Читать книгу Clinical Obesity in Adults and Children - Группа авторов - Страница 61

The role of the gut microbiota in influencing obesity risk is much debated. The gut microbiome includes trillions of micro‐organisms that produce various metabolites, including short‐chain fatty acids and bile acids. Variation in microbiome composition could influence metabolism of the host and, therefore, potentially energy balance. This hypothesis is supported by studies in which the microbiomes of human twins discordant for obesity were transplanted into germ‐free mice. Those mice that obtained microbiota from the obese twin gained more fat mass than those that received the microbiota from the lean twin [117]. This finding is additionally supported by studies in mouse models in which transplantation of gut microbiota from an obese mouse donor to a germ‐free recipient results in a significant increase in body fat in the recipient [118]. Several investigators have seen higher BMI and rates of obesity among children or adolescents born by cesarean versus vaginal delivery [119]. One possible explanation for this difference is a different microbiome acquired by route of delivery, although alternatively, the effect may be explained by higher maternal BMI and child weight at birth. Evidence from animal husbandry as well as some human studies have demonstrated an association between antibiotic exposure during the first year of life and subsequent weight gain, risk of overweight, and central adiposity, which could suggest an association between the gut microbiome in early life and later obesity risk [120]. However, in large human studies, effect sizes for early‐life antibiotic exposure and later BMI are quite small [121] suggesting that such a mechanism is unlikely to be a major contributor to obesity rates in the population.