Carbohydrates-rich Diet Increases the Risk of Colon Cancer: The Role of the Gut Bacteria

Blog Health Carbohydrates-rich Diet Increases the Risk of Colon Cancer: The Role of the Gut Bacteria

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11.19.2019 0 comments By Viviana Anelli, Ph.D.

Carbohydrates account for about 50% of the daily intake for adults with a western-style diet, with starch and sucrose as the largest components.

Colon cancer is the second leading cause of cancer-related deaths in the United States and overall the lifetime risk of developing it is about 5%.

Although a relationship between a carbohydrate-rich diet and colon cancer is already known, the mechanism was not understood up until now.

In a recent article published on Cell (1) using a mouse model predisposed to develop colon cancer, scientists demonstrate that gut microbes stimulate cancer formation by providing metabolites that stimulate the excessive proliferation of the colon ephitelial cells (the cells that line the intestine). Uncontrolled cell proliferation is the initial step of cancer.

What is the mechanism? Gut bacteria use carbohydrates to produce a molecule called butyrate that initiates the process of excessive proliferation of the colon ephitelial cells. The major butyrate-producing bacteria belong to the family of Firmicutes and Fusobacterium nucleatum,and it is evident that a diet low in carbohydrates decreases the representative from these two classes of bacteria.

Is butyrate always associated with cancer? The answer is no, only in people carrying a mutation in a gene called MSH2 that predispose them to acquire colon cancer. As we don’t know if we carry the mutation in the gene MSH2 in our genome, it is important to prevent colon cancer by reducing carbohydrates in the diet as well as by having a balanced intestinal microbial community.

Colon cancer

The take-home message for your healthy life:

1- Decrease the amount of carbohydrates in the diet and always check the amount of sugar in the products you buy at the grocery store (as yogurt, cereal, almond milk). Choose unsweetened or a maximum of 2g sugar per serving portion.

2- Have a daily intake of probiotics. One excellent source of healthy and friendly bacteria and yeast is Kefir. Kefir helps strengthen the intestine and resist the growth of bad bacteria and pathogens.

Stay tuned: soon we will have a discussion on the healthy benefits of Kefir in our blog!


Belcheva A et al “Gut Microbial Metabolism Drives Transformation of Msh-Deficient Colon Ephithelial Cells”, Cell 158, 288-299, 2014.


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