How Protein Deficiency Affects the Gut
New research reveals that the gut responds to a lack of protein through two coordinated pathways involving the hormone CNMa, which selectively reshapes dietary choices. Published in the journal Science on May 28 at 6:30 PM, the study used fruit flies and mice to explore the underlying mechanisms. The hormone is released by specialized gut cells when protein levels drop.
One pathway works by activating enteric neurons, which send signals to the brain via nerve channels, informing the body about the protein shortage and prompting behavioral adjustments. The second pathway involves CNMa traveling through the bloodstream, which intensifies long-term foraging for protein-rich foods. Together, these routes ensure a targeted response to nutritional deficits.
Importantly, CNMa signals also suppress the activity of DH44 neurons, which are responsible for sensing sugar. This mechanism helps the body prioritize protein seeking over sugar consumption when protein is scarce. Gut bacteria play a key role in regulating this process, potentially influencing overall eating behavior. The study notes that mammals may have additional, yet-to-be-identified nutrient-sensing systems.
Study authors emphasized that 'the gut is not just a digestive organ, but an active sensory system.'
These findings open new avenues for understanding how the body adapts to dietary changes and the mechanisms driving such responses. The publication DOI is 10.1126/science.adv3355.
Scientific Implications of the Study
Conducted on fruit flies and mice, this research underscores the gut's role not only in digestion but also as an active component of the nervous system that reacts to nutritional shifts. The identified mechanisms could inform new treatments for eating disorders and clarify how microbiota influence behavior during nutrient deficiencies. The study also encourages further investigation into how these processes may differ across species, including humans.