Researchers from the Francis Crick Institute, the National Cancer Institute (NCI) of the U.S. National Institutes of Health (NIH), and Aalborg University in Denmark, have discovered that vitamin D promotes the growth of a specific type of gut bacteria in mice, leading to improved immunity against cancer. This finding, reported in Science, showed that mice fed a vitamin D-rich diet displayed enhanced immune resistance to experimentally transplanted cancers.Improved responses to immunotherapy were observed when gene editing was used to remove a protein that binds to vitamin D in the blood and keeps it away from tissues. Additionally, the study found that vitamin D acts on epithelial cells in the intestine, leading to an increase in the amount of a bacteria called Bacteroides fragilis. This microbe resulted in mice having better immunity to cancer, as transplanted tumors did not grow as much. However, the researchers are still unsure of the exact mechanism behind this. In order to test if the bacteria alone could provide better cancer immunity, mice on a normal diet were given Bacteroides fragilis.The ability to resist tumor growth was improved when mice were on a vitamin D-rich diet, but not when they were on a vitamin D-deficient diet. Earlier studies have suggested a connection between vitamin D deficiency and the risk of cancer in humans, but the evidence has not been conclusive. To investigate this further, the researchers analyzed data from 1.5 million people in Denmark, which showed a correlation between lower vitamin D levels and a higher cancer risk. Another analysis of a population of cancer patients also indicated that individuals with higher vitamin D levels were more likely to respond well to immune-based cancer treatments.While Bacteroides fragilis is present in the human microbiome, further research is required to determine if vitamin D can enhance immune resistance to cancer through similar means. Caetano Reis e Sousa, head of the Immunobiology Laboratory at the Crick, and senior author, stated, “What we’ve shown here came as a surprise — vitamin D can regulate the gut microbiome to favour a type of bacteria which gives mice better immunity to cancer. This could potentially be significant for cancer treatment in humans in the future, but we are not yet aware of how and why vitamin D has this effect.”Microbiome. Further research is necessary before we can definitively claim that addressing a vitamin D deficiency has advantages for cancer prevention or treatment.”
Evangelos Giampazolias, former postdoctoral researcher at the Crick, and now Group Leader of the Cancer Immunosurveillance Group at the Cancer Research UK Manchester Institute, stated: “Identifying the factors that differentiate a ‘good’ from a ‘bad’ microbiome is a significant challenge. We have discovered that vitamin D assists gut bacteria in promoting cancer immunity, enhancing the response to immunotherapy in mice.
“A crucial question we are presently attempting to address is how exactly vitamin D supports a ‘
The microbiome plays a significant role in the immune system, and understanding this relationship could lead to new ways to prevent or treat cancer. Romina Goldszmid, an investigator at NCI’s Center for Cancer Research, emphasized the importance of these findings in expanding our knowledge of how microbiota affects cancer immunity and the potential for dietary interventions to improve patient outcomes. However, more research is needed to fully grasp the mechanisms at play and how they can be used to develop personalized treatments.The study was financially supported by Cancer Research UK, the UK Medical Research Council, the Wellcome Trust, an ERC Advanced Investigator grant, a Wellcome Investigator Award, a prize from the Louis-Jeantet Foundation, the Intramural Research Program of the NCI, part of the National Institutes of Health, CCR-NCI, and the Danish National Research Foundation. Dr Nisharnthi Duggan, Research Information Manager at Cancer Research UK, stated that while it is known that vitamin D deficiency can lead to health issues, there is still insufficient evidence to connect vitamin D levels to the risk of cancer. This early-stage research in mice, along with an ana is promising.Analysis of population data from Denmark has discovered a potential connection between vitamin D and immune responses to cancer. However, further research is necessary to confirm this link. The study suggests that getting some sunlight can help the body produce vitamin D, but it is not necessary to sunbathe. Most people in the UK can obtain enough vitamin D by spending short periods of time in the summer sun, and it can also be acquired from the diet and supplements. It is known that staying safe in the sun can lower the risk of cancer, so it is important to seek shade, cover up, and apply sunscreen when the sun is strong.
