Resistant starch decreases intrahepatic triglycerides in patients with NAFLD via gut microbiome alterationsOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This randomized placebo-controlled trial tested whether resistant starch (RS), a microbiota-directed dietary supplement, can treat non-alcoholic fatty liver disease (NAFLD). NAFLD lacks effective interventions. The 4-month trial paired the clinical work with metagenomics and metabolomics to link gut bacteria, blood metabolites and liver fat. Researchers also used fecal microbiota transplantation and monocolonization in mice to test whether the microbiota changes could cause the effect on liver fat.
Who was studied?
The trial enrolled people with NAFLD and compared a resistant starch group (n = 99) with a control group (n = 97). This was a human dietary intervention over four months. Participants were part of a registered clinical trial, with both arms following the same background conditions apart from the starch supplement. Supporting causal experiments were then run in mice using fecal microbiota transplantation and monocolonization to probe the mechanism behind the human results.
What were the most important findings?
Resistant starch reduced liver fat substantially. Intrahepatic triglyceride content dropped by 9.08% relative to control, and by 5.89% after adjusting for weight loss. Serum branched-chain amino acids and specific gut species, notably Bacteroides stercoris, correlated with liver fat and liver enzymes and were reduced by the supplement. Multi-omics analysis tied together the microbiota shift, lower branched-chain amino acid availability and reduced hepatic steatosis, with mouse transplantation and monocolonization supporting a causal chain.
What are the greatest implications of this study?
The findings suggest resistant starch could be a practical dietary strategy for NAFLD by reshaping gut microbiota composition and function, especially by lowering Bacteroides stercoris. Because part of the liver-fat reduction persisted after adjusting for weight loss, the benefit seems only partly explained by weight change. The mouse experiments strengthen but do not fully prove causation in humans. Longer and larger trials are needed to confirm durability and clinical relevance.