In the UK, around 41,300 people are diagnosed with bowel cancer each year. The lifetime risk of developing bowel cancer is 5 – 6 % and around 60 % survive bowel cancer for 5 years or more. Some of the factors which increase the risk of developing bowel cancer include inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis.
In patients with bowel cancer and inflammatory bowel diseases, there is a change in gut flora, or gut microbiota. The microbiota is produced by fungi, bacteria and viruses, and the composition of the microbiota depends on diet and the bacteria present in the food we eat. Having a wide range of microorganisms in the gut is crucial when you want to maintain a strong immune system. Changes in the microbiota are associated with bowel cancer, and therefore, Emilie Viennois, Ph.D. at Georgia State University Institute for Biomedical Sciences, believes that there might be a connection between common additives, which change the gut microbiota, and the development of bowel cancer.
The number of annual cases of bowel cancer has risen dramatically since the middle of the twentieth century. According to Emilie Viennois, the change in microbiota makes is easier for tumours to develop. Severe changes in gut flora, caused by e.g. dietary changes, lifestyle or infections can change the balance between a person’s own microorganisms and microorganisms coming from the environment. This can lead to inflammatory bowel disease which in turn can lead to bowel tumours.
Together with her team of scientists, Emilie Viennois has examined the effect of certain dietary changes and the development of tumours in mice. Their study showed that low concentrations of two commonly used emulsifiers, carboxymethyl cellulose and polysorbate-80, caused inflammation and obesity in the mice. The study showed that eating emulsifiers drastically changed the microbiota compositions, and that the emulsifiers advance inflammation, thus creating a favourable environment for cancer to develop in.
This strengthens the assumption that microbiota plays an important role in the development of tumours. The results support the idea that a change in gut microbiota causes inflammation that promotes bowel cancer.
Scientists are now going to examine which microorganisms are responsible for this effect and also which specific mechanisms promote cancer.
