Can salt fight tumours?
doi:10.1038/nindia.2021.120 Published online 15 September 2021
Although salt has often been linked to various health challenges – such as increased heart attack risk and elevated blood pressure – researchers at India’s Translational Health Science and Technology Institute (THSTI) in Faridabad have shown that a diet high in salt is able to suppress tumour progression in mice1.
Many of the health disorders above are associated with the strong inflammatory response elicited by salt. At THSTI, the researchers have harnessed this very property of salt to fight against tumours.
“Since high salt had recently been shown to activate the immune response, we reasoned that a high-salt diet (HSD) when given to tumour-bearing mice may be helpful in promoting tumour immunity,” Amit Awasthi, an associate professor at THSTI and the group leader of this study told Nature India. “Our study shows that HSD was able to suppress the tumour progression through activation of immune cells called natural killer (NK) cells.”
One of the striking findings of the study was that HSD made the gut barrier leaky, resulting in translocation of Bifidobacteria (one of the major genera of bacteria that make up the gastrointestinal tract) from the gut to the tumour sites. Once inside the tumours, these bacteria were found to “cross talk” with the suppressed NK cells, allowing them to improve their antitumour attack. The researchers found that Bifidobacteria increased in abundance in mice fed a high-salt diet.
When salt was combined with a low dose of one of the most effective cancer drugs, anti-PD1 immunotherapy, the two acted synergistically and dramatically regressed the tumour growth, the report says. The researchers conclude that “HSD causes increased immune activation, which leads to tumour killing through Bifidobacterium and NK cell cross talk”.
1. Rizvi, Z. A. et al. High-salt diet mediates interplay between NK cells and gut microbiota to induce potent tumor immunity. Science advances (2021) Doi:10.1126/sciadv.abg5016