Resistant Starch Intake Facilitates Weight Loss in Humans by Reshaping the Gut Microbiota
A 20-week randomized, placebo-controlled crossover study investigated the effects of resistant starch (RS) supplementation on weight loss and metabolic health in 37 adults with overweight or obesity. Participants alternated between an 8-week RS intervention (40 g/day) and a control starch (CS) intervention, separated by a 4-week washout period. Researchers measured body weight, fat distribution, glucose metabolism, gut microbiota composition, and bile acid profiles using anthropometric assessments, MRI, meal tolerance tests, and multi-omics analyses.
The results revealed that the 8‑week RS intervention produced a significant reduction in body weight (mean net change of −2.81 kg; 95% CI, −3.55 to −2.07 kg), along with a decrease in fat mass, waist circumference, and both visceral and subcutaneous fat areas measured by MRI. Improvements in glucose tolerance and insulin sensitivity were also demonstrated and reduced insulin concentrations following a meal tolerance test. Additionally, RS supplementation was associated with lower levels of pro-inflammatory cytokines (TNFα and IL‑1β), increased serum adiponectin, and higher fecal lipid excretion, indicating lower dietary lipid absorption. Metagenomic analyses showed that RS reshaped the gut microbiota, notably increasing the abundance of species such as Bifidobacterium adolescentis and Ruminococcus bromii; subsequent FMT experiments in mice provided causative evidence that these microbiota alterations help mitigate diet-induced obesity.
These findings support the conclusion that RS promotes weight loss and metabolic improvements through gut microbiota-mediated mechanisms. However, the study highlights limitations such as its small sample size and short intervention duration. Future research should explore long-term effects of RS supplementation and its potential for broader clinical applications. Overall, this study reinforces the role of dietary fiber interventions in combating obesity and metabolic disorders through gut microbiota modulation.
