Eating too much salt might rev up the immune system in the guts and blood vessels of mice, leading to more inflammation and signs of immune cell activity.

What we've found so far is that the evidence we've reviewed leans toward a high salt diet being linked to increased immune activity and inflammation in the gut and blood vessels of mice. Our analysis of the available research shows this is based on findings from 20.0 studies that support this link, with no studies refuting it [1]. We looked at what happens in mice when they eat a lot of salt. The evidence suggests their immune systems may become more active, especially in the gut and blood vessels. This comes with signs of inflammation and increased activity of immune cells. These are markers that the body is mounting an immune response, though we don’t know from this evidence alone whether that response is harmful or protective in the long term [1]. It’s important to note that all the data we’ve reviewed so far comes from mouse studies. We can’t say whether the same effects happen in humans. Also, while the evidence consistently supports this link in mice, we don’t yet know how much salt is needed to trigger these changes, or how long those effects last. Our current analysis shows a clear pattern in mice: higher salt intake is associated with immune activation and inflammation in the gut. But since we’re only reviewing what’s been studied so far, our understanding could change as more evidence comes in. Practical takeaway: In mice, eating a lot of salt seems to turn up immune activity in the gut. We don’t know if that happens in people, but it’s another reason to think twice about very high salt diets.