized as potentially probiotic. For example (1) Enterococcus faecium significantly decreased body weight, serum lipid levels, blood glucose level, and insulin resistance in rats fed with a high-fat diet [ 47 ]; (2) several Lactococcus lactis strains have shown the ability to reduce hyperglycemia, improve glucose tolerance and insulin secretion [ 48 , 49 ]; (3) bacteria from Odoribacter genus have been associated with a healthy fasting serum lipid profile [ 26 ], and displayed a negative correlation with insulin resistance [ 50 ]. The top result from this analysis–genus Dialister – has been characterized as a taxon possibly mediating the beneficial effects on the metabolic profile of whole-grains [ 51 ], however more data on underlying species are needed.…”

The Gut Microbiota and Its Implication in the Development of Atherosclerosis and Related Cardiovascular Diseases

“…Each person can present a wide variety of microorganisms in the gut depending on several things, like their lifestyle [52][53][54][55]. It is known that the microbiota varies widely during the first year of life, then it stabilizes as a consortium that resembles that of adults [56].…”

Incidental Prophylactic Appendectomy Is Associated with a Profound Microbial Dysbiosis in the Long-Term

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