Reaching for the salt shaker often isn’t just bad for your blood pressure and heart, but also hurts your immune system, according to a recent study conducted at the University of Bonn and published in the journal – Science Translational Medicine.
- WHO recommends that adults should consume a maximum of one level teaspoon or 5 grams of salt in a day.
- In reality, however, we exceed this limit considerably, with men on average consuming 10 grams and women taking more than 8 grams of salt a day.
This excessive salt intake doesn’t just increase the risk of heart attack and stroke, but according to this study, it also weakens the immune system.
This comes in contrast to a few previous studies that suggested that salt has an immune-enhancing effect in infections involving skin parasites. Katarzyna Jobin, lead author of the study explains that the body uses skin like a salt reservoir while keeping the concentration of salt in the blood and the organs largely constant. This explains why additional salt intake helps in the case of some skin diseases.
Any additional salt that we consume with food, is filtered out by the kidneys and excreted as urine. This is when salt begins harming the immune system.
Our kidneys have a sensor that activates the salt excretion. Other than helping the kidneys excrete excess salt, this sensor also causes accumulation of glucocorticoids in the body. The accumulated glucocorticoids, in turn, inhibit the function of granulocytes – immune cells in the blood that help fight bacteria – leaving us exposed to severe bacterial infections.
Volunteers in this study consumed 6 grams of salt, in addition to their daily intake, which is roughly the salt in 2 burgers and 2 portions of French fries.
A week later, when their blood was examined for immune cells, the researchers found that they showed an increase in glucocorticoid levels and their immune cells coped much worse with bacteria that they did before the salt consumption.
The key take-away from this amid the current climate? Put that salt shaker away during meals, avoid processed foods and foods with a high salt content, and help your immune system do its job.
Katarzyna Jobin, Natascha E. Stumpf, Sebastian Schwab, Melanie Eichler, Patrick Neubert, Manfred Rauh, Marek Adamowski, Olena Babyak, Daniel Hinze, Sugirthan Sivalingam, Christina K. Weisheit, Katharina Hochheiser, Susanne Schmidt, Mirjam Meissner, Natalio Garbi, Zeinab Abdullah, Ulrich Wenzel, Michael Hölzel, Jonathan Jantsch and Christian Kurts, A high-salt diet compromises antibacterial neutrophil responses through hormonal perturbation, Science Translational Medicine, DOI: 10.1126/scitranslmed.aay3850