Initial gut microbiota composition is a determining factor in the promotion of colorectal cancer by oral iron supplementation: evidence from a murine modelOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
Researchers tested whether the starting gut microbiota shapes how oral iron supplementation affects colorectal cancer (CRC) risk. ApcMin/+ mice received fecal microbiota transplants (FMT) from healthy human donors, CRC patients, or mice, then an iron sufficient or iron excess diet.
How was it studied?
After FMT, mice were fed 50 ppm (sufficient) or 500 ppm (excess) iron diets for four weeks. Investigators tracked tumor count, size, grade, and Ki-67 proliferation, and profiled gut microbiota by 16S rRNA sequencing, then tested specific bacterial strains by oral gavage.
What did they find?
Iron excess increased colorectal tumor count, size, and in situ carcinoma incidence only in mice given CRC patient microbiota, not healthy donor or mouse microbiota. Faecalibaculum rodentium, Holdemanella biformis, Bifidobacterium pseudolongum, and Alistipes inops each protected CRC-microbiota mice against iron driven tumorigenesis, partly by raising fecal butyrate and lowering colonic IFN gamma.
Why it matters
The findings suggest a person's baseline gut microbiota, not iron alone, determines whether oral iron supplementation fuels colorectal tumor growth. Microbiota targeted interventions could help make iron therapy safer for anemic CRC patients.