According to a new study, preventing colon cancer might be accomplished by adjusting your diet or taking a pill containing “good” bacteria. The findings were published online on December 6 in the Journal of the National Cancer Institute by researchers at New York University School of Medicine, New York, NY, New York University Cancer Institute, New York, NY , the National Cancer Institute, National Institutes of Health, Bethesda, MD, and New York Veterans Affairs Medical Center, New York, NY. The lead researcher was Jiyoung Ahn, PhD, MS, RD, an Assistant Professor of Population Health and Environmental Medicine at New York University School of Medicine. In Los Angeles County, as well as nationally, colorectal cancer is second only to lung cancer in the number of deaths it causes. Every year in the United States, approximately 142,000 people are diagnosed with colorectal cancer, and about 51,000 people die of the disease.
The investigators compared 47 patients with colorectal cancer to 94 control subjects They found that patients with colorectal cancer had more “bad” bacteria in their intestinal tract than individuals without cancer. They also had fewer “good” bacteria: probiotic bacteria. The study authors note that evidence has been accumulating that a connection exists between intestinal bacteria and colorectal cancer; however, they note that their study is the first to compare cancer patients with a control group and evaluate for conditions that might affect the outcome. The study revealed that among individuals with colorectal cancer, there were higher numbers of Fusobacteria and Porphyromonas bacteria than in patients who did not have the cancer. Fusobacteria and Porphyromonas are prevalent in both the mouth and intestinal tract; the bacteria are associated with inflammation of the digestive tract as well as periodontal disease.
In addition to the prevalence of “bad” bacteria, the investigators noted lower levels of Clostridia (“good” bacteria) in the intestinal tract of cancer patients. Clostridia is involved in the fermentation and digestion of fiber and carbohydrates. The bacterium also creates a chemical butyrate, which is believed to decrease inflammation and cancerous mutations in the colon. During the past decade, researchers have found a growing association between bacteria and gastrointestinal disorders. For example, it is now commonly accepted that most stomach ulcers are caused by infection of the bacteria Helicobacter pylori. Bacteria are also thought to be a causative factor for Crohn’s disease and even allergies.
A question that the study did not answer was: Does the imbalance of bad and good bacteria cause cancer, or does the cancer create an environment in which bad bacteria flourish? Dr. Ahn suspects that bacterial overgrowth triggers inflammation, which then leads to cancer, however, she cautions that prospective studies must be conducted to verify this hypothesis. If Dr. Ahn’s theory is correct, then it could lead to preventive measures for colon cancer (i.e., dietary adjustment, taking probiotics, and appropriate use of antibiotics). These methods could reduce the numbers of bad bacteria in the intestinal tract and allow beneficial bacteria to flourish.