A study from Harvard Medical School found that a typical Western diet increases growth of specific bacteria in the gut called “polyketide synthase (pks+) E. Coli” that produce a chemical called colibactin, which causes DNA mutations that can turn normal colon cells into cancer cells (Gastroenterology, June 23, 2022). Other studies have found the same association (Cancer Sci, Jan 2022;113(1):277-286; Gastroenterology, 2017 Dec;153(6):1517-1530). Many studies have previously shown that the Western Diet causes inflammation, that is associated with increased risk for colon cancer (Gastroenterology, Jun 2017;152(8):1944-1953). A typical Western diet is high in pro-inflammatory foods such as red meat, processed meats, sugar-added foods, refined grains and fried foods; and low in anti-inflammatory foods such as vegetables, beans and unground whole grains.

The authors of the Harvard study used data from 134,775 adults participating in the Health Professionals Follow-up Study and the Nurses’ Health Study. They found the bacteria (polyketide synthase E. Coli) in 111 colon tumors, and the more components of the Western diet a person ate, the higher the levels of these bacteria in the cancer. The authors state: “Our findings provide evidence supporting the role of the gut microbiota in mediating the pathogenic link between diet and colorectal cancer.”

My Recommendations
The evidence gets stronger every day that several cancers, such as those of the breast, prostate or colon, are associated with an inflammatory lifestyle and diet that includes:
• sugar-added foods and refined carbohydrates (BMJ, February 14, 2018;360:k322)
• mammal meat and processed meats (Oncol Rev, Feb 10, 2015;9(1))
• fried foods (Prostate, Jun 2013;73(9):960–969)
Anti-inflmmatory Foods that help to protect you from cancer include fruits, vegetables, whole grains, beans, and nuts (BMJ, Mar 5, 2020;368:m511. PMC7190379).