Bowel cancer, also known as colorectal cancer, is one of the most common types of cancer worldwide.

According to Cancer Research UK, around 42,000 people in the UK are diagnosed with bowel cancer each year, with more than half of these cases occurring in people over the age of 70. While there are many risk factors associated with bowel cancer, recent research has suggested that diet and the health of the microbiome may play an important role in its development.

The Microbiome

The microbiome is a collection of microbes that live in the gut. These microbes include bacteria, viruses, fungi and other microorganisms.

The microbiome plays an important role in digestion, nutrient absorption, immune function and other bodily processes. The composition of the microbiome can be influenced by a range of factors including diet, antibiotics, stress, age and genetics.

Bowel Cancer and Diet

Diet has long been recognised as a risk factor for bowel cancer. One of the most consistent findings is that a diet high in red and processed meat is associated with an increased risk of bowel cancer.

A large study published in the British Journal of Cancer found that people who consumed the most red and processed meat had a 20-30% higher risk of bowel cancer compared to those who consumed the least.

In addition, a diet that is low in fruits, vegetables and whole grains has also been linked to an increased risk of bowel cancer.

A study published in the journal Gut found that people who consumed a Western-style diet that was high in meat, fat and refined grains had a 50% higher risk of bowel cancer compared to those who consumed a more plant-based diet.

Gut Microbiome and Bowel Cancer

Recent research has suggested that the health of the gut microbiome may also play an important role in the development of bowel cancer.

A study published in the International Journal of Cancer found that people who had high levels of a bacterium called Fusobacterium nucleatum in their gut microbiome were more likely to develop bowel cancer than those who did not.

Other studies have shown that the composition of the gut microbiome can influence the development of bowel cancer.

For example, a study published in the journal Nature Communications found that when mice were given antibiotics that disrupted their gut microbiome, they were more likely to develop bowel cancer.

How Diet Affects the Gut Microbiome

Diet is one of the most important factors that can influence the health of the gut microbiome.

Certain types of foods, such as fruits, vegetables, whole grains and legumes, contain complex carbohydrates that are not fully digested in the small intestine. These carbohydrates then pass through to the colon where they are fermented by bacteria in the gut microbiome.

The fermentation process produces short-chain fatty acids (SCFAs), which are an important energy source for the cells that line the colon.

SCFAs have also been shown to have anti-inflammatory and anti-cancer properties, and may help to protect against the development of bowel cancer.

In contrast, a diet that is high in fat, red and processed meat, and low in fruits, vegetables and whole grains, can alter the composition of the gut microbiome and reduce the production of SCFAs.

This can increase the risk of inflammation and promote the growth of harmful bacteria, which may contribute to the development of bowel cancer.

Conclusion

Bowel cancer is a complex disease that is influenced by a range of factors. While diet has long been recognised as a risk factor for bowel cancer, recent research has highlighted the important role of the gut microbiome in this disease.

A diet that is high in fruits, vegetables, whole grains and legumes can promote the growth of beneficial bacteria in the gut microbiome and reduce the risk of bowel cancer, while a diet that is high in fat and red and processed meat can disrupt the gut microbiome and increase the risk of this disease.

By making simple changes to our diet, we can help to support the health of our gut microbiome and reduce our risk of bowel cancer.