New research builds the case that a Western-style diet — rich in red and processed meat, sugar and refined grains/carbohydrates — is tied to higher risk of colorectal cancer through the intestinal microbiota. Investigators from Brigham and Women’s Hospital with collaborators looked at data from more than 134,000 participants from two U.S.-wide prospective cohort studies. The team analyzed dietary patterns as well as DNA from Escherichia coli strains found in more than 1,000 colorectal tumors. The team looked for bacterial strains carrying a distinct genetic island known as polyketide synthase (pks). Pks encodes an enzyme that has been shown to cause mutations in human cells. Overall, the team found that Western diet was associated with colorectal tumors containing high amounts of pks+ E. coli but not with tumors containing little to no amount of pks+ E. coli.
“These findings support our hypothesis that Western-style diets increase colorectal cancer risk through its effect on pks+ E. coli,” said corresponding author Shuji Ogino, MD, PhD, MS, of the Program in Molecular Pathological Epidemiology in the Department of Pathology at the Brigham. “This is the first study to link Western diet with specific pathogenic bacteria in cancer. Our next question is which component of western-style diet and lifestyle relates to colorectal cancer containing this bacterial species.”
Read more in Gastroenterology.
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Western-style Diet, pks Island-Carrying Escherichia coli, and Colorectal Cancer: Analyses from Two Large Prospective Cohort Studies
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A.T.C. previously served as a consultant for Bayer Healthcare and Pfizer Inc. J.A.M. has also served as an advisor/consultant to Ignyta, Array Pharmaceutical, and Cota Healthcare. C.S.F. is currently employed by Genentech, a subsidiary of Roche, and previously served as a consultant for Agios, Bain Capital, Bayer, Celgene, Dicerna, Five Prime Therapeutics, Gilead Sciences, Eli Lilly, Entrinsic Health, Genentech, KEW, Merck, Merrimack Pharmaceuticals, Pfizer Inc, Sanofi, Taiho, and Unum Therapeutics; C.S.F. also serves as a Director for CytomX Therapeutics and owns unexercised stock options for CytomX and Entrinsic Health. M.G. receives research funding from Bristol-Myers Squibb, Merck, Servier, and Janssen. This study was not funded by any of these commercial entities. No other conflicts of interest exist. The other authors declare that they have no conflicts of interest.