Eating Oranges May Lower Depression Risk: New Study Reveals Gut Connection

The researchers note that while the gut microbiome plays a crucial role in mediating the effects of diet on overall health, the specific interactions between certain foods, microbial features, and depression risk remain unclear. To explore this connection, Raaj S. Mehta, Clinical and Translational Epidemiology Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA, and colleagues analyzed decades of dietary and depression data from a long-term cohort of 32,427 women. Additionally, they examined fecal metagenomics and plasma metabolomics in a subset of 207 participants, further validating their findings in an independent cohort of 307 men.

The study led to the following findings:

• Higher citrus intake and its components were linked to a reduced risk of depression.
• Citrus consumption influenced the abundance of 15 gut microbial species, including an increase in Faecalibacterium prausnitzii.
• Participants with depression had lower levels of F. prausnitzii and reduced activity in its metabolic pathway, the S-adenosyl-L-methionine (SAM) cycle I.
• Further analysis suggested that decreased SAM production by F. prausnitzii may lower intestinal monoamine oxidase A gene expression, which plays a role in serotonin and dopamine synthesis.

The researchers highlighted the significant role of diet in depression prevention, emphasizing how the gut microbiome mediates the impact of citrus on mental health. Their findings suggest that citrus consumption may protect against depression, potentially through the modulation of Faecalibacterium prausnitzii and its metabolic activity.

"Given the limitations of current pharmacological treatments, our study supports the potential of the gut microbiome in developing novel biomarkers and dietary interventions to reduce depression risk," the researchers concluded.

Reference:

Samuthpongtorn, C., Chan, A.A., Ma, W. et al. F. prausnitzii potentially modulates the association between citrus intake and depression. Microbiome 12, 237 (2024). https://doi.org/10.1186/s40168-024-01961-3