Can Salt Weaken Your Immune System?

New research from the University of Bonn suggests that a high-salt diet can not only raise blood pressure but can also compromise the immune system. According to the researchers, an overload of salt can weaken the body's antibacterial immune defence and increase the risk of severe infection. The theory was tested on mice, with animals fed a high-salt diet suffering from more severe infections when exposed to bacteria. Human participants who increased salt consumption by six grams per day, the equivalent of consuming two fast food meals, were also diagnosed with immune deficiencies.

The findings were published in the journal Science Translational Medicine, with the team suggesting human adults should consume no more than five grams of salt a day, approximately one level teaspoon, to avoid compromising antibacterial immune defence. The guidelines are also recommended by the World Health Organisation (WHO), though figures from the Robert Koch Institute suggest that many adults exceed this limit daily.

Average adults significantly exceed salt intake recommendations

Research from the German-based government agency and research institute reveals that the average male consumers ten grams of salt per day, and the average woman consumes more than eight grams. "We have now been able to prove for the first time that excessive salt intake also significantly weakens an important arm of the immune system," says Prof. Dr. Christian Kurts, a researcher at the Institute of Experimental Immunology at the University of Bonn.

Lead author of the study Katarzyna Jobin explains that when the kidneys are forced to filter out excess salt it can cause an accumulation of glucocorticoids in the body. These hinder the function of granulocytes, a prevalent type of white blood cell that attacks bacteria and helps the immune system fight off infection. Without granulocytes, infections can quickly progress to severe.

High-salt diet increases prevalence of disease-causing pathogens

"We were able to show this in mice with a listeria infection," explains Jobin. "We had previously put some of them on a high-salt diet. In the spleen and liver of these animals we counted 100 to 1,000 times the number of disease-causing pathogens."

For Kurts, the study highlights the importance not only of limiting salt intake, but also taking research beyond the analysis of cell cultures. "Only through investigations in an entire organism were we able to uncover the complex control circuits that lead from salt intake to this immunodeficiency," says Kurts.

From investigating the immunological impact of excess salt to harnessing the therapeutic properties of cannabis, laboratory researchers play a critical role in advancing public health breakthroughs. To find out more about how scientists are extracting pharmacologically effective components such as Tetrahydrocannabinol (THC) and Cannabidiol (CBD), don't miss 'Sample Preparation of Cannabis Plants for Efficient Extraction.'