Emory Study Finds High-Fat Diets Can Send Gut Bacteria to the Brain

Research suggests gut microbiome changes from Western diets may initiate neurological conditions

Mar. 13, 2026 at 5:40am

Got story updates? Submit your updates here. ›

A new study from Emory University explains the gut-brain connection, indicating that live bacteria from an imbalanced gut microbiome can directly enter the brain via the vagus nerve, with potential implications for neurological health. The study found that mice fed a high-fat, Western-style diet experienced increased intestinal permeability, allowing bacteria to travel from the gut to the brain without detection in the blood or other organs.

Why it matters

This research highlights the significant influence that dietary shifts can have on human behavior and neurological health, potentially shifting the focus of new interventions for brain conditions to target the gut microbiome rather than the brain itself.

The details

During the study, germ-free mice consumed a high-fat, Western-style diet for nine days, leading to gut microbiome changes associated with increased intestinal barrier permeability. This enabled live bacteria to travel directly from the intestine to the brain via the vagus nerve, without appearing in the blood or other organs. Administering antibiotics to kill gut microbes, then feeding the mice an engineered bacterium, confirmed this pathway. The researchers also found low levels of bacteria in the brains of mouse models of neurological diseases like Parkinson's and Alzheimer's.

  • The study was published in PLOS Biology in March 2026.
  • The mice consumed the high-fat diet for nine days.

The players

David Weiss

Co-principal investigator of the study, microbiologist and professor at Emory University's School of Medicine.

Arash Grakoui

Co-principal investigator of the study, professor of medicine, microbiology and immunology at Emory University.

Emory University

The university where the study was conducted.

Got photos? Submit your photos here. ›

What they’re saying

“One of the biggest translational aspects of this study is that it suggests that the development of neurological conditions may be initiated in the gut.”

— David Weiss, Co-principal investigator (Mirage News)

“This may shift the focus of new interventions for brain conditions, with the gut as the new target of the therapy. That potential anatomical shift of the target could have an unbelievable impact on how people with neurological conditions benefit from therapies.”

— David Weiss, Co-principal investigator (Mirage News)

“This research highlights the need for further study into how dietary shifts have a huge influence on human behavior and neurological health.”

— Arash Grakoui, Co-principal investigator (Mirage News)

What’s next

Researchers noted that returning the mice to a normal diet restricted bacterial load in the brain by decreasing gut permeability, indicating the impact of a high-fat diet on bacteria reaching the brain can be reversible. Further studies are needed to explore the implications for human neurological health.

The takeaway

This groundbreaking research suggests that the development of neurological conditions may originate in the gut, rather than the brain itself, opening up new avenues for potential interventions and treatments targeting the gut microbiome.