Stool energy density is positively correlated to intestinal transit time and related to microbial enterotypes

Abstract

Background It has been hypothesised that the gut microbiota causally affects obesity via its capacity to extract energy from the diet. Yet, evidence elucidating the role of particular human microbial community structures and determinants of microbiota-dependent energy harvest is lacking. Results Here, we investigated whether energy extraction from the diet in 85 overweight adults, estimated by dry stool energy density, was associated with intestinal transit time and variations in microbial community diversity and overall structure stratified as enterotypes. We hypothesised that a slower intestinal transit would allow for more energy extraction. However, opposite of what we expected, the stool energy density was positively associated with intestinal transit time. Stratifications into enterotypes showed that individuals with a Bacteroides enterotype (B-type) had significantly lower stool energy density, shorter intestinal transit times, and lower alpha-diversity compared to individuals with a Ruminococcaceae enterotype (R-type). The Prevotella (P-type) individuals appeared in between the B- and R-type. The differences in stool energy density between enterotypes were not explained by differences in habitual diet, intake of dietary fibre or faecal bacterial cell counts. However, the R-type individuals showed higher urinary and faecal levels of microbial-derived proteolytic metabolites compared to the B-type, suggesting increased colonic proteolysis in the R-type individuals. This could imply a less effective colonic energy extraction in the R-type individuals compared to the B-type individuals. Notably, the R-type had significantly lower body weight compared to the B-type. Conclusions Our findings suggest that gut microbial energy harvest is diversified among individuals by intestinal transit time and associated gut microbiome ecosystem variations. A better understanding of these associations could support the development of personalised nutrition and improved weight-loss strategies.

Intermittent fasting modulates the intestinal microbiota and improves obesity and host energy metabolism

“…Furthermore, gut transit time was not measured in this study. Since previous studies have reported that the gut transit time influences the composition of the gut microbiota [37][38][39] , interactions between IF and the gut microbiota may be modulated by this factor. Finally, experiments to investigate and validate the mechanisms linking IF, gut microbiota, and host metabolism were not performed in this study.…”

Investigating the Rescue Potential of Fecal Microbiota Transplants in Anorexia Nervosa using Antibiotic-treated Mice in a Split Group Cross-Over Study

“…by simply moving less (26), and the differences only becomes clear if using calorie restriction as in Fan et al (2023) (11). Another explanation could be a changed energy extraction efficiency facilitated through the GM or transit time through the GI as the energy that is extracted from the food has been shown to depend on GM composition and transit time (27, 28). One could also speculate how calorie restriction is best implemented in an AN mouse model as low-calorie ad libitum food or food restriction by periodically removing food entirely from the cage mimicking uneven AN eating patterns.…”

Gut Microbiota and Microbial Metabolism in Early Risk of Cardiometabolic Disease

“…234,235 As discussed, the mechanisms are incompletely understood but may relate, in part, to the effects of microbiota on energy harvesting capacity. 79,86,87,236 Further, effects of microbiota on inflammation may, by itself, be sufficient to promote metabolic dysregulation and obesity. 146,227,237 In particular, interaction between microbes and the gut immune system during critical periods of development, including early life, may have long-lasting effects on immune programming.…”