High-Salt Diet Linked to Depression, Study Unveils - Video

A new study published in The Journal of Immunology found that a high-salt diet (HSD) induces depression-like symptoms in mice by driving the production of a protein called IL-17A. This protein has previously been identified as a contributor to depression in human clinical studies.

The researchers also identified a type of immune cell called gamma-delta T cells as an important source of IL-17A in HSD-fed mice, accounting for ~40% of IL-17A-producing cells.

High-salt intake is ubiquitous in the Western diet, with fast foods often containing 100 times more salt than a home-cooked meal. HSD is already an important public health concern as it is linked to cardiovascular, autoimmune, and neurodivergent diseases. Furthermore, major depression disorder is also a significant public health concern with a lifetime prevalence of 15-18%.

In this study, mice were fed a normal diet or HSD for 5 weeks, a common timeframe used to study excessive dietary salt intake. After five weeks, the mice fed the HSD showed less interest in exploring and more inactivity in various scenarios compared to mice fed a normal diet, suggesting depression-like symptoms in mice

Given the already established role of IL-17A in the development of depression, the research team also investigated whether HSD induced IL-17A production in mice. HSD increased IL-17A levels in the spleen, blood, and brain, correlating with anxiety- and depression-like behaviors. However, when mice that could not produce IL-17A were fed an HSD, depression-like symptoms were not observed, confirming the role of IL-17A in developing depression-like symptoms.

These findings corroborate epidemiological evidence that HSD correlates strongly with more severe depression and studies in people demonstrating that low sodium intake is closely associated with good mood.