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The microbiota, an anti-cancer ally?

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Professor Eric Van Cutsem

Gastroenterologist and Digestive Oncologist, UZ Leuven

The microbiota, more commonly known as the “gut flora”, plays a vital role in our gut function and immune system. What influence does it have? How can we take care of it? Professor Eric Van Cutsem, gastroenterologist and digestive oncologist at UZ Leuven, explains.

The microbiota is the focus of a lot of research, especially in the response to cancer treatments, and it is undeniably a health ally. But what does this mean, exactly? “The microbiota is the system of micro-organisms (bacteria, viruses, fungi and parasites) found in an organ. We usually talk about intestinal microbiota, which is also called gut flora,” explains Professor Van Cutsem. “It varies greatly from person to person, but we assume there are 100 trillion bacteria in our body, most of which can be found in the intestine.”

An immune boost

“The microbiota is very useful. It helps us digest food and produce a series of chemicals that we cannot produce ourselves, but which are important for the gut function and our immune system,” he continues. “These chemicals are, among other things, vitamins, but they also have a whole range of functions that we do not yet know about. They are probably related to brain development (they probably play a role in our emotions and the way we think) and strengthen our defence mechanisms. Microbiota bacteria form a defence barrier against more invasive bacteria’, explains the Professor.

There is some evidence that the microbiota may influence the response to immunotherapy in some cancers.

A microbiota imbalance, a cause of disease

“There are several hypotheses linking the microbiota to certain diseases,” says Professor Van Cutsem. “This is particularly the case for Crohn’s disease, ulcerative colitis, obesity and type 2 diabetes. Many hypotheses also seem to demonstrate that it plays a role in certain mental illnesses and cancers, but there is no strong evidence for this. There are a lot of studies in progress.”

What causes a microbiota imbalance? “Improper use of antibiotics can contribute to this. I’m not saying that antibiotics should not be used for serious bacterial infections, but we should be careful not to overuse them.”

The virtuous circle of a healthy microbiota

Conversely, a healthy microbiota plays a beneficial role in the response to certain cancer treatments. “There is some evidence that the microbiota may influence the response to immunotherapy in some cancers. Studies are underway.”

To strengthen the microbiota, “a healthy lifestyle is important: get enough physical exercise and get enough sleep. But the most important factor is healthy food. Gut bacteria love fibre. They are found in vegetables, fruit, legumes and wholemeal bread. A diet rich in sugar and processed foods is certainly not conducive to a healthy microbiota and does not promote its virtuous role for the body.”

For a healthy microbiota, we should also consider probiotics. These friendly bacteria play an essential role in the proper functioning of the intestine, in maintaining an effective intestinal barrier, and in counteracting the adhesion of bacteriocins and pathogenic micro-organisms to the intestinal mucosa. Probiotics enrich the microbiota, restore gut homeostasis and improve gut function. The choice of probiotic is important: follow the advice of your doctor or pharmacist to find the one that is best suited to your needs and whose clinical studies have proven its efficacy.

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