Colorectal cancer is one of the most common cancers in industrialized countries. If genetic factors come into play, lifestyle habits, and in particular diet, can strongly influence the risk.
Why diet is essential in the face of colorectal cancer
For Julie Boët, dietician-nutritionist, the observation is clear: “Modern dietary habits, often rich in ultra-processed products, red meats and saturated fats, but low in fiber, can disrupt intestinal balance and create a breeding ground for chronic inflammation.”
Conversely, adopting a varied diet rich in protective nutrients helps support the intestinal microbiota, limit inflammation and preserve the digestive mucosa.
“A diet rich in fiber, antioxidants and protective fatty acids helps feed beneficial gut bacteria and produce anti-inflammatory compounds”underlines the specialist.
In this context, certain families of foods should be favored on a daily basis.
Whole grains: essential for nourishing the microbiota
For the dietitian, whole grains constitute an essential basis of a preventive diet.
“Unlike refined cereals, they preserve the entire grain, including the bran and the germ. They thus provide more fiber, B vitamins, minerals and antioxidant compounds.”
These fibers play a major physiological role. They are not digested in the small intestine but ferment in the colon under the action of the microbiota. “This fermentation produces short-chain fatty acids, including butyrate, an essential energy source for colon cells and a compound with anti-inflammatory properties.” These mechanisms also help regulate intestinal pH and limit the proliferation of harmful bacteria.
To take full advantage of their benefits, Julie Boët recommends favoring:
- Brown rice;
- Oats;
- Barley;
- Quinoa;
- Wholemeal breads and pastas.
“Pairing these cereals with vegetables or legumes increases the diversity of fibers consumed and further supports the richness of the microbiota.”
Fruits and vegetables: a protective pillar against inflammation
Fruits and vegetables also play a central role in prevention.
“They provide a wide variety of fiber, but also vitamins, minerals and bioactive compounds such as polyphenols and carotenoids”explains Julie Boët.
These substances have an important antioxidant role: They neutralize free radicals, unstable molecules that can damage cells and promote inflammatory processes.
Another often overlooked benefit: Fruits and vegetables contribute to hydration of the food bolus, facilitating intestinal transit and reducing the contact time between certain irritating substances and the wall of the colon.
To optimize their protective effects, the specialist advises:
- To vary the colors and the seasons;
- To consume both raw and cooked food;
- To favor gentle cooking (steamed, smothered, quickly fried in olive oil).
Dairy products: the protective role of calcium
Dairy products can also have their place in a preventive diet, provided they are well tolerated. “They are an important source of calcium, a mineral which seems to play a protective role in the intestine”specifies Julie Boët.
Calcium could in particular bind to certain bile acids and fatty acids present in the intestine and reduce their irritating potential for the colon mucosa.
Fermented products offer an additional benefit:
“Yogurts and some cheeses contain beneficial bacteria that support microbiota balance.”
She recommends prioritizing:
- Natural yogurts;
- Cottage cheese;
- Cheeses consumed in moderation.
Combined with fruits or whole grains, they can be snacks that promote digestive health.
Fish: protective omega-3s for the intestinal mucosa
Finally, fish — especially fatty — is of particular interest.
“Fish such as sardines, mackerel or salmon are rich in omega-3, lipids which play a recognized role in the modulation of inflammatory processes,” explains the dietician.
In the intestine, these fatty acids can help reduce certain inflammatory reactions of the mucosa and support a more favorable environment for the health of colon cells.
Fish also provides essential nutrients such as vitamin D, selenium and iodine.
Julie Boët therefore advises “to eat it several times a week, alternating between lean fish and fatty fish, and favoring simple cooking methods such as steaming, baking or foil-packing.
Foods to reduce to protect your colon
Certain products promote intestinal inflammation and may increase the risk of colorectal cancer, including:
- Red meats and processed meats;
- Ultra-processed products (industrial meals, packaged snacks);
- Very sweet cereals and flavored yogurts;
- Margarine;
- Sweet drinks;
- Alcohol.
However, these foods are taking up more and more space in the common diet.
Prevention tips to adopt on a daily basis
Diet is not enough: a holistic approach to lifestyle is essential.
Experts recommend:
- Do at least 30 minutes of physical activity per day (possible risk reduction of around 20%);
- Maintain a healthy weight (being overweight increases the risk by around 30%);
- Stop smoking (smokers have up to 50% more risk);
- Limit alcohol;
- Get screened from the age of 50 (as part of organized screening) or earlier, in case of doubt or history.
As Julie Boët summarizes: “Combining a protective diet, regular physical activity and a healthy lifestyle helps to preserve the integrity of the intestinal mucosa and reduce the factors favoring colorectal cancer.”