Colorectal cancer (CRC) is the third most common cancer found in men and women in the U.S., not counting skin cancers. The American Cancer Society estimates that this year in the U.S. there will be over 100,000 new cases of colon cancer, and over 40,000 new cases of rectal cancer. Over 50,000 people in the U.S. will die from CRC this year. The lifetime risk for developing CRC is about one in 20. Over 500,000 people worldwide die from CRC every year.
Eating a diet filled with red and processed meat, alcohol consumption and chronic inflammation of the gastrointestinal tract are significant risk factors for CRC. In a study recently published in the journal mBio, the online open-access journal of the American Society for Microbiology, researchers found a link between gut microbes and CRC. The researchers note that each of the risk factors for CRC are “closely associated with changes in composition and function of the complex community of microorganisms that inhabits our gastrointestinal tract.”Read more about junk food and colon cancer
There are trillions of bacteria that live in the gut and they are known collectively as the gut microbiome and individually as gut microbes. The researchers transferred gut microbes from mice with colon tumors to those without them and found they became prone to getting tumors. To transfer the gut microbes, the researchers collected feces and bedding from the mice with the induced tumors and gave them to the mice without tumors.
The mice given the microbes of those with tumors had more than twice as many colon tumors as mice given healthy microbes. Mice given antibiotics had much fewer tumors than mice given no antibiotics, and the tumors that were present in the mice given antibiotics were much smaller than those in the mice not given antibiotics. They also found that three weeks after the mice were given the microbes from those with tumors they had a gut microbiome that was very similar to the mice with tumors. “Our results suggest that interventions that target these changes in the microbiome may be an effective strategy for preventing the development of colorectal cancer,” the researchers concluded.
What will the discoveries mean for people suffering from CRC? Co-author of the study, Patrick Schloss from the University of Michigan said, “If you can better understand what functions in the microbial community are important for protecting against tumor formation or making it worse, we can hopefully translate those results to humans to understand why people do or do not get colorectal cancer, to help develop therapeutics or dietary manipulations to reduce people’s risk.”Read more about natural cancer fighters
A recent study linked gut microbes to obesity in mice. Researchers found that those who received gut microbes from obese humans gained more weight and accumulated more fat than mice given gut microbes from lean humans. Another recent study linked gut microbes to rheumatoid arthritis.
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