Nikhil Prasad Fact checked by:Thailand Medical News Team Oct 17, 2025 2 hours, 52 minutes ago
Medical News: Scientists Uncover the Role of Proline in Depression
A new international study has found that a common amino acid found in everyday foods could play a surprising role in causing depression. Researchers from the Girona Biomedical Research Institute (IDIBGI), Pompeu Fabra University (UPF) in Barcelona, and the Hospital del Mar Medical Research Institute (IMIM) have revealed that proline—an amino acid abundant in meat, fish, dairy, eggs, and even leafy greens—appears to influence mood through its effects on gut bacteria and brain chemistry.
Hidden Amino Acid in Everyday Foods Found to Trigger Depression
Their discovery, published in Cell Metabolism, highlights that high dietary intake and blood levels of proline are linked to more severe depression symptoms, offering a new explanation for how diet and gut health affect mental well-being. In this
Medical News report, researchers say that proline’s impact depends not just on food consumption but also on how gut microbes process and transport it to the brain.
Amino Acid that Affects Mood
Led by Dr. José Manuel Fernández-Real and Dr. Jordi Mayneris-Perxachs of IDIBGI and CIBEROBN, together with Dr. Rafael Maldonado from UPF’s Neuropharmacology Group, the team examined human volunteers, mice, and fruit flies. They measured amino acid consumption and depression levels in participants using detailed questionnaires and laboratory tests. The findings showed that higher blood concentrations of proline strongly correlated with depression indicators, even after adjusting for medications and other health factors.
Interestingly, not everyone consuming large amounts of proline-rich foods showed depressive symptoms. The difference appeared to lie in their gut bacteria composition. People with gut microbiota that efficiently metabolized and cleared proline had lower depression scores, while those with bacteria that accumulated proline in the bloodstream were more likely to experience mood disturbances.
How Gut Bacteria and the Brain Interact
The researchers found that bacterial genes responsible for breaking down and transporting proline were crucial. When these genes were active, the body maintained a healthier balance of amino acids. To confirm this, the scientists transplanted gut bacteria from depressed humans into mice. Those receiving microbiota from people with high proline levels developed depression-like behaviors and had altered brain genes controlling proline and GABA (a calming neurotransmitter) transport.
Similar results appeared in fruit fly experiments. When the flies consumed bacteria that increased proline levels, they displayed signs of behavioral despair. In contrast, flies exposed to Lactobacillus—a beneficial bacterium linked to low depression risk—showed greater resilience. Genetically modified flies lacking the ability to transport proline to the brain did not exhibit depressive behaviors at all, further strengthening the link.
Proline’s Hi
dden Role in the Gut-Brain Axis
The study highlights the microbiota-gut-brain axis as a critical factor in mental health. Proline, when excessively accumulated, disrupts neurotransmitters like glutamate and GABA, both of which regulate mood, cognition, and stress response. Disturbances in this delicate balance can alter communication between neurons, potentially triggering depressive symptoms.
These findings suggest that proline could be a missing piece in understanding depression’s biological roots and may open the door to new dietary or probiotic therapies aimed at restoring microbiome balance and amino acid metabolism.
Conclusion
According to the researchers, recognizing proline’s influence could change how depression is treated in the future. Reducing high-proline foods or modifying gut bacteria composition through targeted probiotics may help prevent or ease depressive symptoms. As depression continues to affect more than 300 million people globally, this discovery could pave the way for natural, non-drug-based interventions that harness the body’s own biological systems to promote mental health.
The study findings were published in the peer reviewed journal: Cell Metabolism.
https://www.cell.com/cell-metabolism/fulltext/S1550-4131(22)00128-0
For the latest on Depression and other menta health issues, keep on logging to Thailand
Medical News.
Read Also:
https://www.thailandmedical.news/articles/mental-health
https://www.thailandmedical.news/articles/diets-and-nutrition
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