A Prebiotic-Supplemented Formula Improves Gut Microbiota and Intestinal Inflammatory Microenvironment in Patients with Colorectal Adenoma: A Double-Blind, Placebo-Controlled Trial.

Background: Colorectal cancer is preventable, and patients with colorectal adenomas are at high risk of colorectal cancer.

Objectives: This study aimed to evaluate the effects of a complex prebiotic formulation on the gut microbiota and inflammation levels in patients with colorectal adenoma.

Methods: A randomized double-blind placebo-controlled trial assigned patients with adenomatous polyps to either the prebiotic intervention group (N = 51) or the placebo control group (N = 49). Blood and stool samples were collected at baseline and week 12; mixed-effects models were used to analyze the impact of the prebiotic on gut microbiota and inflammatory markers.

Results: Both groups showed an increase in Bacteroidetes abundance over 12 wk, but the increase was smaller in the intervention group [β = -5.507; 95% confidence interval (CI): -11.390, 0.375; P = 0.066]. Unidentified Ruminococcaceae increased in the intervention group (β = 2.072; 95% CI: -0.130, 4.274; P = 0.065), but declined in the control group. A significant increase in interleukin-10 concentrations was observed in the intervention group (β = 0.778; 95% CI: 0.132, 1.425; P = 0.019), in contrast to a downward trend in the control group. Notably, baseline tumor necrosis factor-α concentrations appeared to modify the intervention's microbial effects. Specifically, for each 1 pg/mL increase, the intervention was associated with increased Actinobacteria (β = 0.624; 95% CI: 0.100, 1.148; P-interaction ₌ 0.020), Bifidobacteriaceae (β = 0.608; 95% CI: 0.114, 1.103; P-interaction = 0.017), and Bifidobacterium (β = 0.608; 95% CI: 0.114, 1.103; P-interaction = 0.017). However, these associations did not remain statistically significant after false discovery rate adjustment.

Conclusions: The prebiotic intervention effectively increased the abundance of beneficial bacteria, while simultaneously reducing inflammatory levels in individuals with colorectal adenoma. This trial was registered at the Chinese Clinical Trial Registry as ChiCTR2100046390.