Study Links Depression with High Levels of an Amino Acid

Experiments in animals and observations in humans suggest that the amount of proline circulating in one’s plasma has a strong association with depression severity.

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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 last month (May 3) 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,” King’s College London metabolism researcher Sandrine Claus, who didn’t work ...

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    Dan Robitzski

    Dan is a News Editor at The Scientist. He writes and edits for the news desk and oversees the “The Literature” and “Modus Operandi” sections of the monthly TS Digest and quarterly print magazine. He has a background in neuroscience and earned his master's in science journalism at New York University.
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