High-salt intake bad for the immune system

A high-salt diet is bad for the immune system, as well as blood pressure, a study in Germany found.

Mice fed a high-salt diet by researchers from the University Hospital Bonn were found to suffer from much moresevere bacterial infections. Human volunteers who consumed an additional six grams of salt per day (one gramabove the World Health Organization recommendations) also showed pronounced immune deficiencies. Thisamount corresponds to the salt content of two fast food meals, according to the study published in thejournal Science Translational Medicine.

Sodium chloride raises blood pressure and thereby increases the risk of heart attack or stroke. But not only that:"We have now been able to prove for the first time that excessive salt intake also significantly weakens an important armof the immune system," said Prof. Dr. Christian Kurts from the Institute of Experimental Immunology at theUniversity of Bonn.

He added the finding was unexpected, as some studies have observed that sodium chloride has a generallyimmune-enhancing effect. For example, infections with certain skin parasites in laboratory animals heal significantly faster if these consume a high-salt diet: the macrophages, which are immune cells that attack, eat anddigest parasites, are particularly active in the presence of salt.

Kurts told FoodNavigator that it was too early to say if the study's findings would be significant amid the COVID-19crisis as consumers seek ways to boost their immune systems, and that no studies on salt and COVID-19 had beendone. He was also pessimistic that the results would alter salt intake in Europe. Figures from the Robert KochInstitute suggest that on average in Germany men consume ten, and women more than eight grams a day.

“I can't imagine the industry will take notice," we were told. "We did not study virus responses, although there is a chancea high salt diet also affects antiviral responses, because the mechanism we identified has been shown by others to impairthe defence against influenza pneumonia."