Researchers discover gut-brain circuit that drives protein cravings

The Story

Scientists at the Institute for Basic Science (IBS), working with researchers from Seoul National University and Ewha Womans University, identified a previously unknown gut-brain signaling network that reshapes cravings when the body needs protein. The discovery, published in the journal Science on May 21, was made using fruit flies and mice and may affect understanding of appetite, nutrition, and obesity.

Key Facts

• The team, led by Director SUH Seong-Bae of the IBS Center for Microbiome-Body-Brain Physiology, included scientists from Seoul National University and Ewha Womans University.
• The findings were published in the journal Science on May 21.
• In fruit flies, protein deficiency caused specialized intestinal cells to release a peptide hormone called CNMa.
• CNMa activated enteric neurons that transmitted signals to the brain via a direct gut-brain neural pathway, and also traveled through the bloodstream as a hormone.
• The system increased attraction to protein-related nutrients and reduced interest in sugar by suppressing activity in sugar-sensitive DH44 neurons.
• Fruit flies lacking normal gut microbes showed stronger activation of amino acid-seeking brain neurons.
• Experiments in mice showed that protein-deprived mice developed a strong preference for essential amino acids.
• Even mice lacking FGF21, a hormone previously thought central to protein appetite, still showed amino acid-seeking behavior.
• The researchers suggest that additional nutrient-sensing systems exist that have not yet been identified.
• The study may help improve understanding of obesity, metabolic disease, and eating disorders.

Conflicting Reports

No conflicting reports identified in the source article.

Still Unclear

• The specific additional nutrient-sensing systems that scientists have not yet identified.
• How these findings might translate to human applications or therapies.

Misconceptions

No widespread misconceptions addressed in the source article.

Key Figures

• Director SUH Seong-Bae – Director of the Center for Microbiome-Body-Brain Physiology at the Institute for Basic Science (IBS)
• Boram Kim – listed as first author in the journal reference

Sources

• https://www.sciencedaily.com/releases/2026/05/260527023202.htm — Primary Source