A domestic research team has discovered for the first time in the world that a particular gut microbiome generated by consuming a lot of salty food makes brain tumors more malignant. This is expected to assist in developing dietary control strategies for brain tumor patients and gut microbiome-based treatments.
Professor Lee Heung-kyu's research team at the Korea Advanced Institute of Science and Technology (KAIST) noted on the 1st that they have identified for the first time the molecular principle that "salty food alters the gut microbiome ecosystem, and the specific metabolites produced by this worsen brain tumors." This research was published in the international biomedical journal Journal of Experimental Medicine on the 22nd of last month.
The research team divided mice with brain tumors into two groups and fed them salty and regular diets for four weeks, and then compared the results. As a result, it was found that the tumor size in the group of mice that consumed the salty diet increased and their survival rate decreased.
The same results were observed when gut microbiomes were eliminated with antibiotics or when the fecal microbiomes of mice fed a salty diet were transferred to those fed a regular diet. The research team explained that it is not merely salty food, but rather the changes in the gut microbiome that significantly affect the progression of brain tumors.
The gut of mice that ate a salty diet showed an increase in the harmful bacteria known as "Bacteroides vulgatus," and at the same time, the substance "propionate" became abnormally abundant. The research team viewed this specific gut microbiome as a key cause of worsening brain tumors. This substance activates hypoxia-inducible factors that cause cancer in brain tumor cells and induces the production of transforming growth factor beta (TGF-β) and collagen (COL1A1), which influence cancer growth and metastasis.
To verify whether this principle operates in human brain tumors, the research team analyzed genetic data from patients with glioblastoma. The results confirmed that the genes identified in the mouse experiments were also expressed in actual patients, and it was found that higher gene activity was associated with lower survival rates.
Professor Lee Heung-kyu said, "This research is the first case identifying at the molecular level how the intake of salty food affects the worsening of brain tumors," adding, "It could serve as an important clue for the future development of dietary control strategies or gut microbiome-based treatments for brain tumor patients."
References
Journal of Experimental Medicine (2025), DOI: https://doi.org/10.1084/jem.20241135