Diet Swap Alters Gut Bacteria, Signs of Colon Cancer Risk

What you eat can play a big role in preventing colorectal cancer, with research showing that fiber-filled foods lower risk; red and processed meats increase it. Now a study hones in on how diet can affect risk, showing that swapping a high-fiber healthy diet for a low-fiber western-style diet alters gut bacteria and signs of inflammation that may play a role in colon cancer.Choice between healthy apple and unhealthy hamburger

The study is published in Nature Communications and it adds to a growing body of research on how our bacteria – our microbiota – play a role in cancer risk.

For the study, researchers flipped the diets of 20 African Americans and 20 South Africans for two weeks. All the participants had colonoscopy exams before and after the diet swap.
The Americans were served African-style foods, almost quadrupling their fiber intake to an amount equal to over 3.5 cups of beans. At the same time, they cut their calories from fat in half. Africans went the opposite direction, dramatically cutting their fiber and upping their fat intake.

After two weeks on the African diet, the Americans had less markers of inflammation in the colon while those same markers increased among the Africans eating the less healthy diet. There were also opposing increases and decreases of the compound  butyrate, which forms from digesting fiber and is linked to lowering colon cancer risk. The American group was producing more butyrate; the Africans on the American diet less. Continue reading

Organization: Possible key to bacterial invasion for some colon cancers

A growing body of evidence indicates that the trillions of bacteria that live in the digestive tract – might play a role in altering cancer risk. Now, a study suggests that how those bacteria are organized and where they are located in the gut might influence the risk of certain colon cancers.

BacteriaThe study, published in The Proceedings of the National Academies of Science, focused on biofilms – communities of bacteria that help bacteria communicate with each other and grow more efficiently.

When bacteria organize into biofilms, they can breach the protective inner layer in the gut and invade the local tissue, promoting inflammation and possibly cancer.

We have an interesting relationship with the bacteria in our gut. Although many of the microbes provide beneficial services, bacteria – both “good” and “bad” – can cause us harm, so we keep them all at arm’s length, so to speak. Normal, healthy tissue in the colon is coated with a two-layered covering of mucus –a mesh-like outer layer and a gel-like inner layer. Whereas the outer layer creates a moist, cozy environment for bacteria, the inner layer is less hospitable: it provides the last line of defense against their invasion.

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Study: Fiber, Gut Bacteria and Colorectal Adenoma Risk


Evidence is strong that consuming high amounts of dietary fiber protects against colorectal cancer. Previous research has suggested that fiber may play a role in colon cancer prevention due to its interaction with trillions of bacteria in our gut.

Now, a study adds to that evidence by focusing on advanced colorectal adenoma, a non-cancerous tumor that has the potential to develop into cancer.

The study, published in The American Journal of Clinical Nutrition, suggests that a high-fiber diet promotes healthy gut bacteria and its byproducts.

Gut microbiota are the microorganisms that live in our digestive tracts – in our stomach, intestines, and colon. We have about 10 trillion human cells in our body, but we have way more – about 100 trillion – microorganisms residing in our gut. A growing body of research is showing that these microorganisms are important to our health – from training our immune system, to producing vitamins and fighting off harmful bacteria. Continue reading