A growing body of literature ties the gut microbiome to symptoms of depression in a seemingly circular relationship where each affects the other. However, many of the studies on this relationship merely link certain bacterial populations or diets to major depressive disorder—leaving open critical questions about the underlying mechanisms of how the gut microbes might influence depression.
Research published in Cell Metabolism takes an important step toward filling such gaps, demonstrating in multiple animal species that there is likely a causative relationship between depression severity and serum levels of the nonessential amino acid proline, which the study finds depend on both diet and the activity of proline-metabolizing bacteria in the gut.
“To the best of my knowledge, this is the first time that a team actually demonstrates a causal relationship between proline intake and depressive behavior,” University of Reading metabolism researcher Sandrine Claus, who didn’t work on the study and ...
