Let's start with what we have known for a long time: fiber is our friend. In layman's terms, we would say: If a person has regular bowel movements, they don't need to go to the doctor. Fiber, found in fruits, vegetables, and whole grains, ensures that the stool moves regularly, prevents irritation of the intestines, promotes the growth of beneficial bacteria, and keeps the internal walls of the intestines healthy.

One of the important roles of fiber is also to nourish beneficial bacteria in our intestines. These bacteria produce beneficial substances from fiber, including short-chain fatty acids such as butyrate, which have strong anti-cancer effects. Butyrate reduces inflammation, helps cells regenerate, and inhibits harmful bacteria.

And now comes the crucial part: a study from the University of Toronto has shown that consuming a low-carbohydrate diet (thus also low in fiber) can inadvertently create a breeding ground for dangerous bacteria. One of them is a specific type of E. coli bacteria that produces a toxic substance called colibactin. This substance damages the DNA of cells in the colon, and as we know, DNA damage often leads to the development of cancer.

To make it clearer: colibactin is not something we can feel or detect. It works silently but very dangerously. It damages the inner cells of the intestine, especially when there is not enough protective mucus. This mucous layer acts as an invisible barrier between bacteria and the walls of the intestines. When we consume insufficient fiber, this layer becomes thinner, allowing bacteria to come closer and do more harm.

In the mentioned study, they used mice fed in three ways: with a normal diet, a Western diet (high in fat and sugar), and a diet very low in carbohydrates. Only those on the low-carb diet exposed to E. coli producing colibactin began to develop colon cancer.

What does this mean for you?

If you decide to eat fewer carbohydrates, you also reduce the intake of fruits, vegetables, and grains – basically, foods high in fiber. An average apple contains about 4 grams of fiber, a cup of cooked beans even 15 grams, and an adult should consume at least 25 to 30 grams per day. In reality, most people do not even consume 15 grams daily, which means we are already deficient without a diet.

Colon cancer is a serious issue. According to data from several oncology institutes, this cancer ranks among the top three most common cancers in both sexes. The number of new cases increases every year to the point where we can no longer ignore the problem.

How is this connected to bacteria?

Our intestines are home to trillions of microorganisms – forming a kind of internal ecosystem known as the gut microbiome. When this system is balanced, we are healthier, have a better immune system, better mood, and lower chances of developing diseases. However, if we disturb this system – as often happens with extreme diets – dangerous bacteria, like the harmful strain of E. coli that produces colibactin, take over. And thus, a chain reaction begins.

Scientists have also found that the risk significantly increases in people with genetic mutations in the DNA repair system. This means their bodies do not defend well against the damage caused by colibactin. One such condition is Lynch syndrome – a genetic defect that significantly increases the risk of colon cancer. About 15% of all cases of colon cancer involve these mutations.

Is there a solution?

Of course. One of the most natural and effective solutions is adding soluble fiber, such as inulin. Inulin is a type of fiber found, for example, in chicory, artichokes, and onions, and it has a special effect: it nourishes good bacteria, reduces inflammation, decreases the number of harmful bacteria, and reduces the chances of DNA damage.

Interestingly, research shows that adding just 10 grams of inulin daily can reduce inflammation in the intestines and improve the structure of the mucous layer. Moreover, in one study published in the journal Cell Host & Microbe, mice that consumed inulin developed half as many tumors in the colon as those who did not.

Special attention has also been drawn to the strain E. coli Nissle, found in some probiotic supplements. While it was long considered beneficial, researchers are now examining whether it is safe for people with faulty DNA repair genes, as this strain can also produce colibactin. Caution is advised here.

What does folk wisdom tell us?

If you listen to our grandmothers, they always said: Eat vegetables so your intestines don't get clogged. And they were right. When you consume fiber, you not only ensure regular bowel movements, but holistic intestinal health as well. In folk medicine, the intestine has always been linked to the overall health of the body – from skin to well-being. And modern science now confirms what the elders knew without microscopes.

Conclusion

A low-carb diet may indeed help with rapid weight loss, but it can lead to serious problems in the long run, especially if you do not pay attention to fiber intake. It's not just about digestion, it's about protection against one of the most dangerous cancers. Let's not forget that fiber acts as the cleansers of our bodies, which besides everything, also strengthens good bacteria, inhibits dangerous ones, and protects our insides.

So, do not fall for every trendy diet. Instead, reach for an apple every day, eat a handful of beans, a bowl of salad, or a slice of whole-grain bread. If possible, add garlic, onion, leek, artichokes, and chicory to your diet. All of these contain a lot of soluble fiber, which has been proven to reduce the risk of cancerous diseases.

Health always begins in the intestines, and the gut prefers natural, rich, diverse foods that smell like a garden and homemade kitchen. Treat it like your best friend so that it serves you well for many years to come.