Henan Provincial People’s Hospital Trial Compares High-Fiber Diet and Metformin

An 84-day trial conducted at Henan Provincial People’s Hospital in China compared a high-fiber dietary intervention directly against standard metformin monotherapy for adults diagnosed with diabesity. The dietary intervention produced greater improvements in both glycated hemoglobin and body mass index than the standard pharmaceutical treatment.

Key Clinical Takeaways:
• Adults following the high-fiber diet achieved a mean HbA1c of 6.3% by Day 84, compared to 6.7% in the metformin group.
• Participants in the dietary intervention recorded a mean BMI of 28.4 kg/m², while the metformin cohort averaged 30.2 kg/m².
• Shotgun metagenomic analysis revealed that fiber enriched bacteria including Bifidobacterium and Lactobacillus within 28 days while depleting Bilophila wadsworthia.

Trial Design and Participant Demographics at Henan Provincial People’s Hospital

The open-label, head-to-head trial evaluated 48 adults aged 18 to 70 years with newly diagnosed type 2 diabetes mellitus and concurrent obesity. Eligible participants exhibited a baseline HbA1c between 6.5% and less than 9.0% alongside a body mass index of at least 24 kg/m². Following a two-week run-in period, investigators randomized participants to either a high-fiber diet without medication or metformin monotherapy. Thirty-four participants completed the high-fiber intervention, while 12 completed the metformin regimen. The high-fiber diet utilized specific formulas providing soluble and insoluble fibers, including inulin and resistant dextrin.

Glycemic Control and Weight Outcomes at Day 84

Primary outcomes measured at Day 84 showed distinct metabolic differences between the two cohorts after adjusting for baseline values. Participants assigned to the high-fiber diet demonstrated lower baseline-adjusted HbA1c levels and reduced mean BMI figures compared to those taking metformin. Continuous glucose monitoring data indicated diminished glycemic variability alongside lower whole-body fat mass and triglyceride concentrations in the dietary group. Researchers noted that participants in the high-fiber arm consumed lower amounts of energy and several macronutrients during the study period, which may have influenced weight-related outcomes.

High-Fiber Intervention Alters Gut Microbial Community Structures

Metagenomic sequencing of 184 serial fecal samples tracked structural and functional changes in the gut microbiome over the 84-day timeframe. The high-fiber intervention altered microbial community structures within 28 days by enriching bacteria and decreasing populations of Bilophila wadsworthia, a bacterium associated with chronic inflammation. Conversely, the metformin group displayed no significant alterations in overall microbial community structure during the trial. Functional profiling identified an increased abundance of the acetate-production gene formate-tetrahydrofolate ligase at Days 28 and 56 in the fiber group, alongside reduced levels of hydrogen sulfide-production genes by Day 84.

Investigators acknowledged several constraints that limit the broader clinical applicability of the findings. The single-center trial relied on a small total completion cohort of 46 participants, with an unequal distribution leaving only 12 individuals in the metformin arm. The short duration of the study and the lack of direct GLP-1 level measurements mean that the precise physiological mechanisms linking short-chain fatty acids to metabolic improvements remain unconfirmed. Larger independent clinical trials are required to determine whether baseline microbial profiles can reliably predict which patients will respond best to targeted dietary interventions.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider regarding any medical condition, diagnosis, or treatment plan.