A recent study has found that a high-sodium diet (HSD) can lead to depressive symptoms in rats, by stimulating the production of a protein called 'IL-17A'. This protein has previously been linked to depression in human clinical studies. Published in the journal 'Immunity', the research discovered that immune cells known as 'gamma-delta T-cells' are a major source of 'IL-17A' production in rats on an HSD, accounting for about 40% of the cells producing this protein. When these cells were removed, the depressive symptoms caused by the high-sodium diet were alleviated. The study highlights the health risks associated with excessive sodium consumption, which is linked to a number of chronic diseases such as cardiovascular diseases, neuroimmune disorders, and depression. Dr. Xiaojun Chen from Nanjing Medical University, who led the study, said: 'These findings support dietary interventions like reducing salt intake as a preventive measure against mental illnesses and open new avenues for therapeutic strategies targeting IL-17A for depression treatment.' He added: 'We hope these results will encourage broader discussions on salt consumption guidelines.' In the experiment, rats were fed either a normal diet or a high-sodium diet for five weeks, a timeframe used to study the effects of excess salt. Rats on the high-sodium diet showed decreased activity and increased lethargy, reflecting depressive symptoms. When the production of IL-17A was blocked in the rats, depressive symptoms did not appear, proving the crucial role of this protein in triggering depression. The study emphasizes the need for more research to understand the immune mechanisms involved in depression, and the scientists hope these findings will contribute to the development of new drugs targeting IL-17A or 'gamma-delta T-cells' to mitigate the effects of diet-induced depression.
