Vitamin D Helps Support Cancer Immunity
A recent article titled, “Vitamin D regulates microbiome-dependent cancer immunity,” published April 25, 2024, in the journal Science, reported that vitamin D supports the growth of the intestinal bacterium Bacteroides fragilis in mice, which improved immunity to cancer.
Bacteroides fragilis is also part of the human microbiome. It has been observed that the composition of the gut microbiome in people with cancer who respond to immune checkpoint inhibitor immunotherapies differs from that of nonresponsive patients.
Less Tumor Growth in Mice
Among numerous findings revealed by the current research, mice that were bred to have greater vitamin D availability showed improved immune-dependent resistance to transplanted cancerous cells, which resulted in less tumor growth. These animals additionally showed greater responses to immunotherapies. Cohoused mice that were not genetically modified were also more resistant to tumors, which suggested involvement of microbiota.
Vitamin D Regulates Gut Microbiome
The research team discovered that vitamin D acts directly on intestinal epithelial cells to encourage the growth of the gut bacteria Bacteroides fragilis. “What we’ve shown here came as a surprise – vitamin D can regulate the gut microbiome to favor a type of bacteria which gives mice better immunity to cancer,” senior author Caetano Reis e Sousa of the Francis Crick Institute remarked.
“A key question we are currently trying to answer is how exactly vitamin D supports a ‘good’ microbiome,” added first author Evangelos Giampazolias, PhD. “If we can answer this, we might uncover new ways in which the microbiome influences the immune system, potentially offering exciting possibilities in preventing or treating cancer.”
Finding a New Connection
“Our findings indicate a previously unappreciated connection between vitamin D, microbial commensal communities, and immune responses to cancer,” Dr Giampazolias and colleagues concluded. “Collectively, they highlight vitamin D levels as a potential determinant of cancer immunity and immunotherapy success.”
