How gut bacteria beats colorectal cancer
Colorectal cancer is among the top 10 causes of cancer-related deaths in Kenya with an average of 1,500 new cases reported annually and more than 900 of them resulting in death.
Recent research indicates the role of gut bacteria in the pathogenesis (development) of colorectal cancer. Feeding on foods that have useful bacteria, such as fermented milk, supplements the gut bacteria in suppressing colorectal cancer in several ways.
The gut bacteria release chemicals that make colon and rectal epithelial junctions tight, preventing entry of pathogens that would otherwise cause inflammation of the organs. Inflammation of colon and rectum is key to the development of this cancer.
Secondly, gut bacteria compete for useful nutrients with pathogens and cancerous cells, depriving the tumour cells of the much-needed nutrients for growth. Thirdly, they release a number of metabolites, keeping the gut pH at optimal levels that do not support cancer growth and metastasis (spreading).
Feeding on fibre-rich foods promotes diversity and richness of gut bacteria and this had been associated with low incidence of colorectal cancers. However, indiscriminate use of antibiotics leads to killing of both useful and pathogenic bacteria and this could be a predisposing factor to cancer of the colon and rectum.
Further, the composition of gut bacteria is of species that are required to break fats into short-chain fats (SCFAs). When antibiotics kill the fat-breaking gut bacteria, chances of developing colorectal cancer increase, indicating that SCFAs play a role in prevention of colorectal cancer.
Gut bacteria also improves the ability of the immune system to produce immunoglobulin class A, IgA. This kind of antibody is needed to clear viruses and other pathogens from the gut, reducing chances of viral-induced colorectal cancer. Further, the bacteria enhance phagocytic capacity of gut macrophage cells, enhancing primary yet first line of defence system where colorectal cancer cells are phagocytosed and eliminated in a short time.
It is imperative that the general public is educated on observing proper nutrition as a key aspect of sustaining healthy gut bacteria. That will reduce their chances of developing colorectal cancer and other diseases.
Dr P. M. Mutua, immunologist, Makueni
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Kenya is going in the right direction in the war against cancer, one of the most dangerous diseases in the country.
This year is unique because 2018 Nobel Prize in Physiology or Medicine winners James P. Allison and Tasuku Honjo discoved cancer therapy by inhibition of negative immune regulation.
The government should support awareness campaigns while individuals ought to go for cancer screening for early diagnosis.
Benedict Ndeto, Kisumu