High-Salt Diet May Increase Risk of Depression, Study Finds

A groundbreaking study from Nanjing University in China, published on March 22, 2025, in The Journal of Immunology, suggests a potential link between high salt intake and the development of depression-like symptoms.

The Study at a Glance

Researchers divided lab rats into two groups:

• One group received a standard diet

• The other group consumed a high-salt diet for five weeks

Afterward, the rats underwent behavioral tests to assess mood and activity levels. The results were striking: rats fed the high-salt diet showed less interest in exploring their environment and were less active overall, behaviors commonly associated with depressive states.

What’s the Biological Link?

The researchers focused on a protein called IL-17A, a cytokine involved in immune responses and inflammation, which has been previously linked to depression in humans.

They discovered that rats on the high-salt diet had elevated IL-17A levels in the spleen, blood, and brain — particularly in the hippocampus and prefrontal cortex, both key regions involved in mood regulation.

To test whether IL-17A was actually causing the mood-related symptoms, the researchers studied genetically modified rats lacking IL-17A. Interestingly, even when these rats consumed a high-salt diet, they did not exhibit the depression-like behavior seen in the regular rats. This finding strongly suggests that IL-17A plays a central role in the connection between diet and mood.

Additionally, the study found that removing specific immune cells using antibodies helped reduce depressive behaviors, pointing to a possible new therapeutic target.

Expert Insight

Dr. Xiaojun Chen, the lead researcher, noted: “Our work supports the use of dietary interventions, such as reducing salt intake, as a preventive strategy for mental health disorders. It also opens the door to new treatments targeting IL-17A for depression.”

The Bigger Picture: Diet and Mental Health

These findings highlight the growing understanding that what we eat affects not only our physical health but also our mental well-being. A simple reduction in salt intake may be an effective and accessible way to lower the risk of developing depressive symptoms.