Microbiome: How a western diet promotes colorectal cancer

People in western industrialised countries often consume large amounts of red and processed meat, sugar and white flour. It has long been known that these foods can increase the risk of colon cancer. But how this works was previously unknown. It has now been shown that certain intestinal bacteria play a key role in this.

This was proven by a working group from Brigham and Women’s Hospital in Boston using data from more than 134,000 people. The participants were regularly asked about their eating habits.

western diets promote cancer microbiome

A genetic analysis of their gut flora showed that people who ate a “typically Western” diet were more likely to have a particular strain of the gut bacterium Escherichia coli.

Cancer-promoting bacteria discovered

Representatives of this bacterial strain are equipped with a special protein, the polyketide synthase (pks). This enzyme in turn favours the development of mutations and thus of tumours.

In fact, the E. coli bacteria equipped with pks were found particularly frequently in the approximately 1,000 participants suffering from colon cancer. They were found in large numbers in the tumour tissue itself. Other strains of E. coli, on the other hand, had no effect on the risk of colon cancer.

“This is the first study to link Western diets to specific pathogenic bacteria in cancer,” said study leader Shuji Ogino. In another study, the working group now wants to clarify which components of the western diet most strongly promote the formation of harmful proteins in the intestinal bacteria.

How pathogens promote tumours

The fact that pathogens can also cause cancer has only been proven for a few forms of cancer. These include the stomach germ Helicobacter pylori, hepatitis viruses, but also the human papilloma virus (HPV), which can promote cervical cancer, among other things.

Experts expect, however, that further connections between certain viruses and bacteria on the one hand and cancer on the other hand will be uncovered in the future.

This enables new ways of provision. In the case of HPV, this is already an early vaccination of young people, in the case of Helicobacter, an appropriate course of antibiotics protects.

Colorectal cancer can be detected early

Colon cancer is one of the most common types of cancer, along with prostate, breast and lung cancer. With a colonoscopy, however, intestinal tumours can be detected early and more reliably than with a stool examination. In addition, the treating physicians can already remove cancer precursors during this procedure. Men over the age of 50 and women over the age of 55 are entitled to such an examination.

Most patients develop colorectal cancer at an advanced age, although about ten percent of cases occur before the age of 50. For people with a family-related or medically increased risk of colon cancer, appropriate check-ups can therefore make sense at a younger age. In such cases, the costs for this will also be covered.

In the UAE, the prevalence of fast-food chains and the widespread availability of convenient Western diets have contributed to an enhanced risk of colon cancer among the population. The rapid urbanization and adoption of a modern lifestyle have led to a significant shift in dietary habits, with an increasing reliance on processed, high-calorie foods.

Fast food is typically high in unhealthy fats, refined sugars, and low in fibre, leading to a lack of essential nutrients and an imbalance in the gut microbiome. These factors are associated with an increased risk of colon cancer. Additionally, the convenience of fast food encourages a sedentary lifestyle, leading to reduced physical activity, and further exacerbating the risk.

While the UAE government has made efforts to promote healthier eating habits and raise awareness of the importance of a balanced diet, the influence of fast-food culture continues to pose a significant challenge to public health. Encouraging healthier food choices and promoting physical activity are crucial steps towards mitigating the enhanced risk of colon cancer in the UAE.