Obesity and insulin sensitivity: not everyone is equal!

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Researchers have recently shown that insulin sensitivity could be different in obese men and women, due to the composition of their intestinal microbiota.

We know that intestinal dysbiosis can lead to metabolic disorders, including a decrease in insulin sensitivity in non-diabetic obese subjects. In a new study, Dutch researchers wanted to see if this drop in insulin sensitivity was correlated to gender (male or female), as has already been shown for susceptibility to obesity and comorbidities related to dysbiosis. The researchers analyzed various biological factors: sensitivity to insulin (via a hyperinsulinemic-euglycemic clamp), body composition (rate and distribution of fat mass), substrate oxidation (indirect calorimetry), inflammatory markers, and the composition of the microbiota in overweight or obese men and women. They noted that the Bacteroidetes (B) / Firmicutes (F) ratio was higher in men than in women, and that it was inversely proportional to peripheral (and not hepatic) insulin sensitivity, but only in men. Changing the diet (adding fiber) had no effect on the microbial composition/insulin sensitivity association. Therefore, there is indeed a gender-based differentiation in metabolic responses in obese adults: women seem to be less sensitive to changes brought on by the composition of the microbiota. These observations, which need to be confirmed in a larger-scale study, should allow new therapeutic approaches to be developed for metabolic disorders related to obesity.

Source
Most J. et al. Gut microbiota composition strongly correlates to peripheral insulin sensitivity in obese men but not in women. Benef Microbes. 2017 Jun 16:1-6. https://www.ncbi.nlm.nih.gov/pubmed/28618864