More and more studies are showing a strong connection between obesity and the gut microbiome. One team recently found that severe obesity is associated with a distressed gut microbiome, shown by low levels of microbial diversity and abnormal levels of microbiome-associated metabolites in circulation (1). In fact, in this study, around 75% of severely obese participants had low microbial gene richness, compared to 20-40% of moderately obese individuals. 

Weight loss surgery is one method commonly used to achieve weight loss and decrease risk of chronic diseases. While such an intervention often has positive results, post-surgical weight loss is not accompanied by a full recovery of the gut microbiome. Bariatric surgery was found to increase microbial diversity by 25-40%, but even with this increase these individuals maintain a microbiome that is much less diverse than the average healthy weight individual. These differences were still found even one year after surgery, when optimal weight loss was achieved. Strikingly, some individuals had lower microbial diversity still 5 years post-surgery. When further analysed, the authors found nine metabolites that were affected by changes in the microbiome after weight loss surgery.  

The slight improvements in microbial diversity after bariatric surgery are encouraging. Given that severely obese individuals continue to have lower levels of diversity even after surgical intervention, and given the identified metabolites correlated with changes in the microbiome after surgery, there may be strategies that can further improve the microbiome in those with severe obesity along with surgery to further improve metabolic function. Integrative Phenomics continually seeks advancement in research to support the microbiome during the weight loss process, and to identify personalized nutrition approaches to optimize weight loss and health. 

1. Aron-Wisnewsky J, Prifti E, Belda E, et al. Major microbiota dysbiosis in severe obesity: fate after bariatric surgery. Gut.2019;68:70-82.