Researchers discover nutrient linked to depression

Proline identified as key compound

The amino acid proline, commonly present in foods such as gelatin, beef, and fish, has been linked to a higher likelihood of developing depressive symptoms, according to a study published in Cell Metabolism.

The research team — led by Dr José Manuel Fernández-Real and Dr. Jordi Mayneris-Perxachs from IDIBGI and CIBEROBN, along with Dr. Rafael Maldonado from UPF — analyzed participants’ amino acid intake and mood assessments to explore dietary effects on mental health.

Strong correlation between proline and mood

Dr Fernández-Real, who also chairs the Department of Medical Sciences at the University of Girona, said the team was surprised to find that proline consumption showed the strongest correlation with depressive symptoms.

Blood tests revealed that elevated plasma proline levels were one of the main metabolic indicators associated with depression.

Gut Microbiota’s role in mental health

Further analysis highlighted the influence of gut microbiota, showing that bacterial composition affects how proline is processed in the body. Interestingly, participants with specific gut bacteria exhibited fewer depressive symptoms even with high proline intake.

Animal studies support findings

Experiments on mice and fruit flies confirmed the link: animals with altered proline metabolism displayed depression-like behavior.

The findings suggest that proline may play a direct role in mood regulation, paving the way for diet-based strategies to improve mental health.