Bacteria linked to colon cancer
A peptide formed by a bacterial protease may stimulate cancer cell motility and invasion | By Sean Lawler
Gut bacteria have been implicated in colon cancer development , but their role in tumor invasion, which is modulated by environmental factors , has been unclear. In the November 17 EMBO Journal , Maria José Oliveira and colleagues at Gent University Hospital report that a metalloprotease from Listeria monocytogenes , in combination with a host protease, produces a peptide that stimulates motility and invasion of colon cancer cells ( EMBO J, 22:6161-6173, November 17, 2003).
The authors stress that these results do not directly implicate Listeria in cancer cell invasion, but state that their data "show that the combined action of diet, bacteria and host elements produce specific pro-invasive and motility-promoting ß-casein-derived peptides."
Commentary: (Dr. Kaczor)
The above article refers to gut bacteria and motility of cancer cells. The observation that a Listeria species of bacteria can affect colon cancer cell motility is an example of the importance that gut bacteria has in our health. We are just scratching the surface of understanding how our bodies interact with the environment that surrounds us. (It is important to remember that the GI tract is a tube that passes ingested materials through our bodies-it is essentially facing the outside environment much like our skin.)
The colon has over 500 species of bacteria, weighing between 6-8 pounds in total mass. The function of many of these organisms is unknown. We do know, however, that many of them produce vitamins (such as vitamin K) and protective substances (such as butyric acid). We also know that there are beneficial organisms and detrimental organisms. Many of these organisms are vying for the same food, and the growth of any of these organisms is based on winning the competition for food and space. (This is much like a garden with desired plants vying with the weeds for nutrients in the soil). While whole foods promote the growth of beneficial bacteria, processed foods promote the growth of detrimental bacteria. This may be a contributing factor in the high rate of cancer incidence in countries that eat refined foods.
What does this mean to the average American?
The ingestion of beneficial microorganisms is a glaring omission in the average American diet. Processed foods are devoid of organisms to prevent spoilage. Pasteurization kills all organisms-many of which are highly beneficial-in milk, juices and sauces. It is important for overall health to incorporate fermented foods in your diet, as well as eat organic, whole fruits and vegetables. Yogurt, Kifir, sauerkraut, miso and natto are a few of the fermented foods that have found their way back into food markets. Always look in the refrigerator section of the grocery store for fermented products, since they are alive and must be kept cold for viability! For anyone interested in further learning about fermented foods and their health benefits I highly recommend the book Nourishing Traditions by Sally Falon.