Bariatric surgery as a long-term modulator of gut microbiota


Obesity represents one of the most important problems worldwide and is linked to morbidity and mortality. Clinical management of this pathology is based mainly on lifestyle interventions. When the nonsurgical alternatives fails, bariatric surgery is considered the gold standard treatment for patients. Benefits of this treatment include weight loss and modifications in metabolites, and most recently, several studies have demonstrated that this surgical approach could reshape the gut microbiota, for example enriching bacterial diversity and increasing the capacity for energy harvest. As this technique could drive a shift of the metabolic capacity of the gut microbiota, both from a composition and from a functional point of view, this study wanted to use a multiomics approach to characterize the impact of bariatric surgery of patients with severe obesity on gut microbiota.

Results showed that bariatric technique enhanced biochemical and anthropometric parameters compared with measurements taken before surgery, including body weight and body mass index (BMI), body fat percentage, glucose, insulin, uric acid and several protein concentration.The multiomics approach showed differences in faecal microbiota composition associated to bariatric surgery compared to samples collected before the intervention; moreover, surgery significantly modified the faecal metabolome of patients. In particular, the abundance of methyl acetoacetate,carbamoyl aspartate and serine phosphate were significantly reduced, whereas other metabolites such as taurine and tropic acid were increased. Among the short-chain fatty acids (SCFAs), the concentrations of acetate, butyrate and proprionate were reduced, and this decrease is involved in the improvement of obesity.

Taken together, these data demonstrated that bariatric surgery could have effects on the form and the function of gut microbiota, improving the health status of patients. Further studies with larger cohorts and collection of additional informations on the lifestyle of patients are needed to obtain more statistical power and to guarantee that these changes are due only to the surgery, but the homogeneity of these results showed that there is a common cause of the modifications that should be attributed to bariatric surgery, as a long-term modulator of gut microbiota.

Comment by Stefania Blasa

Related Journal Article: “Long-term effects of bariatric surgery on gut microbiota composition and faecal metabolome related to obesity remission” published on Nutrients 2021 July 23, 13 (8), 2519, doi:; PMID: 34444679

<a href="" target="_self">Stefania Blasa</a>

Stefania Blasa

Stefania Blasa is a Postdoc in “Converging Technologies for Biomolecular Systems” at University of Milan-Bicocca; she is interested in neurophysiology and works on in-vitro neuronal differentiation induced by innovative technologies. During her master thesis, she worked on the simultaneous detection of mutations responsible of peripheral nerve system genetic diseases.