NANJING — A new study suggests that eating too much salt may do more than raise blood pressure—it could also affect mental health by triggering changes in the immune system that lead to depression-like symptoms.
Researchers at Nanjing Medical University fed mice a high-salt diet for five weeks and found that they became less active and showed signs of depression. In contrast, mice on a normal diet did not.
The team focused on a protein called IL-17A, which is part of the immune system. Mice on the high-salt diet had much higher levels of this protein in their blood, spleen, and brain. Those that lacked IL-17A did not show depression-like behavior, even with high salt intake.
“We believe salt reduction could help prevent mental illness,” said lead researcher Dr. Xiaojun Chen. “Targeting IL-17A may also lead to new treatments for depression.”
The study also found that a type of immune cell—gamma-delta T cells—produced nearly 40% of the IL-17A in high-salt mice. When these cells were removed, the mice’s depression-like behavior disappeared.
With processed and fast foods often loaded with salt, the researchers warn that excessive salt may harm not only the heart but also the brain. Prior human studies have shown people with lower sodium intake tend to report better moods.
Next, the researchers aim to test their findings in people and explore how salt activates these immune cells. They also hope to investigate whether existing IL-17A-blocking drugs could help treat depression.
Until then, their advice is simple: eat less salt—not just for your heart, but for your mind.
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