Plain language summary
A global obesity epidemic has become a growing concern today. Modifying the microbial population in our gut has been identified as a nutritional intervention strategy for managing obesity. Fermentable dietary fibres such as inulin-type fructans may alter the microbial population in the gut. In this randomised, single-blind, multicentric, placebo-controlled study, researchers examined the effect of 16g/d native inulin supplementation with inulin-rich vegetables on obesity and gut bacteria composition over three months in 106 Caucasian subjects. Furthermore, the study examined the synergistic effects of metformin and inulin on gut microbial composition. 75% of the participants lost body weight after taking inulin and making dietary changes. In addition, BMI, fat mass and other metabolic markers decreased in this group. Combined with inulin, metformin showed gut microbial modulation, although an increase in Bifidobacterium species was less noticeable. Supplementing inulin with inulin-rich vegetables caused uncomfortable side effects such as bloating and flatulence. Even though subjects showed a reduction in side effects after the first month of supplementation, it should be considered when making intervention decisions for people prone to digestive issues. Nutrition practitioners can use these results when developing obesity intervention strategies.
Abstract
BACKGROUND The gut microbiota is altered in obesity and is strongly influenced by nutrients and xenobiotics. We have tested the impact of native inulin as prebiotic present in vegetables and added as a supplement on gut microbiota-related outcomes in obese patients. Metformin treatment was analyzed as a potential modulator of the response. METHODS A randomized, single-blinded, multicentric, placebo-controlled trial was conducted in 150 obese patients who received 16 g/d native inulin versus maltodextrin, coupled to dietary advice to consume inulin-rich versus -poor vegetables for 3 months, respectively, in addition to dietary caloric restriction. Anthropometry, diagnostic imaging (abdominal CT-scan, fibroscan), food-behavior questionnaires, serum biology and fecal microbiome (primary outcome; 16S rDNA sequencing) were analyzed before and after the intervention. RESULTS Both placebo and prebiotic interventions lowered energy intake, BMI, systolic blood pressure, and serum γ-GT. The prebiotic induced greater weight loss and additionally decreased diastolic blood pressure, AST and insulinemia. Metformin treatment compromised most of the gut microbiota changes and metabolic improvements linked to prebiotic intervention. The prebiotic modulated specific bacteria, associated with the improvement of anthropometry (i.e. a decrease in Desulfovibrio and Clostridium sensu stricto). A large increase in Bifidobacterium appears as a signature of inulin intake rather than a driver of prebiotic-linked biological outcomes. CONCLUSIONS Inulin-enriched diet is able to promote weight loss in obese patients, the treatment efficiency being related to gut microbiota characteristics. This treatment is more efficacious in patients who did not receive metformin as anti-diabetic drugs prior the intervention, supporting that both drug treatment and microbiota might be taken into account in personalized nutrition interventions. Registered under ClinicalTrials.gov Identifier no NCT03852069.
Methodological quality
Jadad score
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3
Allocation concealment
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Yes
