Overlooked plant proteins may boost gut health - Medical Xpress

What the report says

Medical Xpress reported July 28 that two studies led by Jenna AbuSalim and Joshua Rabinowitz of Ludwig Princeton point to a larger role for plant proteins in shaping gut chemistry than has been widely recognized. The work, published in Proceedings of the National Academy of Sciences and Nature Metabolism, examines how diet and host biology influence phenol and indole metabolites, compounds linked in prior research to gut, metabolic, immune and disease-related processes.

In the PNAS study, the researchers found that both plant fiber and digestion-resistant plant proteins shifted gut microbial metabolism toward phenylalanine-derived metabolites such as phenylpropionate and hippuric acid, which the article describes as associated with gut health and healthy body weight. At the same time, they reduced production of tyrosine-derived compounds such as p-cresol sulfate and phenol sulfate, which have been associated with worse outcomes in some cancer patients and toxicity in kidney disease. The team calls these resistant proteins “proteins imitating fiber,” or Prif, and suggests they may work alongside fiber by giving microbes more dietary protein to process while fiber limits bacterial breakdown of the gut mucus lining.

The Nature Metabolism study complicates a common assumption about metabolites often credited mainly to the microbiome. Using isotope-tracing work in mice, rats and human cells, the researchers reported that mammalian metabolism can also generate many indole and phenol metabolites, while some compounds remained clearly microbe-dependent.

The findings matter because scientists and clinicians are increasingly interested in diet, probiotics or metabolite-based therapies to influence the microbiome. The article frames the research as a step toward more precise nutrition guidance, while the evidence so far is mechanistic and should not be read as a clinical recommendation on its own.