Weight‐loss interventions and gut microbiota changes in overweight and obese patients: a systematic review

Abstract

Imbalances in the gut microbiota, the bacteria that inhabit the intestines, are central to the pathogenesis of obesity. This systematic review assesses the association between the gut microbiota and weight loss in overweight/obese adults and its potential manipulation as a target for treating obesity. This review identified 43 studies using the keywords 'overweight' or 'obesity' and 'microbiota' and related terms; among these studies, 17 used dietary interventions, 11 used bariatric surgery and 15 used microbiota manipulation. The studies differed in their methodologies as well as their intervention lengths. Restrictive diets decreased the microbiota abundance, correlated with nutrient deficiency rather than weight loss and generally reduced the butyrate producers Firmicutes, Lactobacillus sp. and Bifidobacterium sp. The impact of surgical intervention depended on the given technique and showed a similar effect on butyrate producers, in addition to increasing the presence of the Proteobacteria phylum, which is related to changes in the intestinal absorptive surface, pH and digestion time. Probiotics differed in strain and duration with diverse effects on the microbiota, and they tended to reduce body fat. Prebiotics had a bifidogenic effect and increased butyrate producers, likely due to cross-feeding interactions, contributing to the gut barrier and improving metabolic outcomes. All of the interventions under consideration had impacts on the gut microbiota, although they did not always correlate with weight loss. These results show that restrictive diets and bariatric surgery reduce microbial abundance and promote changes in microbial composition that could have long-term detrimental effects on the colon. In contrast, prebiotics might restore a healthy microbiome and reduce body fat.

Microbiome, bile acids, and obesity: How microbially modified metabolites shape anti‐tumor immunity

“…From a recent meta-analysis, bariatric surgery-and associated physiologic and metabolic changes-significantly reduced all-cause mortality from cancer (~33%-60%). [117][118][119][120][121][122][123][124][125][126][127][128][129][130][131] Retrospective studies found bariatric surgery significantly reduced risk for preand postmenopausal BC as well as skin cancer (including melanoma). 123,132 Of note for subtype-specific BC, bariatric surgery led to a 64% reduced risk in premenopausal ER tumors like TNBC.…”

Chronic water insufficiency induced kidney damage and energy dysregulation despite reduced food intake, which improved gut microbiota in female rats

“…Calorie restriction increases the microbiota richness and diversity that is correlated with nutrient deficiency rather than weight loss [10]. Calorie restrictive diets generally reduce the butyrate-producing bacteria such as Firmicutes, Lactobacillus, and Bifidobacterium species [39]. The changes in gut microbiota resulting from calorie restriction are similar to those induced by bariatric surgery in experimental animals and humans [39,40].…”

“…Calorie restrictive diets generally reduce the butyrate-producing bacteria such as Firmicutes, Lactobacillus, and Bifidobacterium species [39]. The changes in gut microbiota resulting from calorie restriction are similar to those induced by bariatric surgery in experimental animals and humans [39,40]. Calorie restriction and bariatric surgery modulate bile acid metabolism to increase circulating bile acid concentrations and reduced the secondary bile acid production.…”

Good or bad: gut bacteria in human health and diseases

“…Increasing evidence suggests that gut microbiota dysbiosis would lead to a number of diseases, including gastrointestinal disorders [2,[33][34][35], obesity [36][37][38], cardiovascular diseases [39][40][41], allergy [42][43][44] and CNS-related diseases [30,45], which affect a large population in the world. Besides, mood and behaviour are also susceptible to alterations in the gut microbiota [3].…”